Blame view
fs/eventpoll.c
66.1 KB
2874c5fd2 treewide: Replace... |
1 |
// SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4c Linux-2.6.12-rc2 |
2 |
/* |
5071f97ec epoll: fix epoll'... |
3 4 |
* fs/eventpoll.c (Efficient event retrieval implementation) * Copyright (C) 2001,...,2009 Davide Libenzi |
1da177e4c Linux-2.6.12-rc2 |
5 |
* |
1da177e4c Linux-2.6.12-rc2 |
6 |
* Davide Libenzi <davidel@xmailserver.org> |
1da177e4c Linux-2.6.12-rc2 |
7 |
*/ |
1da177e4c Linux-2.6.12-rc2 |
8 9 |
#include <linux/init.h> #include <linux/kernel.h> |
174cd4b1e sched/headers: Pr... |
10 |
#include <linux/sched/signal.h> |
1da177e4c Linux-2.6.12-rc2 |
11 12 13 14 15 16 17 |
#include <linux/fs.h> #include <linux/file.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/poll.h> |
1da177e4c Linux-2.6.12-rc2 |
18 19 20 21 22 |
#include <linux/string.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/spinlock.h> #include <linux/syscalls.h> |
1da177e4c Linux-2.6.12-rc2 |
23 24 25 26 27 |
#include <linux/rbtree.h> #include <linux/wait.h> #include <linux/eventpoll.h> #include <linux/mount.h> #include <linux/bitops.h> |
144efe3e3 [PATCH] sem2mutex... |
28 |
#include <linux/mutex.h> |
da66f7cb0 epoll: use anonym... |
29 |
#include <linux/anon_inodes.h> |
4d7e30d98 epoll: Add a flag... |
30 |
#include <linux/device.h> |
7c6ba364e ANDROID: fs: epol... |
31 |
#include <linux/freezer.h> |
7c0f6ba68 Replace <asm/uacc... |
32 |
#include <linux/uaccess.h> |
1da177e4c Linux-2.6.12-rc2 |
33 34 |
#include <asm/io.h> #include <asm/mman.h> |
60063497a atomic: use <linu... |
35 |
#include <linux/atomic.h> |
138d22b58 fs, epoll: add pr... |
36 37 |
#include <linux/proc_fs.h> #include <linux/seq_file.h> |
35280bd4a switch epoll_pwai... |
38 |
#include <linux/compat.h> |
ae10b2b4e epoll: optimize E... |
39 |
#include <linux/rculist.h> |
bf3b9f637 epoll: Add busy p... |
40 |
#include <net/busy_poll.h> |
1da177e4c Linux-2.6.12-rc2 |
41 |
|
1da177e4c Linux-2.6.12-rc2 |
42 43 44 45 |
/* * LOCKING: * There are three level of locking required by epoll : * |
144efe3e3 [PATCH] sem2mutex... |
46 |
* 1) epmutex (mutex) |
c7ea76302 epoll locks chang... |
47 |
* 2) ep->mtx (mutex) |
a218cc491 epoll: use rwlock... |
48 |
* 3) ep->lock (rwlock) |
1da177e4c Linux-2.6.12-rc2 |
49 50 |
* * The acquire order is the one listed above, from 1 to 3. |
a218cc491 epoll: use rwlock... |
51 |
* We need a rwlock (ep->lock) because we manipulate objects |
1da177e4c Linux-2.6.12-rc2 |
52 53 54 55 56 57 |
* from inside the poll callback, that might be triggered from * a wake_up() that in turn might be called from IRQ context. * So we can't sleep inside the poll callback and hence we need * a spinlock. During the event transfer loop (from kernel to * user space) we could end up sleeping due a copy_to_user(), so * we need a lock that will allow us to sleep. This lock is a |
d47de16c7 fix epoll single ... |
58 59 60 61 62 |
* mutex (ep->mtx). It is acquired during the event transfer loop, * during epoll_ctl(EPOLL_CTL_DEL) and during eventpoll_release_file(). * Then we also need a global mutex to serialize eventpoll_release_file() * and ep_free(). * This mutex is acquired by ep_free() during the epoll file |
1da177e4c Linux-2.6.12-rc2 |
63 64 |
* cleanup path and it is also acquired by eventpoll_release_file() * if a file has been pushed inside an epoll set and it is then |
bf6a41db7 fs/eventpoll.c: f... |
65 |
* close()d without a previous call to epoll_ctl(EPOLL_CTL_DEL). |
22bacca48 epoll: prevent cr... |
66 67 68 69 70 71 72 |
* It is also acquired when inserting an epoll fd onto another epoll * fd. We do this so that we walk the epoll tree and ensure that this * insertion does not create a cycle of epoll file descriptors, which * could lead to deadlock. We need a global mutex to prevent two * simultaneous inserts (A into B and B into A) from racing and * constructing a cycle without either insert observing that it is * going to. |
d8805e633 epoll: fix spurio... |
73 74 75 76 77 78 79 80 81 |
* It is necessary to acquire multiple "ep->mtx"es at once in the * case when one epoll fd is added to another. In this case, we * always acquire the locks in the order of nesting (i.e. after * epoll_ctl(e1, EPOLL_CTL_ADD, e2), e1->mtx will always be acquired * before e2->mtx). Since we disallow cycles of epoll file * descriptors, this ensures that the mutexes are well-ordered. In * order to communicate this nesting to lockdep, when walking a tree * of epoll file descriptors, we use the current recursion depth as * the lockdep subkey. |
d47de16c7 fix epoll single ... |
82 |
* It is possible to drop the "ep->mtx" and to use the global |
a218cc491 epoll: use rwlock... |
83 |
* mutex "epmutex" (together with "ep->lock") to have it working, |
d47de16c7 fix epoll single ... |
84 |
* but having "ep->mtx" will make the interface more scalable. |
144efe3e3 [PATCH] sem2mutex... |
85 |
* Events that require holding "epmutex" are very rare, while for |
d47de16c7 fix epoll single ... |
86 87 |
* normal operations the epoll private "ep->mtx" will guarantee * a better scalability. |
1da177e4c Linux-2.6.12-rc2 |
88 |
*/ |
1da177e4c Linux-2.6.12-rc2 |
89 |
/* Epoll private bits inside the event mask */ |
df0108c5d epoll: add EPOLLE... |
90 |
#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE) |
1da177e4c Linux-2.6.12-rc2 |
91 |
|
a9a08845e vfs: do bulk POLL... |
92 |
#define EPOLLINOUT_BITS (EPOLLIN | EPOLLOUT) |
b6a515c8a epoll: restrict E... |
93 |
|
a9a08845e vfs: do bulk POLL... |
94 |
#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | EPOLLERR | EPOLLHUP | \ |
b6a515c8a epoll: restrict E... |
95 |
EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE) |
5071f97ec epoll: fix epoll'... |
96 97 |
/* Maximum number of nesting allowed inside epoll sets */ #define EP_MAX_NESTS 4 |
1da177e4c Linux-2.6.12-rc2 |
98 |
|
b611967de [PATCH] epoll_pwa... |
99 |
#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event)) |
d47de16c7 fix epoll single ... |
100 |
#define EP_UNACTIVE_PTR ((void *) -1L) |
7ef9964e6 epoll: introduce ... |
101 |
#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry)) |
1da177e4c Linux-2.6.12-rc2 |
102 103 104 |
struct epoll_filefd { struct file *file; int fd; |
39732ca5a epoll: trim epite... |
105 |
} __packed; |
1da177e4c Linux-2.6.12-rc2 |
106 107 |
/* |
5071f97ec epoll: fix epoll'... |
108 109 |
* Structure used to track possible nested calls, for too deep recursions * and loop cycles. |
1da177e4c Linux-2.6.12-rc2 |
110 |
*/ |
5071f97ec epoll: fix epoll'... |
111 |
struct nested_call_node { |
1da177e4c Linux-2.6.12-rc2 |
112 |
struct list_head llink; |
5071f97ec epoll: fix epoll'... |
113 |
void *cookie; |
3fe4a975d epoll: fix nested... |
114 |
void *ctx; |
1da177e4c Linux-2.6.12-rc2 |
115 116 117 |
}; /* |
5071f97ec epoll: fix epoll'... |
118 119 |
* This structure is used as collector for nested calls, to check for * maximum recursion dept and loop cycles. |
1da177e4c Linux-2.6.12-rc2 |
120 |
*/ |
5071f97ec epoll: fix epoll'... |
121 122 |
struct nested_calls { struct list_head tasks_call_list; |
1da177e4c Linux-2.6.12-rc2 |
123 124 125 126 |
spinlock_t lock; }; /* |
d47de16c7 fix epoll single ... |
127 128 |
* Each file descriptor added to the eventpoll interface will * have an entry of this type linked to the "rbr" RB tree. |
39732ca5a epoll: trim epite... |
129 130 |
* Avoid increasing the size of this struct, there can be many thousands * of these on a server and we do not want this to take another cache line. |
d47de16c7 fix epoll single ... |
131 132 |
*/ struct epitem { |
ae10b2b4e epoll: optimize E... |
133 134 135 136 137 138 |
union { /* RB tree node links this structure to the eventpoll RB tree */ struct rb_node rbn; /* Used to free the struct epitem */ struct rcu_head rcu; }; |
d47de16c7 fix epoll single ... |
139 140 141 |
/* List header used to link this structure to the eventpoll ready list */ struct list_head rdllink; |
c7ea76302 epoll locks chang... |
142 143 144 145 146 |
/* * Works together "struct eventpoll"->ovflist in keeping the * single linked chain of items. */ struct epitem *next; |
d47de16c7 fix epoll single ... |
147 148 149 150 151 152 153 154 155 156 157 |
/* The file descriptor information this item refers to */ struct epoll_filefd ffd; /* Number of active wait queue attached to poll operations */ int nwait; /* List containing poll wait queues */ struct list_head pwqlist; /* The "container" of this item */ struct eventpoll *ep; |
d47de16c7 fix epoll single ... |
158 159 |
/* List header used to link this item to the "struct file" items list */ struct list_head fllink; |
4d7e30d98 epoll: Add a flag... |
160 |
/* wakeup_source used when EPOLLWAKEUP is set */ |
eea1d5859 epoll: use RCU to... |
161 |
struct wakeup_source __rcu *ws; |
4d7e30d98 epoll: Add a flag... |
162 |
|
c7ea76302 epoll locks chang... |
163 164 |
/* The structure that describe the interested events and the source fd */ struct epoll_event event; |
d47de16c7 fix epoll single ... |
165 166 167 |
}; /* |
1da177e4c Linux-2.6.12-rc2 |
168 |
* This structure is stored inside the "private_data" member of the file |
bf6a41db7 fs/eventpoll.c: f... |
169 |
* structure and represents the main data structure for the eventpoll |
1da177e4c Linux-2.6.12-rc2 |
170 171 172 |
* interface. */ struct eventpoll { |
1da177e4c Linux-2.6.12-rc2 |
173 |
/* |
d47de16c7 fix epoll single ... |
174 175 176 177 |
* This mutex is used to ensure that files are not removed * while epoll is using them. This is held during the event * collection loop, the file cleanup path, the epoll file exit * code and the ctl operations. |
1da177e4c Linux-2.6.12-rc2 |
178 |
*/ |
d47de16c7 fix epoll single ... |
179 |
struct mutex mtx; |
1da177e4c Linux-2.6.12-rc2 |
180 181 182 183 184 185 186 187 188 |
/* Wait queue used by sys_epoll_wait() */ wait_queue_head_t wq; /* Wait queue used by file->poll() */ wait_queue_head_t poll_wait; /* List of ready file descriptors */ struct list_head rdllist; |
a218cc491 epoll: use rwlock... |
189 190 |
/* Lock which protects rdllist and ovflist */ rwlock_t lock; |
67647d0fb epoll: fix some c... |
191 |
/* RB tree root used to store monitored fd structs */ |
b2ac2ea62 fs/epoll: use fas... |
192 |
struct rb_root_cached rbr; |
d47de16c7 fix epoll single ... |
193 194 195 |
/* * This is a single linked list that chains all the "struct epitem" that |
25985edce Fix common misspe... |
196 |
* happened while transferring ready events to userspace w/out |
a218cc491 epoll: use rwlock... |
197 |
* holding ->lock. |
d47de16c7 fix epoll single ... |
198 199 |
*/ struct epitem *ovflist; |
7ef9964e6 epoll: introduce ... |
200 |
|
4d7e30d98 epoll: Add a flag... |
201 202 |
/* wakeup_source used when ep_scan_ready_list is running */ struct wakeup_source *ws; |
7ef9964e6 epoll: introduce ... |
203 204 |
/* The user that created the eventpoll descriptor */ struct user_struct *user; |
28d82dc1c epoll: limit paths |
205 206 207 208 |
struct file *file; /* used to optimize loop detection check */ |
18306c404 epoll: replace ->... |
209 |
u64 gen; |
bf3b9f637 epoll: Add busy p... |
210 211 212 213 214 |
#ifdef CONFIG_NET_RX_BUSY_POLL /* used to track busy poll napi_id */ unsigned int napi_id; #endif |
efcdd350d fs/epoll: make ne... |
215 216 217 218 219 |
#ifdef CONFIG_DEBUG_LOCK_ALLOC /* tracks wakeup nests for lockdep validation */ u8 nests; #endif |
1da177e4c Linux-2.6.12-rc2 |
220 221 222 223 224 225 226 227 |
}; /* Wait structure used by the poll hooks */ struct eppoll_entry { /* List header used to link this structure to the "struct epitem" */ struct list_head llink; /* The "base" pointer is set to the container "struct epitem" */ |
4f0989dbf epoll: use real t... |
228 |
struct epitem *base; |
1da177e4c Linux-2.6.12-rc2 |
229 230 231 232 233 |
/* * Wait queue item that will be linked to the target file wait * queue head. */ |
ac6424b98 sched/wait: Renam... |
234 |
wait_queue_entry_t wait; |
1da177e4c Linux-2.6.12-rc2 |
235 236 237 238 |
/* The wait queue head that linked the "wait" wait queue item */ wait_queue_head_t *whead; }; |
1da177e4c Linux-2.6.12-rc2 |
239 240 241 242 243 |
/* Wrapper struct used by poll queueing */ struct ep_pqueue { poll_table pt; struct epitem *epi; }; |
5071f97ec epoll: fix epoll'... |
244 245 246 247 |
/* Used by the ep_send_events() function as callback private data */ struct ep_send_events_data { int maxevents; struct epoll_event __user *events; |
d7ebbe46f ep_send_events_pr... |
248 |
int res; |
5071f97ec epoll: fix epoll'... |
249 |
}; |
1da177e4c Linux-2.6.12-rc2 |
250 |
/* |
7ef9964e6 epoll: introduce ... |
251 252 |
* Configuration options available inside /proc/sys/fs/epoll/ */ |
7ef9964e6 epoll: introduce ... |
253 |
/* Maximum number of epoll watched descriptors, per user */ |
52bd19f76 epoll: convert ma... |
254 |
static long max_user_watches __read_mostly; |
7ef9964e6 epoll: introduce ... |
255 256 |
/* |
d47de16c7 fix epoll single ... |
257 |
* This mutex is used to serialize ep_free() and eventpoll_release_file(). |
1da177e4c Linux-2.6.12-rc2 |
258 |
*/ |
7ef9964e6 epoll: introduce ... |
259 |
static DEFINE_MUTEX(epmutex); |
1da177e4c Linux-2.6.12-rc2 |
260 |
|
18306c404 epoll: replace ->... |
261 |
static u64 loop_check_gen = 0; |
22bacca48 epoll: prevent cr... |
262 263 |
/* Used to check for epoll file descriptor inclusion loops */ static struct nested_calls poll_loop_ncalls; |
1da177e4c Linux-2.6.12-rc2 |
264 |
/* Slab cache used to allocate "struct epitem" */ |
e18b890bb [PATCH] slab: rem... |
265 |
static struct kmem_cache *epi_cache __read_mostly; |
1da177e4c Linux-2.6.12-rc2 |
266 267 |
/* Slab cache used to allocate "struct eppoll_entry" */ |
e18b890bb [PATCH] slab: rem... |
268 |
static struct kmem_cache *pwq_cache __read_mostly; |
1da177e4c Linux-2.6.12-rc2 |
269 |
|
28d82dc1c epoll: limit paths |
270 271 272 273 274 |
/* * List of files with newly added links, where we may need to limit the number * of emanating paths. Protected by the epmutex. */ static LIST_HEAD(tfile_check_list); |
7ef9964e6 epoll: introduce ... |
275 276 277 |
#ifdef CONFIG_SYSCTL #include <linux/sysctl.h> |
eec4844fa proc/sysctl: add ... |
278 |
static long long_zero; |
52bd19f76 epoll: convert ma... |
279 |
static long long_max = LONG_MAX; |
7ef9964e6 epoll: introduce ... |
280 |
|
1f7e0616c fs: convert use o... |
281 |
struct ctl_table epoll_table[] = { |
7ef9964e6 epoll: introduce ... |
282 |
{ |
7ef9964e6 epoll: introduce ... |
283 284 |
.procname = "max_user_watches", .data = &max_user_watches, |
52bd19f76 epoll: convert ma... |
285 |
.maxlen = sizeof(max_user_watches), |
7ef9964e6 epoll: introduce ... |
286 |
.mode = 0644, |
52bd19f76 epoll: convert ma... |
287 |
.proc_handler = proc_doulongvec_minmax, |
eec4844fa proc/sysctl: add ... |
288 |
.extra1 = &long_zero, |
52bd19f76 epoll: convert ma... |
289 |
.extra2 = &long_max, |
7ef9964e6 epoll: introduce ... |
290 |
}, |
ab09203e3 sysctl fs: Remove... |
291 |
{ } |
7ef9964e6 epoll: introduce ... |
292 293 |
}; #endif /* CONFIG_SYSCTL */ |
28d82dc1c epoll: limit paths |
294 295 296 297 298 299 |
static const struct file_operations eventpoll_fops; static inline int is_file_epoll(struct file *f) { return f->f_op == &eventpoll_fops; } |
b030a4dd6 [PATCH] Remove ev... |
300 |
|
67647d0fb epoll: fix some c... |
301 |
/* Setup the structure that is used as key for the RB tree */ |
b030a4dd6 [PATCH] Remove ev... |
302 303 304 305 306 307 |
static inline void ep_set_ffd(struct epoll_filefd *ffd, struct file *file, int fd) { ffd->file = file; ffd->fd = fd; } |
67647d0fb epoll: fix some c... |
308 |
/* Compare RB tree keys */ |
b030a4dd6 [PATCH] Remove ev... |
309 310 311 312 313 314 |
static inline int ep_cmp_ffd(struct epoll_filefd *p1, struct epoll_filefd *p2) { return (p1->file > p2->file ? +1: (p1->file < p2->file ? -1 : p1->fd - p2->fd)); } |
b030a4dd6 [PATCH] Remove ev... |
315 |
/* Tells us if the item is currently linked */ |
992991c03 fs/eventpoll.c: s... |
316 |
static inline int ep_is_linked(struct epitem *epi) |
b030a4dd6 [PATCH] Remove ev... |
317 |
{ |
992991c03 fs/eventpoll.c: s... |
318 |
return !list_empty(&epi->rdllink); |
b030a4dd6 [PATCH] Remove ev... |
319 |
} |
ac6424b98 sched/wait: Renam... |
320 |
static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_entry_t *p) |
971316f05 epoll: ep_unregis... |
321 322 323 |
{ return container_of(p, struct eppoll_entry, wait); } |
b030a4dd6 [PATCH] Remove ev... |
324 |
/* Get the "struct epitem" from a wait queue pointer */ |
ac6424b98 sched/wait: Renam... |
325 |
static inline struct epitem *ep_item_from_wait(wait_queue_entry_t *p) |
b030a4dd6 [PATCH] Remove ev... |
326 327 328 329 330 |
{ return container_of(p, struct eppoll_entry, wait)->base; } /* Get the "struct epitem" from an epoll queue wrapper */ |
cdac75e6f epoll: avoid kmem... |
331 |
static inline struct epitem *ep_item_from_epqueue(poll_table *p) |
b030a4dd6 [PATCH] Remove ev... |
332 333 334 |
{ return container_of(p, struct ep_pqueue, pt)->epi; } |
1da177e4c Linux-2.6.12-rc2 |
335 |
/* Initialize the poll safe wake up structure */ |
5071f97ec epoll: fix epoll'... |
336 |
static void ep_nested_calls_init(struct nested_calls *ncalls) |
1da177e4c Linux-2.6.12-rc2 |
337 |
{ |
5071f97ec epoll: fix epoll'... |
338 339 |
INIT_LIST_HEAD(&ncalls->tasks_call_list); spin_lock_init(&ncalls->lock); |
1da177e4c Linux-2.6.12-rc2 |
340 |
} |
5071f97ec epoll: fix epoll'... |
341 |
/** |
3fb0e584a epoll: move ready... |
342 343 344 345 346 347 348 349 350 |
* ep_events_available - Checks if ready events might be available. * * @ep: Pointer to the eventpoll context. * * Returns: Returns a value different than zero if ready events are available, * or zero otherwise. */ static inline int ep_events_available(struct eventpoll *ep) { |
c5a282e96 fs/epoll: reduce ... |
351 352 |
return !list_empty_careful(&ep->rdllist) || READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR; |
3fb0e584a epoll: move ready... |
353 |
} |
bf3b9f637 epoll: Add busy p... |
354 355 356 357 358 359 360 |
#ifdef CONFIG_NET_RX_BUSY_POLL static bool ep_busy_loop_end(void *p, unsigned long start_time) { struct eventpoll *ep = p; return ep_events_available(ep) || busy_loop_timeout(start_time); } |
bf3b9f637 epoll: Add busy p... |
361 362 363 364 365 366 367 368 369 |
/* * Busy poll if globally on and supporting sockets found && no events, * busy loop will return if need_resched or ep_events_available. * * we must do our busy polling with irqs enabled */ static void ep_busy_loop(struct eventpoll *ep, int nonblock) { |
bf3b9f637 epoll: Add busy p... |
370 371 372 373 |
unsigned int napi_id = READ_ONCE(ep->napi_id); if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep); |
bf3b9f637 epoll: Add busy p... |
374 375 376 377 |
} static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep) { |
bf3b9f637 epoll: Add busy p... |
378 379 |
if (ep->napi_id) ep->napi_id = 0; |
bf3b9f637 epoll: Add busy p... |
380 381 382 383 384 385 386 |
} /* * Set epoll busy poll NAPI ID from sk. */ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { |
bf3b9f637 epoll: Add busy p... |
387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 |
struct eventpoll *ep; unsigned int napi_id; struct socket *sock; struct sock *sk; int err; if (!net_busy_loop_on()) return; sock = sock_from_file(epi->ffd.file, &err); if (!sock) return; sk = sock->sk; if (!sk) return; napi_id = READ_ONCE(sk->sk_napi_id); ep = epi->ep; /* Non-NAPI IDs can be rejected * or * Nothing to do if we already have this ID */ if (napi_id < MIN_NAPI_ID || napi_id == ep->napi_id) return; /* record NAPI ID for use in next busy poll */ ep->napi_id = napi_id; |
bf3b9f637 epoll: Add busy p... |
416 |
} |
514056d50 fs/eventpoll.c: s... |
417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 |
#else static inline void ep_busy_loop(struct eventpoll *ep, int nonblock) { } static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep) { } static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { } #endif /* CONFIG_NET_RX_BUSY_POLL */ |
3fb0e584a epoll: move ready... |
432 |
/** |
5071f97ec epoll: fix epoll'... |
433 434 435 436 437 438 |
* ep_call_nested - Perform a bound (possibly) nested call, by checking * that the recursion limit is not exceeded, and that * the same nested call (by the meaning of same cookie) is * no re-entered. * * @ncalls: Pointer to the nested_calls structure to be used for this call. |
5071f97ec epoll: fix epoll'... |
439 440 441 |
* @nproc: Nested call core function pointer. * @priv: Opaque data to be passed to the @nproc callback. * @cookie: Cookie to be used to identify this nested call. |
3fe4a975d epoll: fix nested... |
442 |
* @ctx: This instance context. |
5071f97ec epoll: fix epoll'... |
443 444 445 |
* * Returns: Returns the code returned by the @nproc callback, or -1 if * the maximum recursion limit has been exceeded. |
1da177e4c Linux-2.6.12-rc2 |
446 |
*/ |
74bdc1298 fs/epoll: remove ... |
447 |
static int ep_call_nested(struct nested_calls *ncalls, |
5071f97ec epoll: fix epoll'... |
448 |
int (*nproc)(void *, void *, int), void *priv, |
3fe4a975d epoll: fix nested... |
449 |
void *cookie, void *ctx) |
1da177e4c Linux-2.6.12-rc2 |
450 |
{ |
5071f97ec epoll: fix epoll'... |
451 |
int error, call_nests = 0; |
1da177e4c Linux-2.6.12-rc2 |
452 |
unsigned long flags; |
5071f97ec epoll: fix epoll'... |
453 454 455 |
struct list_head *lsthead = &ncalls->tasks_call_list; struct nested_call_node *tncur; struct nested_call_node tnode; |
1da177e4c Linux-2.6.12-rc2 |
456 |
|
5071f97ec epoll: fix epoll'... |
457 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
458 |
|
5071f97ec epoll: fix epoll'... |
459 460 461 462 463 |
/* * Try to see if the current task is already inside this wakeup call. * We use a list here, since the population inside this set is always * very much limited. */ |
b70c39409 fs/eventpoll.c: u... |
464 |
list_for_each_entry(tncur, lsthead, llink) { |
3fe4a975d epoll: fix nested... |
465 |
if (tncur->ctx == ctx && |
74bdc1298 fs/epoll: remove ... |
466 |
(tncur->cookie == cookie || ++call_nests > EP_MAX_NESTS)) { |
1da177e4c Linux-2.6.12-rc2 |
467 468 469 470 |
/* * Ops ... loop detected or maximum nest level reached. * We abort this wake by breaking the cycle itself. */ |
abff55cee epoll: don't use ... |
471 472 |
error = -1; goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
473 474 |
} } |
5071f97ec epoll: fix epoll'... |
475 |
/* Add the current task and cookie to the list */ |
3fe4a975d epoll: fix nested... |
476 |
tnode.ctx = ctx; |
5071f97ec epoll: fix epoll'... |
477 |
tnode.cookie = cookie; |
1da177e4c Linux-2.6.12-rc2 |
478 |
list_add(&tnode.llink, lsthead); |
5071f97ec epoll: fix epoll'... |
479 |
spin_unlock_irqrestore(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
480 |
|
5071f97ec epoll: fix epoll'... |
481 482 |
/* Call the nested function */ error = (*nproc)(priv, cookie, call_nests); |
1da177e4c Linux-2.6.12-rc2 |
483 484 |
/* Remove the current task from the list */ |
5071f97ec epoll: fix epoll'... |
485 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
486 |
list_del(&tnode.llink); |
3fe4a975d epoll: fix nested... |
487 |
out_unlock: |
5071f97ec epoll: fix epoll'... |
488 489 490 491 |
spin_unlock_irqrestore(&ncalls->lock, flags); return error; } |
02edc6fc4 epoll: comment th... |
492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 |
/* * As described in commit 0ccf831cb lockdep: annotate epoll * the use of wait queues used by epoll is done in a very controlled * manner. Wake ups can nest inside each other, but are never done * with the same locking. For example: * * dfd = socket(...); * efd1 = epoll_create(); * efd2 = epoll_create(); * epoll_ctl(efd1, EPOLL_CTL_ADD, dfd, ...); * epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...); * * When a packet arrives to the device underneath "dfd", the net code will * issue a wake_up() on its poll wake list. Epoll (efd1) has installed a * callback wakeup entry on that queue, and the wake_up() performed by the * "dfd" net code will end up in ep_poll_callback(). At this point epoll * (efd1) notices that it may have some event ready, so it needs to wake up * the waiters on its poll wait list (efd2). So it calls ep_poll_safewake() * that ends up in another wake_up(), after having checked about the * recursion constraints. That are, no more than EP_MAX_POLLWAKE_NESTS, to * avoid stack blasting. * * When CONFIG_DEBUG_LOCK_ALLOC is enabled, make sure lockdep can handle * this special case of epoll. */ |
2dfa4eeab epoll keyed wakeu... |
517 |
#ifdef CONFIG_DEBUG_LOCK_ALLOC |
57a173bdf epoll: avoid call... |
518 |
|
efcdd350d fs/epoll: make ne... |
519 |
static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) |
5071f97ec epoll: fix epoll'... |
520 |
{ |
efcdd350d fs/epoll: make ne... |
521 |
struct eventpoll *ep_src; |
f6520c520 epoll: simplify e... |
522 |
unsigned long flags; |
efcdd350d fs/epoll: make ne... |
523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 |
u8 nests = 0; /* * To set the subclass or nesting level for spin_lock_irqsave_nested() * it might be natural to create a per-cpu nest count. However, since * we can recurse on ep->poll_wait.lock, and a non-raw spinlock can * schedule() in the -rt kernel, the per-cpu variable are no longer * protected. Thus, we are introducing a per eventpoll nest field. * If we are not being call from ep_poll_callback(), epi is NULL and * we are at the first level of nesting, 0. Otherwise, we are being * called from ep_poll_callback() and if a previous wakeup source is * not an epoll file itself, we are at depth 1 since the wakeup source * is depth 0. If the wakeup source is a previous epoll file in the * wakeup chain then we use its nests value and record ours as * nests + 1. The previous epoll file nests value is stable since its * already holding its own poll_wait.lock. */ if (epi) { if ((is_file_epoll(epi->ffd.file))) { ep_src = epi->ffd.file->private_data; nests = ep_src->nests; } else { nests = 1; } } spin_lock_irqsave_nested(&ep->poll_wait.lock, flags, nests); ep->nests = nests + 1; wake_up_locked_poll(&ep->poll_wait, EPOLLIN); ep->nests = 0; spin_unlock_irqrestore(&ep->poll_wait.lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
553 |
} |
57a173bdf epoll: avoid call... |
554 |
#else |
efcdd350d fs/epoll: make ne... |
555 |
static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) |
57a173bdf epoll: avoid call... |
556 |
{ |
efcdd350d fs/epoll: make ne... |
557 |
wake_up_poll(&ep->poll_wait, EPOLLIN); |
57a173bdf epoll: avoid call... |
558 559 560 |
} #endif |
971316f05 epoll: ep_unregis... |
561 562 563 564 565 |
static void ep_remove_wait_queue(struct eppoll_entry *pwq) { wait_queue_head_t *whead; rcu_read_lock(); |
138e4ad67 epoll: fix race b... |
566 567 568 569 570 571 572 |
/* * If it is cleared by POLLFREE, it should be rcu-safe. * If we read NULL we need a barrier paired with * smp_store_release() in ep_poll_callback(), otherwise * we rely on whead->lock. */ whead = smp_load_acquire(&pwq->whead); |
971316f05 epoll: ep_unregis... |
573 574 575 576 |
if (whead) remove_wait_queue(whead, &pwq->wait); rcu_read_unlock(); } |
1da177e4c Linux-2.6.12-rc2 |
577 |
/* |
d1bc90dd5 epoll: remove unn... |
578 579 580 |
* This function unregisters poll callbacks from the associated file * descriptor. Must be called with "mtx" held (or "epmutex" if called from * ep_free). |
1da177e4c Linux-2.6.12-rc2 |
581 |
*/ |
7699acd13 epoll cleanups: e... |
582 |
static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) |
1da177e4c Linux-2.6.12-rc2 |
583 |
{ |
7699acd13 epoll cleanups: e... |
584 585 |
struct list_head *lsthead = &epi->pwqlist; struct eppoll_entry *pwq; |
1da177e4c Linux-2.6.12-rc2 |
586 |
|
d1bc90dd5 epoll: remove unn... |
587 588 |
while (!list_empty(lsthead)) { pwq = list_first_entry(lsthead, struct eppoll_entry, llink); |
1da177e4c Linux-2.6.12-rc2 |
589 |
|
d1bc90dd5 epoll: remove unn... |
590 |
list_del(&pwq->llink); |
971316f05 epoll: ep_unregis... |
591 |
ep_remove_wait_queue(pwq); |
d1bc90dd5 epoll: remove unn... |
592 |
kmem_cache_free(pwq_cache, pwq); |
1da177e4c Linux-2.6.12-rc2 |
593 |
} |
1da177e4c Linux-2.6.12-rc2 |
594 |
} |
eea1d5859 epoll: use RCU to... |
595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 |
/* call only when ep->mtx is held */ static inline struct wakeup_source *ep_wakeup_source(struct epitem *epi) { return rcu_dereference_check(epi->ws, lockdep_is_held(&epi->ep->mtx)); } /* call only when ep->mtx is held */ static inline void ep_pm_stay_awake(struct epitem *epi) { struct wakeup_source *ws = ep_wakeup_source(epi); if (ws) __pm_stay_awake(ws); } static inline bool ep_has_wakeup_source(struct epitem *epi) { return rcu_access_pointer(epi->ws) ? true : false; } /* call when ep->mtx cannot be held (ep_poll_callback) */ static inline void ep_pm_stay_awake_rcu(struct epitem *epi) { struct wakeup_source *ws; rcu_read_lock(); ws = rcu_dereference(epi->ws); if (ws) __pm_stay_awake(ws); rcu_read_unlock(); } |
5071f97ec epoll: fix epoll'... |
626 627 628 629 630 631 632 633 |
/** * ep_scan_ready_list - Scans the ready list in a way that makes possible for * the scan code, to call f_op->poll(). Also allows for * O(NumReady) performance. * * @ep: Pointer to the epoll private data structure. * @sproc: Pointer to the scan callback. * @priv: Private opaque data passed to the @sproc callback. |
d8805e633 epoll: fix spurio... |
634 |
* @depth: The current depth of recursive f_op->poll calls. |
67347fe4e epoll: do not tak... |
635 |
* @ep_locked: caller already holds ep->mtx |
5071f97ec epoll: fix epoll'... |
636 637 638 |
* * Returns: The same integer error code returned by the @sproc callback. */ |
d85e2aa2e annotate ep_scan_... |
639 640 |
static __poll_t ep_scan_ready_list(struct eventpoll *ep, __poll_t (*sproc)(struct eventpoll *, |
5071f97ec epoll: fix epoll'... |
641 |
struct list_head *, void *), |
67347fe4e epoll: do not tak... |
642 |
void *priv, int depth, bool ep_locked) |
5071f97ec epoll: fix epoll'... |
643 |
{ |
d85e2aa2e annotate ep_scan_... |
644 |
__poll_t res; |
5071f97ec epoll: fix epoll'... |
645 |
struct epitem *epi, *nepi; |
296e236e9 epoll: fix epoll'... |
646 |
LIST_HEAD(txlist); |
5071f97ec epoll: fix epoll'... |
647 |
|
92e641784 s/epoll: robustif... |
648 |
lockdep_assert_irqs_enabled(); |
5071f97ec epoll: fix epoll'... |
649 650 |
/* * We need to lock this because we could be hit by |
e057e15ff epoll: clean up e... |
651 |
* eventpoll_release_file() and epoll_ctl(). |
5071f97ec epoll: fix epoll'... |
652 |
*/ |
67347fe4e epoll: do not tak... |
653 654 655 |
if (!ep_locked) mutex_lock_nested(&ep->mtx, depth); |
5071f97ec epoll: fix epoll'... |
656 657 658 659 660 661 662 663 664 |
/* * Steal the ready list, and re-init the original one to the * empty list. Also, set ep->ovflist to NULL so that events * happening while looping w/out locks, are not lost. We cannot * have the poll callback to queue directly on ep->rdllist, * because we want the "sproc" callback to be able to do it * in a lockless way. */ |
a218cc491 epoll: use rwlock... |
665 |
write_lock_irq(&ep->lock); |
296e236e9 epoll: fix epoll'... |
666 |
list_splice_init(&ep->rdllist, &txlist); |
c5a282e96 fs/epoll: reduce ... |
667 |
WRITE_ONCE(ep->ovflist, NULL); |
a218cc491 epoll: use rwlock... |
668 |
write_unlock_irq(&ep->lock); |
5071f97ec epoll: fix epoll'... |
669 670 671 672 |
/* * Now call the callback function. */ |
d85e2aa2e annotate ep_scan_... |
673 |
res = (*sproc)(ep, &txlist, priv); |
5071f97ec epoll: fix epoll'... |
674 |
|
a218cc491 epoll: use rwlock... |
675 |
write_lock_irq(&ep->lock); |
5071f97ec epoll: fix epoll'... |
676 677 678 679 680 |
/* * During the time we spent inside the "sproc" callback, some * other events might have been queued by the poll callback. * We re-insert them inside the main ready-list here. */ |
c5a282e96 fs/epoll: reduce ... |
681 |
for (nepi = READ_ONCE(ep->ovflist); (epi = nepi) != NULL; |
5071f97ec epoll: fix epoll'... |
682 683 684 685 686 687 688 |
nepi = epi->next, epi->next = EP_UNACTIVE_PTR) { /* * We need to check if the item is already in the list. * During the "sproc" callback execution time, items are * queued into ->ovflist but the "txlist" might already * contain them, and the list_splice() below takes care of them. */ |
992991c03 fs/eventpoll.c: s... |
689 |
if (!ep_is_linked(epi)) { |
c141175d0 epoll: make sure ... |
690 691 692 693 694 |
/* * ->ovflist is LIFO, so we have to reverse it in order * to keep in FIFO. */ list_add(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
695 |
ep_pm_stay_awake(epi); |
4d7e30d98 epoll: Add a flag... |
696 |
} |
5071f97ec epoll: fix epoll'... |
697 698 699 700 701 702 |
} /* * We need to set back ep->ovflist to EP_UNACTIVE_PTR, so that after * releasing the lock, events will be queued in the normal way inside * ep->rdllist. */ |
c5a282e96 fs/epoll: reduce ... |
703 |
WRITE_ONCE(ep->ovflist, EP_UNACTIVE_PTR); |
5071f97ec epoll: fix epoll'... |
704 705 706 707 708 |
/* * Quickly re-inject items left on "txlist". */ list_splice(&txlist, &ep->rdllist); |
4d7e30d98 epoll: Add a flag... |
709 |
__pm_relax(ep->ws); |
a218cc491 epoll: use rwlock... |
710 |
write_unlock_irq(&ep->lock); |
5071f97ec epoll: fix epoll'... |
711 |
|
67347fe4e epoll: do not tak... |
712 713 |
if (!ep_locked) mutex_unlock(&ep->mtx); |
5071f97ec epoll: fix epoll'... |
714 |
|
d85e2aa2e annotate ep_scan_... |
715 |
return res; |
5071f97ec epoll: fix epoll'... |
716 |
} |
ae10b2b4e epoll: optimize E... |
717 718 719 720 721 |
static void epi_rcu_free(struct rcu_head *head) { struct epitem *epi = container_of(head, struct epitem, rcu); kmem_cache_free(epi_cache, epi); } |
1da177e4c Linux-2.6.12-rc2 |
722 |
/* |
7699acd13 epoll cleanups: e... |
723 |
* Removes a "struct epitem" from the eventpoll RB tree and deallocates |
c7ea76302 epoll locks chang... |
724 |
* all the associated resources. Must be called with "mtx" held. |
7699acd13 epoll cleanups: e... |
725 726 727 |
*/ static int ep_remove(struct eventpoll *ep, struct epitem *epi) { |
7699acd13 epoll cleanups: e... |
728 |
struct file *file = epi->ffd.file; |
1da177e4c Linux-2.6.12-rc2 |
729 |
|
92e641784 s/epoll: robustif... |
730 |
lockdep_assert_irqs_enabled(); |
1da177e4c Linux-2.6.12-rc2 |
731 |
/* |
ee8ef0a4b epoll: use the wa... |
732 |
* Removes poll wait queue hooks. |
1da177e4c Linux-2.6.12-rc2 |
733 |
*/ |
7699acd13 epoll cleanups: e... |
734 |
ep_unregister_pollwait(ep, epi); |
1da177e4c Linux-2.6.12-rc2 |
735 |
|
7699acd13 epoll cleanups: e... |
736 |
/* Remove the current item from the list of epoll hooks */ |
684999149 Rename struct fil... |
737 |
spin_lock(&file->f_lock); |
ae10b2b4e epoll: optimize E... |
738 |
list_del_rcu(&epi->fllink); |
684999149 Rename struct fil... |
739 |
spin_unlock(&file->f_lock); |
1da177e4c Linux-2.6.12-rc2 |
740 |
|
b2ac2ea62 fs/epoll: use fas... |
741 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
1da177e4c Linux-2.6.12-rc2 |
742 |
|
a218cc491 epoll: use rwlock... |
743 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
744 |
if (ep_is_linked(epi)) |
c7ea76302 epoll locks chang... |
745 |
list_del_init(&epi->rdllink); |
a218cc491 epoll: use rwlock... |
746 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
747 |
|
eea1d5859 epoll: use RCU to... |
748 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
ae10b2b4e epoll: optimize E... |
749 750 751 752 753 754 755 756 |
/* * At this point it is safe to free the eventpoll item. Use the union * field epi->rcu, since we are trying to minimize the size of * 'struct epitem'. The 'rbn' field is no longer in use. Protected by * ep->mtx. The rcu read side, reverse_path_check_proc(), does not make * use of the rbn field. */ call_rcu(&epi->rcu, epi_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
757 |
|
52bd19f76 epoll: convert ma... |
758 |
atomic_long_dec(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
759 |
|
c7ea76302 epoll locks chang... |
760 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
761 |
} |
7699acd13 epoll cleanups: e... |
762 |
static void ep_free(struct eventpoll *ep) |
1da177e4c Linux-2.6.12-rc2 |
763 |
{ |
7699acd13 epoll cleanups: e... |
764 765 |
struct rb_node *rbp; struct epitem *epi; |
1da177e4c Linux-2.6.12-rc2 |
766 |
|
7699acd13 epoll cleanups: e... |
767 768 |
/* We need to release all tasks waiting for these file */ if (waitqueue_active(&ep->poll_wait)) |
efcdd350d fs/epoll: make ne... |
769 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
770 |
|
7699acd13 epoll cleanups: e... |
771 772 773 |
/* * We need to lock this because we could be hit by * eventpoll_release_file() while we're freeing the "struct eventpoll". |
d47de16c7 fix epoll single ... |
774 |
* We do not need to hold "ep->mtx" here because the epoll file |
7699acd13 epoll cleanups: e... |
775 776 |
* is on the way to be removed and no one has references to it * anymore. The only hit might come from eventpoll_release_file() but |
25985edce Fix common misspe... |
777 |
* holding "epmutex" is sufficient here. |
7699acd13 epoll cleanups: e... |
778 779 |
*/ mutex_lock(&epmutex); |
1da177e4c Linux-2.6.12-rc2 |
780 781 |
/* |
7699acd13 epoll cleanups: e... |
782 |
* Walks through the whole tree by unregistering poll callbacks. |
1da177e4c Linux-2.6.12-rc2 |
783 |
*/ |
b2ac2ea62 fs/epoll: use fas... |
784 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
7699acd13 epoll cleanups: e... |
785 786 787 |
epi = rb_entry(rbp, struct epitem, rbn); ep_unregister_pollwait(ep, epi); |
91cf5ab60 epoll: add a resc... |
788 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
789 |
} |
1da177e4c Linux-2.6.12-rc2 |
790 791 |
/* |
7699acd13 epoll cleanups: e... |
792 793 |
* Walks through the whole tree by freeing each "struct epitem". At this * point we are sure no poll callbacks will be lingering around, and also by |
d47de16c7 fix epoll single ... |
794 |
* holding "epmutex" we can be sure that no file cleanup code will hit |
a218cc491 epoll: use rwlock... |
795 |
* us during this operation. So we can avoid the lock on "ep->lock". |
ddf676c38 epoll: lock ep->m... |
796 797 |
* We do not need to lock ep->mtx, either, we only do it to prevent * a lockdep warning. |
1da177e4c Linux-2.6.12-rc2 |
798 |
*/ |
ddf676c38 epoll: lock ep->m... |
799 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
800 |
while ((rbp = rb_first_cached(&ep->rbr)) != NULL) { |
7699acd13 epoll cleanups: e... |
801 802 |
epi = rb_entry(rbp, struct epitem, rbn); ep_remove(ep, epi); |
91cf5ab60 epoll: add a resc... |
803 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
804 |
} |
ddf676c38 epoll: lock ep->m... |
805 |
mutex_unlock(&ep->mtx); |
1da177e4c Linux-2.6.12-rc2 |
806 |
|
7699acd13 epoll cleanups: e... |
807 |
mutex_unlock(&epmutex); |
d47de16c7 fix epoll single ... |
808 |
mutex_destroy(&ep->mtx); |
7ef9964e6 epoll: introduce ... |
809 |
free_uid(ep->user); |
4d7e30d98 epoll: Add a flag... |
810 |
wakeup_source_unregister(ep->ws); |
f0ee9aabb epoll: move kfree... |
811 |
kfree(ep); |
7699acd13 epoll cleanups: e... |
812 |
} |
1da177e4c Linux-2.6.12-rc2 |
813 |
|
7699acd13 epoll cleanups: e... |
814 815 816 |
static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep = file->private_data; |
1da177e4c Linux-2.6.12-rc2 |
817 |
|
f0ee9aabb epoll: move kfree... |
818 |
if (ep) |
7699acd13 epoll cleanups: e... |
819 |
ep_free(ep); |
7699acd13 epoll cleanups: e... |
820 |
|
7699acd13 epoll cleanups: e... |
821 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
822 |
} |
d85e2aa2e annotate ep_scan_... |
823 |
static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head, |
37b5e5212 epoll: remove ep_... |
824 825 826 827 828 829 830 831 832 |
void *priv); static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, poll_table *pt); /* * Differs from ep_eventpoll_poll() in that internal callers already have * the ep->mtx so we need to start from depth=1, such that mutex_lock_nested() * is correctly annotated. */ |
d85e2aa2e annotate ep_scan_... |
833 |
static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt, |
bec1a502d eventpoll: consti... |
834 |
int depth) |
450d89ec0 epoll: cleanup: h... |
835 |
{ |
37b5e5212 epoll: remove ep_... |
836 837 |
struct eventpoll *ep; bool locked; |
450d89ec0 epoll: cleanup: h... |
838 |
pt->_key = epi->event.events; |
37b5e5212 epoll: remove ep_... |
839 |
if (!is_file_epoll(epi->ffd.file)) |
9965ed174 fs: add new vfs_p... |
840 |
return vfs_poll(epi->ffd.file, pt) & epi->event.events; |
450d89ec0 epoll: cleanup: h... |
841 |
|
37b5e5212 epoll: remove ep_... |
842 843 844 |
ep = epi->ffd.file->private_data; poll_wait(epi->ffd.file, &ep->poll_wait, pt); locked = pt && (pt->_qproc == ep_ptable_queue_proc); |
450d89ec0 epoll: cleanup: h... |
845 |
|
37b5e5212 epoll: remove ep_... |
846 847 848 |
return ep_scan_ready_list(epi->ffd.file->private_data, ep_read_events_proc, &depth, depth, locked) & epi->event.events; |
450d89ec0 epoll: cleanup: h... |
849 |
} |
d85e2aa2e annotate ep_scan_... |
850 |
static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head, |
296e236e9 epoll: fix epoll'... |
851 |
void *priv) |
5071f97ec epoll: fix epoll'... |
852 853 |
{ struct epitem *epi, *tmp; |
626cf2366 poll: add poll_re... |
854 |
poll_table pt; |
37b5e5212 epoll: remove ep_... |
855 |
int depth = *(int *)priv; |
5071f97ec epoll: fix epoll'... |
856 |
|
626cf2366 poll: add poll_re... |
857 |
init_poll_funcptr(&pt, NULL); |
37b5e5212 epoll: remove ep_... |
858 |
depth++; |
450d89ec0 epoll: cleanup: h... |
859 |
|
5071f97ec epoll: fix epoll'... |
860 |
list_for_each_entry_safe(epi, tmp, head, rdllink) { |
37b5e5212 epoll: remove ep_... |
861 |
if (ep_item_poll(epi, &pt, depth)) { |
a9a08845e vfs: do bulk POLL... |
862 |
return EPOLLIN | EPOLLRDNORM; |
37b5e5212 epoll: remove ep_... |
863 |
} else { |
5071f97ec epoll: fix epoll'... |
864 865 866 867 868 |
/* * Item has been dropped into the ready list by the poll * callback, but it's not actually ready, as far as * caller requested events goes. We can remove it here. */ |
eea1d5859 epoll: use RCU to... |
869 |
__pm_relax(ep_wakeup_source(epi)); |
5071f97ec epoll: fix epoll'... |
870 |
list_del_init(&epi->rdllink); |
296e236e9 epoll: fix epoll'... |
871 |
} |
5071f97ec epoll: fix epoll'... |
872 873 874 875 |
} return 0; } |
a11e1d432 Revert changes to... |
876 |
static __poll_t ep_eventpoll_poll(struct file *file, poll_table *wait) |
11c5ad0ec eventpoll: switch... |
877 878 879 |
{ struct eventpoll *ep = file->private_data; int depth = 0; |
7699acd13 epoll cleanups: e... |
880 |
|
a11e1d432 Revert changes to... |
881 882 |
/* Insert inside our poll wait queue */ poll_wait(file, &ep->poll_wait, wait); |
5071f97ec epoll: fix epoll'... |
883 884 |
/* * Proceed to find out if wanted events are really available inside |
37b5e5212 epoll: remove ep_... |
885 |
* the ready list. |
5071f97ec epoll: fix epoll'... |
886 |
*/ |
37b5e5212 epoll: remove ep_... |
887 888 |
return ep_scan_ready_list(ep, ep_read_events_proc, &depth, depth, false); |
7699acd13 epoll cleanups: e... |
889 |
} |
138d22b58 fs, epoll: add pr... |
890 |
#ifdef CONFIG_PROC_FS |
a3816ab0e fs: Convert show_... |
891 |
static void ep_show_fdinfo(struct seq_file *m, struct file *f) |
138d22b58 fs, epoll: add pr... |
892 893 894 |
{ struct eventpoll *ep = f->private_data; struct rb_node *rbp; |
138d22b58 fs, epoll: add pr... |
895 896 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
897 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
138d22b58 fs, epoll: add pr... |
898 |
struct epitem *epi = rb_entry(rbp, struct epitem, rbn); |
77493f04b procfs: fdinfo: e... |
899 |
struct inode *inode = file_inode(epi->ffd.file); |
138d22b58 fs, epoll: add pr... |
900 |
|
77493f04b procfs: fdinfo: e... |
901 902 903 |
seq_printf(m, "tfd: %8d events: %8x data: %16llx " " pos:%lli ino:%lx sdev:%x ", |
a3816ab0e fs: Convert show_... |
904 |
epi->ffd.fd, epi->event.events, |
77493f04b procfs: fdinfo: e... |
905 906 907 |
(long long)epi->event.data, (long long)epi->ffd.file->f_pos, inode->i_ino, inode->i_sb->s_dev); |
a3816ab0e fs: Convert show_... |
908 |
if (seq_has_overflowed(m)) |
138d22b58 fs, epoll: add pr... |
909 910 911 |
break; } mutex_unlock(&ep->mtx); |
138d22b58 fs, epoll: add pr... |
912 913 |
} #endif |
7699acd13 epoll cleanups: e... |
914 915 |
/* File callbacks that implement the eventpoll file behaviour */ static const struct file_operations eventpoll_fops = { |
138d22b58 fs, epoll: add pr... |
916 917 918 |
#ifdef CONFIG_PROC_FS .show_fdinfo = ep_show_fdinfo, #endif |
7699acd13 epoll cleanups: e... |
919 |
.release = ep_eventpoll_release, |
a11e1d432 Revert changes to... |
920 |
.poll = ep_eventpoll_poll, |
6038f373a llseek: automatic... |
921 |
.llseek = noop_llseek, |
7699acd13 epoll cleanups: e... |
922 |
}; |
b611967de [PATCH] epoll_pwa... |
923 |
/* |
7699acd13 epoll cleanups: e... |
924 925 926 |
* This is called from eventpoll_release() to unlink files from the eventpoll * interface. We need to have this facility to cleanup correctly files that are * closed without being removed from the eventpoll interface. |
b611967de [PATCH] epoll_pwa... |
927 |
*/ |
7699acd13 epoll cleanups: e... |
928 |
void eventpoll_release_file(struct file *file) |
b611967de [PATCH] epoll_pwa... |
929 |
{ |
7699acd13 epoll cleanups: e... |
930 |
struct eventpoll *ep; |
ebe06187b epoll: fix use-af... |
931 |
struct epitem *epi, *next; |
b611967de [PATCH] epoll_pwa... |
932 933 |
/* |
684999149 Rename struct fil... |
934 |
* We don't want to get "file->f_lock" because it is not |
7699acd13 epoll cleanups: e... |
935 |
* necessary. It is not necessary because we're in the "struct file" |
25985edce Fix common misspe... |
936 |
* cleanup path, and this means that no one is using this file anymore. |
5071f97ec epoll: fix epoll'... |
937 |
* So, for example, epoll_ctl() cannot hit here since if we reach this |
67647d0fb epoll: fix some c... |
938 |
* point, the file counter already went to zero and fget() would fail. |
d47de16c7 fix epoll single ... |
939 |
* The only hit might come from ep_free() but by holding the mutex |
7699acd13 epoll cleanups: e... |
940 |
* will correctly serialize the operation. We do need to acquire |
d47de16c7 fix epoll single ... |
941 |
* "ep->mtx" after "epmutex" because ep_remove() requires it when called |
7699acd13 epoll cleanups: e... |
942 |
* from anywhere but ep_free(). |
684999149 Rename struct fil... |
943 944 |
* * Besides, ep_remove() acquires the lock, so we can't hold it here. |
b611967de [PATCH] epoll_pwa... |
945 |
*/ |
7699acd13 epoll cleanups: e... |
946 |
mutex_lock(&epmutex); |
ebe06187b epoll: fix use-af... |
947 |
list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) { |
7699acd13 epoll cleanups: e... |
948 |
ep = epi->ep; |
d8805e633 epoll: fix spurio... |
949 |
mutex_lock_nested(&ep->mtx, 0); |
7699acd13 epoll cleanups: e... |
950 |
ep_remove(ep, epi); |
d47de16c7 fix epoll single ... |
951 |
mutex_unlock(&ep->mtx); |
b611967de [PATCH] epoll_pwa... |
952 |
} |
7699acd13 epoll cleanups: e... |
953 |
mutex_unlock(&epmutex); |
b611967de [PATCH] epoll_pwa... |
954 |
} |
53d2be79d [PATCH] epoll: fi... |
955 |
static int ep_alloc(struct eventpoll **pep) |
1da177e4c Linux-2.6.12-rc2 |
956 |
{ |
7ef9964e6 epoll: introduce ... |
957 958 959 |
int error; struct user_struct *user; struct eventpoll *ep; |
1da177e4c Linux-2.6.12-rc2 |
960 |
|
7ef9964e6 epoll: introduce ... |
961 |
user = get_current_user(); |
7ef9964e6 epoll: introduce ... |
962 963 964 965 |
error = -ENOMEM; ep = kzalloc(sizeof(*ep), GFP_KERNEL); if (unlikely(!ep)) goto free_uid; |
1da177e4c Linux-2.6.12-rc2 |
966 |
|
d47de16c7 fix epoll single ... |
967 |
mutex_init(&ep->mtx); |
a218cc491 epoll: use rwlock... |
968 |
rwlock_init(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
969 970 971 |
init_waitqueue_head(&ep->wq); init_waitqueue_head(&ep->poll_wait); INIT_LIST_HEAD(&ep->rdllist); |
b2ac2ea62 fs/epoll: use fas... |
972 |
ep->rbr = RB_ROOT_CACHED; |
d47de16c7 fix epoll single ... |
973 |
ep->ovflist = EP_UNACTIVE_PTR; |
7ef9964e6 epoll: introduce ... |
974 |
ep->user = user; |
1da177e4c Linux-2.6.12-rc2 |
975 |
|
53d2be79d [PATCH] epoll: fi... |
976 |
*pep = ep; |
1da177e4c Linux-2.6.12-rc2 |
977 |
|
1da177e4c Linux-2.6.12-rc2 |
978 |
return 0; |
7ef9964e6 epoll: introduce ... |
979 980 981 982 |
free_uid: free_uid(user); return error; |
1da177e4c Linux-2.6.12-rc2 |
983 |
} |
1da177e4c Linux-2.6.12-rc2 |
984 |
/* |
c7ea76302 epoll locks chang... |
985 986 987 |
* Search the file inside the eventpoll tree. The RB tree operations * are protected by the "mtx" mutex, and ep_find() must be called with * "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
988 989 990 991 |
*/ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) { int kcmp; |
1da177e4c Linux-2.6.12-rc2 |
992 993 994 |
struct rb_node *rbp; struct epitem *epi, *epir = NULL; struct epoll_filefd ffd; |
b030a4dd6 [PATCH] Remove ev... |
995 |
ep_set_ffd(&ffd, file, fd); |
b2ac2ea62 fs/epoll: use fas... |
996 |
for (rbp = ep->rbr.rb_root.rb_node; rbp; ) { |
1da177e4c Linux-2.6.12-rc2 |
997 |
epi = rb_entry(rbp, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
998 |
kcmp = ep_cmp_ffd(&ffd, &epi->ffd); |
1da177e4c Linux-2.6.12-rc2 |
999 1000 1001 1002 1003 |
if (kcmp > 0) rbp = rbp->rb_right; else if (kcmp < 0) rbp = rbp->rb_left; else { |
1da177e4c Linux-2.6.12-rc2 |
1004 1005 1006 1007 |
epir = epi; break; } } |
1da177e4c Linux-2.6.12-rc2 |
1008 |
|
1da177e4c Linux-2.6.12-rc2 |
1009 1010 |
return epir; } |
92ef6da3d kcmp: fs/epoll: w... |
1011 |
#ifdef CONFIG_CHECKPOINT_RESTORE |
0791e3644 kcmp: add KCMP_EP... |
1012 1013 1014 1015 |
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff) { struct rb_node *rbp; struct epitem *epi; |
b2ac2ea62 fs/epoll: use fas... |
1016 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
0791e3644 kcmp: add KCMP_EP... |
1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 |
epi = rb_entry(rbp, struct epitem, rbn); if (epi->ffd.fd == tfd) { if (toff == 0) return epi; else toff--; } cond_resched(); } return NULL; } struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff) { struct file *file_raw; struct eventpoll *ep; struct epitem *epi; if (!is_file_epoll(file)) return ERR_PTR(-EINVAL); ep = file->private_data; mutex_lock(&ep->mtx); epi = ep_find_tfd(ep, tfd, toff); if (epi) file_raw = epi->ffd.file; else file_raw = ERR_PTR(-ENOENT); mutex_unlock(&ep->mtx); return file_raw; } |
92ef6da3d kcmp: fs/epoll: w... |
1052 |
#endif /* CONFIG_CHECKPOINT_RESTORE */ |
0791e3644 kcmp: add KCMP_EP... |
1053 |
|
a218cc491 epoll: use rwlock... |
1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 |
/** * Adds a new entry to the tail of the list in a lockless way, i.e. * multiple CPUs are allowed to call this function concurrently. * * Beware: it is necessary to prevent any other modifications of the * existing list until all changes are completed, in other words * concurrent list_add_tail_lockless() calls should be protected * with a read lock, where write lock acts as a barrier which * makes sure all list_add_tail_lockless() calls are fully * completed. * * Also an element can be locklessly added to the list only in one * direction i.e. either to the tail either to the head, otherwise * concurrent access will corrupt the list. * * Returns %false if element has been already added to the list, %true * otherwise. */ static inline bool list_add_tail_lockless(struct list_head *new, struct list_head *head) { struct list_head *prev; /* * This is simple 'new->next = head' operation, but cmpxchg() * is used in order to detect that same element has been just * added to the list from another CPU: the winner observes * new->next == new. */ if (cmpxchg(&new->next, new, head) != new) return false; /* * Initially ->next of a new element must be updated with the head * (we are inserting to the tail) and only then pointers are atomically * exchanged. XCHG guarantees memory ordering, thus ->next should be * updated before pointers are actually swapped and pointers are * swapped before prev->next is updated. */ prev = xchg(&head->prev, new); /* * It is safe to modify prev->next and new->prev, because a new element * is added only to the tail and new->next is updated before XCHG. */ prev->next = new; new->prev = prev; return true; } /** * Chains a new epi entry to the tail of the ep->ovflist in a lockless way, * i.e. multiple CPUs are allowed to call this function concurrently. * * Returns %false if epi element has been already chained, %true otherwise. */ static inline bool chain_epi_lockless(struct epitem *epi) { struct eventpoll *ep = epi->ep; |
0c54a6a44 eventpoll: fix mi... |
1116 1117 1118 |
/* Fast preliminary check */ if (epi->next != EP_UNACTIVE_PTR) return false; |
a218cc491 epoll: use rwlock... |
1119 1120 1121 1122 1123 1124 1125 1126 1127 |
/* Check that the same epi has not been just chained from another CPU */ if (cmpxchg(&epi->next, EP_UNACTIVE_PTR, NULL) != EP_UNACTIVE_PTR) return false; /* Atomically exchange tail */ epi->next = xchg(&ep->ovflist, epi); return true; } |
1da177e4c Linux-2.6.12-rc2 |
1128 |
/* |
7699acd13 epoll cleanups: e... |
1129 |
* This is the callback that is passed to the wait queue wakeup |
bf6a41db7 fs/eventpoll.c: f... |
1130 |
* mechanism. It is called by the stored file descriptors when they |
7699acd13 epoll cleanups: e... |
1131 |
* have events to report. |
a218cc491 epoll: use rwlock... |
1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 |
* * This callback takes a read lock in order not to content with concurrent * events from another file descriptors, thus all modifications to ->rdllist * or ->ovflist are lockless. Read lock is paired with the write lock from * ep_scan_ready_list(), which stops all list modifications and guarantees * that lists state is seen correctly. * * Another thing worth to mention is that ep_poll_callback() can be called * concurrently for the same @epi from different CPUs if poll table was inited * with several wait queues entries. Plural wakeup from different CPUs of a * single wait queue is serialized by wq.lock, but the case when multiple wait * queues are used should be detected accordingly. This is detected using * cmpxchg() operation. |
1da177e4c Linux-2.6.12-rc2 |
1145 |
*/ |
ac6424b98 sched/wait: Renam... |
1146 |
static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
1da177e4c Linux-2.6.12-rc2 |
1147 |
{ |
7699acd13 epoll cleanups: e... |
1148 |
int pwake = 0; |
7699acd13 epoll cleanups: e... |
1149 1150 |
struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; |
3ad6f93e9 annotate poll-rel... |
1151 |
__poll_t pollflags = key_to_poll(key); |
a218cc491 epoll: use rwlock... |
1152 |
unsigned long flags; |
df0108c5d epoll: add EPOLLE... |
1153 |
int ewake = 0; |
1da177e4c Linux-2.6.12-rc2 |
1154 |
|
a218cc491 epoll: use rwlock... |
1155 |
read_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1156 |
|
bf3b9f637 epoll: Add busy p... |
1157 |
ep_set_busy_poll_napi_id(epi); |
7699acd13 epoll cleanups: e... |
1158 1159 1160 1161 1162 1163 1164 |
/* * If the event mask does not contain any poll(2) event, we consider the * descriptor to be disabled. This condition is likely the effect of the * EPOLLONESHOT bit that disables the descriptor when an event is received, * until the next EPOLL_CTL_MOD will be issued. */ if (!(epi->event.events & ~EP_PRIVATE_BITS)) |
d47de16c7 fix epoll single ... |
1165 1166 1167 |
goto out_unlock; /* |
2dfa4eeab epoll keyed wakeu... |
1168 1169 1170 1171 1172 |
* Check the events coming with the callback. At this stage, not * every device reports the events in the "key" parameter of the * callback. We need to be able to handle both cases here, hence the * test for "key" != NULL before the event match test. */ |
3ad6f93e9 annotate poll-rel... |
1173 |
if (pollflags && !(pollflags & epi->event.events)) |
2dfa4eeab epoll keyed wakeu... |
1174 1175 1176 |
goto out_unlock; /* |
bf6a41db7 fs/eventpoll.c: f... |
1177 |
* If we are transferring events to userspace, we can hold no locks |
d47de16c7 fix epoll single ... |
1178 |
* (because we're accessing user memory, and because of linux f_op->poll() |
bf6a41db7 fs/eventpoll.c: f... |
1179 |
* semantics). All the events that happen during that period of time are |
d47de16c7 fix epoll single ... |
1180 1181 |
* chained in ep->ovflist and requeued later on. */ |
c5a282e96 fs/epoll: reduce ... |
1182 |
if (READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR) { |
0c54a6a44 eventpoll: fix mi... |
1183 1184 1185 1186 1187 |
if (chain_epi_lockless(epi)) ep_pm_stay_awake_rcu(epi); } else if (!ep_is_linked(epi)) { /* In the usual case, add event to ready list. */ if (list_add_tail_lockless(&epi->rdllink, &ep->rdllist)) |
c3e320b61 epoll: unify awak... |
1188 |
ep_pm_stay_awake_rcu(epi); |
4d7e30d98 epoll: Add a flag... |
1189 |
} |
7699acd13 epoll cleanups: e... |
1190 |
|
7699acd13 epoll cleanups: e... |
1191 1192 1193 1194 |
/* * Wake up ( if active ) both the eventpoll wait list and the ->poll() * wait list. */ |
df0108c5d epoll: add EPOLLE... |
1195 |
if (waitqueue_active(&ep->wq)) { |
b6a515c8a epoll: restrict E... |
1196 |
if ((epi->event.events & EPOLLEXCLUSIVE) && |
3ad6f93e9 annotate poll-rel... |
1197 1198 |
!(pollflags & POLLFREE)) { switch (pollflags & EPOLLINOUT_BITS) { |
a9a08845e vfs: do bulk POLL... |
1199 1200 |
case EPOLLIN: if (epi->event.events & EPOLLIN) |
b6a515c8a epoll: restrict E... |
1201 1202 |
ewake = 1; break; |
a9a08845e vfs: do bulk POLL... |
1203 1204 |
case EPOLLOUT: if (epi->event.events & EPOLLOUT) |
b6a515c8a epoll: restrict E... |
1205 1206 1207 1208 1209 1210 1211 |
ewake = 1; break; case 0: ewake = 1; break; } } |
a218cc491 epoll: use rwlock... |
1212 |
wake_up(&ep->wq); |
df0108c5d epoll: add EPOLLE... |
1213 |
} |
7699acd13 epoll cleanups: e... |
1214 1215 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
d47de16c7 fix epoll single ... |
1216 |
out_unlock: |
a218cc491 epoll: use rwlock... |
1217 |
read_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1218 |
|
7699acd13 epoll cleanups: e... |
1219 1220 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1221 |
ep_poll_safewake(ep, epi); |
7699acd13 epoll cleanups: e... |
1222 |
|
138e4ad67 epoll: fix race b... |
1223 1224 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) ewake = 1; |
3ad6f93e9 annotate poll-rel... |
1225 |
if (pollflags & POLLFREE) { |
138e4ad67 epoll: fix race b... |
1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 |
/* * If we race with ep_remove_wait_queue() it can miss * ->whead = NULL and do another remove_wait_queue() after * us, so we can't use __remove_wait_queue(). */ list_del_init(&wait->entry); /* * ->whead != NULL protects us from the race with ep_free() * or ep_remove(), ep_remove_wait_queue() takes whead->lock * held by the caller. Once we nullify it, nothing protects * ep/epi or even wait. */ smp_store_release(&ep_pwq_from_wait(wait)->whead, NULL); } |
df0108c5d epoll: add EPOLLE... |
1240 |
|
138e4ad67 epoll: fix race b... |
1241 |
return ewake; |
7699acd13 epoll cleanups: e... |
1242 |
} |
1da177e4c Linux-2.6.12-rc2 |
1243 1244 1245 1246 1247 1248 1249 1250 |
/* * This is the callback that is used to add our wait queue to the * target file wakeup lists. */ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, poll_table *pt) { |
b030a4dd6 [PATCH] Remove ev... |
1251 |
struct epitem *epi = ep_item_from_epqueue(pt); |
1da177e4c Linux-2.6.12-rc2 |
1252 |
struct eppoll_entry *pwq; |
e94b17660 [PATCH] slab: rem... |
1253 |
if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL))) { |
1da177e4c Linux-2.6.12-rc2 |
1254 1255 1256 |
init_waitqueue_func_entry(&pwq->wait, ep_poll_callback); pwq->whead = whead; pwq->base = epi; |
df0108c5d epoll: add EPOLLE... |
1257 1258 1259 1260 |
if (epi->event.events & EPOLLEXCLUSIVE) add_wait_queue_exclusive(whead, &pwq->wait); else add_wait_queue(whead, &pwq->wait); |
1da177e4c Linux-2.6.12-rc2 |
1261 1262 |
list_add_tail(&pwq->llink, &epi->pwqlist); epi->nwait++; |
296e236e9 epoll: fix epoll'... |
1263 |
} else { |
1da177e4c Linux-2.6.12-rc2 |
1264 1265 |
/* We have to signal that an error occurred */ epi->nwait = -1; |
296e236e9 epoll: fix epoll'... |
1266 |
} |
1da177e4c Linux-2.6.12-rc2 |
1267 |
} |
1da177e4c Linux-2.6.12-rc2 |
1268 1269 1270 |
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) { int kcmp; |
b2ac2ea62 fs/epoll: use fas... |
1271 |
struct rb_node **p = &ep->rbr.rb_root.rb_node, *parent = NULL; |
1da177e4c Linux-2.6.12-rc2 |
1272 |
struct epitem *epic; |
b2ac2ea62 fs/epoll: use fas... |
1273 |
bool leftmost = true; |
1da177e4c Linux-2.6.12-rc2 |
1274 1275 1276 1277 |
while (*p) { parent = *p; epic = rb_entry(parent, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
1278 |
kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd); |
b2ac2ea62 fs/epoll: use fas... |
1279 |
if (kcmp > 0) { |
1da177e4c Linux-2.6.12-rc2 |
1280 |
p = &parent->rb_right; |
b2ac2ea62 fs/epoll: use fas... |
1281 1282 |
leftmost = false; } else |
1da177e4c Linux-2.6.12-rc2 |
1283 1284 1285 |
p = &parent->rb_left; } rb_link_node(&epi->rbn, parent, p); |
b2ac2ea62 fs/epoll: use fas... |
1286 |
rb_insert_color_cached(&epi->rbn, &ep->rbr, leftmost); |
1da177e4c Linux-2.6.12-rc2 |
1287 |
} |
a80a6b85b revert "epoll: su... |
1288 |
|
28d82dc1c epoll: limit paths |
1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 |
#define PATH_ARR_SIZE 5 /* * These are the number paths of length 1 to 5, that we are allowing to emanate * from a single file of interest. For example, we allow 1000 paths of length * 1, to emanate from each file of interest. This essentially represents the * potential wakeup paths, which need to be limited in order to avoid massive * uncontrolled wakeup storms. The common use case should be a single ep which * is connected to n file sources. In this case each file source has 1 path * of length 1. Thus, the numbers below should be more than sufficient. These * path limits are enforced during an EPOLL_CTL_ADD operation, since a modify * and delete can't add additional paths. Protected by the epmutex. */ static const int path_limits[PATH_ARR_SIZE] = { 1000, 500, 100, 50, 10 }; static int path_count[PATH_ARR_SIZE]; static int path_count_inc(int nests) { |
93dc6107a Don't limit non-n... |
1306 1307 1308 |
/* Allow an arbitrary number of depth 1 paths */ if (nests == 0) return 0; |
28d82dc1c epoll: limit paths |
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 |
if (++path_count[nests] > path_limits[nests]) return -1; return 0; } static void path_count_init(void) { int i; for (i = 0; i < PATH_ARR_SIZE; i++) path_count[i] = 0; } static int reverse_path_check_proc(void *priv, void *cookie, int call_nests) { int error = 0; struct file *file = priv; struct file *child_file; struct epitem *epi; |
ae10b2b4e epoll: optimize E... |
1328 1329 1330 |
/* CTL_DEL can remove links here, but that can't increase our count */ rcu_read_lock(); list_for_each_entry_rcu(epi, &file->f_ep_links, fllink) { |
28d82dc1c epoll: limit paths |
1331 1332 1333 1334 1335 1336 1337 1338 1339 |
child_file = epi->ep->file; if (is_file_epoll(child_file)) { if (list_empty(&child_file->f_ep_links)) { if (path_count_inc(call_nests)) { error = -1; break; } } else { error = ep_call_nested(&poll_loop_ncalls, |
28d82dc1c epoll: limit paths |
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 |
reverse_path_check_proc, child_file, child_file, current); } if (error != 0) break; } else { printk(KERN_ERR "reverse_path_check_proc: " "file is not an ep! "); } } |
ae10b2b4e epoll: optimize E... |
1352 |
rcu_read_unlock(); |
28d82dc1c epoll: limit paths |
1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 |
return error; } /** * reverse_path_check - The tfile_check_list is list of file *, which have * links that are proposed to be newly added. We need to * make sure that those added links don't add too many * paths such that we will spend all our time waking up * eventpoll objects. * * Returns: Returns zero if the proposed links don't create too many paths, * -1 otherwise. */ static int reverse_path_check(void) { |
28d82dc1c epoll: limit paths |
1368 1369 1370 1371 1372 |
int error = 0; struct file *current_file; /* let's call this for all tfiles */ list_for_each_entry(current_file, &tfile_check_list, f_tfile_llink) { |
28d82dc1c epoll: limit paths |
1373 |
path_count_init(); |
74bdc1298 fs/epoll: remove ... |
1374 |
error = ep_call_nested(&poll_loop_ncalls, |
28d82dc1c epoll: limit paths |
1375 1376 1377 1378 1379 1380 1381 |
reverse_path_check_proc, current_file, current_file, current); if (error) break; } return error; } |
4d7e30d98 epoll: Add a flag... |
1382 1383 |
static int ep_create_wakeup_source(struct epitem *epi) { |
3701cb59d ep_create_wakeup_... |
1384 |
struct name_snapshot n; |
eea1d5859 epoll: use RCU to... |
1385 |
struct wakeup_source *ws; |
4d7e30d98 epoll: Add a flag... |
1386 1387 |
if (!epi->ep->ws) { |
c8377adfa PM / wakeup: Show... |
1388 |
epi->ep->ws = wakeup_source_register(NULL, "eventpoll"); |
4d7e30d98 epoll: Add a flag... |
1389 1390 1391 |
if (!epi->ep->ws) return -ENOMEM; } |
3701cb59d ep_create_wakeup_... |
1392 1393 1394 |
take_dentry_name_snapshot(&n, epi->ffd.file->f_path.dentry); ws = wakeup_source_register(NULL, n.name.name); release_dentry_name_snapshot(&n); |
eea1d5859 epoll: use RCU to... |
1395 1396 |
if (!ws) |
4d7e30d98 epoll: Add a flag... |
1397 |
return -ENOMEM; |
eea1d5859 epoll: use RCU to... |
1398 |
rcu_assign_pointer(epi->ws, ws); |
4d7e30d98 epoll: Add a flag... |
1399 1400 1401 |
return 0; } |
eea1d5859 epoll: use RCU to... |
1402 1403 |
/* rare code path, only used when EPOLL_CTL_MOD removes a wakeup source */ static noinline void ep_destroy_wakeup_source(struct epitem *epi) |
4d7e30d98 epoll: Add a flag... |
1404 |
{ |
eea1d5859 epoll: use RCU to... |
1405 |
struct wakeup_source *ws = ep_wakeup_source(epi); |
d6d67e723 epoll: cleanup: u... |
1406 |
RCU_INIT_POINTER(epi->ws, NULL); |
eea1d5859 epoll: use RCU to... |
1407 1408 1409 1410 1411 1412 1413 1414 |
/* * wait for ep_pm_stay_awake_rcu to finish, synchronize_rcu is * used internally by wakeup_source_remove, too (called by * wakeup_source_unregister), so we cannot use call_rcu */ synchronize_rcu(); wakeup_source_unregister(ws); |
4d7e30d98 epoll: Add a flag... |
1415 |
} |
c7ea76302 epoll locks chang... |
1416 1417 1418 |
/* * Must be called with "mtx" held. */ |
bec1a502d eventpoll: consti... |
1419 |
static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, |
67347fe4e epoll: do not tak... |
1420 |
struct file *tfile, int fd, int full_check) |
1da177e4c Linux-2.6.12-rc2 |
1421 |
{ |
d85e2aa2e annotate ep_scan_... |
1422 1423 |
int error, pwake = 0; __poll_t revents; |
52bd19f76 epoll: convert ma... |
1424 |
long user_watches; |
1da177e4c Linux-2.6.12-rc2 |
1425 1426 |
struct epitem *epi; struct ep_pqueue epq; |
92e641784 s/epoll: robustif... |
1427 |
lockdep_assert_irqs_enabled(); |
52bd19f76 epoll: convert ma... |
1428 1429 |
user_watches = atomic_long_read(&ep->user->epoll_watches); if (unlikely(user_watches >= max_user_watches)) |
7ef9964e6 epoll: introduce ... |
1430 |
return -ENOSPC; |
e94b17660 [PATCH] slab: rem... |
1431 |
if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) |
7ef9964e6 epoll: introduce ... |
1432 |
return -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1433 1434 |
/* Item initialization follow here ... */ |
1da177e4c Linux-2.6.12-rc2 |
1435 1436 |
INIT_LIST_HEAD(&epi->rdllink); INIT_LIST_HEAD(&epi->fllink); |
1da177e4c Linux-2.6.12-rc2 |
1437 1438 |
INIT_LIST_HEAD(&epi->pwqlist); epi->ep = ep; |
b030a4dd6 [PATCH] Remove ev... |
1439 |
ep_set_ffd(&epi->ffd, tfile, fd); |
1da177e4c Linux-2.6.12-rc2 |
1440 |
epi->event = *event; |
1da177e4c Linux-2.6.12-rc2 |
1441 |
epi->nwait = 0; |
d47de16c7 fix epoll single ... |
1442 |
epi->next = EP_UNACTIVE_PTR; |
4d7e30d98 epoll: Add a flag... |
1443 1444 1445 1446 1447 |
if (epi->event.events & EPOLLWAKEUP) { error = ep_create_wakeup_source(epi); if (error) goto error_create_wakeup_source; } else { |
eea1d5859 epoll: use RCU to... |
1448 |
RCU_INIT_POINTER(epi->ws, NULL); |
4d7e30d98 epoll: Add a flag... |
1449 |
} |
1da177e4c Linux-2.6.12-rc2 |
1450 |
|
f8d4f44df epoll: do not ins... |
1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 |
/* Add the current item to the list of active epoll hook for this file */ spin_lock(&tfile->f_lock); list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); spin_unlock(&tfile->f_lock); /* * Add the current item to the RB tree. All RB tree operations are * protected by "mtx", and ep_insert() is called with "mtx" held. */ ep_rbtree_insert(ep, epi); /* now check if we've created too many backpaths */ error = -EINVAL; if (full_check && reverse_path_check()) goto error_remove_epi; |
1da177e4c Linux-2.6.12-rc2 |
1466 1467 1468 1469 1470 1471 1472 |
/* Initialize the poll table using the queue callback */ epq.epi = epi; init_poll_funcptr(&epq.pt, ep_ptable_queue_proc); /* * Attach the item to the poll hooks and get current event bits. * We can safely use the file* here because its usage count has |
c7ea76302 epoll locks chang... |
1473 1474 1475 |
* been increased by the caller of this function. Note that after * this operation completes, the poll callback can start hitting * the new item. |
1da177e4c Linux-2.6.12-rc2 |
1476 |
*/ |
37b5e5212 epoll: remove ep_... |
1477 |
revents = ep_item_poll(epi, &epq.pt, 1); |
1da177e4c Linux-2.6.12-rc2 |
1478 1479 1480 1481 1482 1483 |
/* * We have to check if something went wrong during the poll wait queue * install process. Namely an allocation for a wait queue failed due * high memory pressure. */ |
7ef9964e6 epoll: introduce ... |
1484 |
error = -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1485 |
if (epi->nwait < 0) |
7699acd13 epoll cleanups: e... |
1486 |
goto error_unregister; |
1da177e4c Linux-2.6.12-rc2 |
1487 |
|
c7ea76302 epoll locks chang... |
1488 |
/* We have to drop the new item inside our item list to keep track of it */ |
a218cc491 epoll: use rwlock... |
1489 |
write_lock_irq(&ep->lock); |
c7ea76302 epoll locks chang... |
1490 |
|
bf3b9f637 epoll: Add busy p... |
1491 1492 |
/* record NAPI ID of new item if present */ ep_set_busy_poll_napi_id(epi); |
1da177e4c Linux-2.6.12-rc2 |
1493 |
/* If the file is already "ready" we drop it inside the ready list */ |
992991c03 fs/eventpoll.c: s... |
1494 |
if (revents && !ep_is_linked(epi)) { |
1da177e4c Linux-2.6.12-rc2 |
1495 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1496 |
ep_pm_stay_awake(epi); |
1da177e4c Linux-2.6.12-rc2 |
1497 1498 1499 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
a218cc491 epoll: use rwlock... |
1500 |
wake_up(&ep->wq); |
1da177e4c Linux-2.6.12-rc2 |
1501 1502 1503 |
if (waitqueue_active(&ep->poll_wait)) pwake++; } |
a218cc491 epoll: use rwlock... |
1504 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1505 |
|
52bd19f76 epoll: convert ma... |
1506 |
atomic_long_inc(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
1507 |
|
1da177e4c Linux-2.6.12-rc2 |
1508 1509 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1510 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1511 |
|
1da177e4c Linux-2.6.12-rc2 |
1512 |
return 0; |
f8d4f44df epoll: do not ins... |
1513 1514 |
error_unregister: ep_unregister_pollwait(ep, epi); |
28d82dc1c epoll: limit paths |
1515 1516 |
error_remove_epi: spin_lock(&tfile->f_lock); |
ae10b2b4e epoll: optimize E... |
1517 |
list_del_rcu(&epi->fllink); |
28d82dc1c epoll: limit paths |
1518 |
spin_unlock(&tfile->f_lock); |
b2ac2ea62 fs/epoll: use fas... |
1519 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
28d82dc1c epoll: limit paths |
1520 |
|
1da177e4c Linux-2.6.12-rc2 |
1521 1522 |
/* * We need to do this because an event could have been arrived on some |
67647d0fb epoll: fix some c... |
1523 1524 1525 |
* allocated wait queue. Note that we don't care about the ep->ovflist * list, since that is used/cleaned only inside a section bound by "mtx". * And ep_insert() is called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1526 |
*/ |
a218cc491 epoll: use rwlock... |
1527 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
1528 |
if (ep_is_linked(epi)) |
6192bd536 epoll: optimizati... |
1529 |
list_del_init(&epi->rdllink); |
a218cc491 epoll: use rwlock... |
1530 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1531 |
|
eea1d5859 epoll: use RCU to... |
1532 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
4d7e30d98 epoll: Add a flag... |
1533 1534 |
error_create_wakeup_source: |
b030a4dd6 [PATCH] Remove ev... |
1535 |
kmem_cache_free(epi_cache, epi); |
7ef9964e6 epoll: introduce ... |
1536 |
|
1da177e4c Linux-2.6.12-rc2 |
1537 1538 |
return error; } |
1da177e4c Linux-2.6.12-rc2 |
1539 1540 |
/* * Modify the interest event mask by dropping an event if the new mask |
c7ea76302 epoll locks chang... |
1541 |
* has a match in the current file status. Must be called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1542 |
*/ |
bec1a502d eventpoll: consti... |
1543 1544 |
static int ep_modify(struct eventpoll *ep, struct epitem *epi, const struct epoll_event *event) |
1da177e4c Linux-2.6.12-rc2 |
1545 1546 |
{ int pwake = 0; |
626cf2366 poll: add poll_re... |
1547 |
poll_table pt; |
92e641784 s/epoll: robustif... |
1548 |
lockdep_assert_irqs_enabled(); |
626cf2366 poll: add poll_re... |
1549 |
init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1550 1551 |
/* |
e057e15ff epoll: clean up e... |
1552 1553 1554 |
* Set the new event interest mask before calling f_op->poll(); * otherwise we might miss an event that happens between the * f_op->poll() call and the new event set registering. |
1da177e4c Linux-2.6.12-rc2 |
1555 |
*/ |
128dd1759 epoll: prevent mi... |
1556 |
epi->event.events = event->events; /* need barrier below */ |
e057e15ff epoll: clean up e... |
1557 |
epi->event.data = event->data; /* protected by mtx */ |
4d7e30d98 epoll: Add a flag... |
1558 |
if (epi->event.events & EPOLLWAKEUP) { |
eea1d5859 epoll: use RCU to... |
1559 |
if (!ep_has_wakeup_source(epi)) |
4d7e30d98 epoll: Add a flag... |
1560 |
ep_create_wakeup_source(epi); |
eea1d5859 epoll: use RCU to... |
1561 |
} else if (ep_has_wakeup_source(epi)) { |
4d7e30d98 epoll: Add a flag... |
1562 1563 |
ep_destroy_wakeup_source(epi); } |
1da177e4c Linux-2.6.12-rc2 |
1564 1565 |
/* |
128dd1759 epoll: prevent mi... |
1566 1567 1568 1569 1570 |
* The following barrier has two effects: * * 1) Flush epi changes above to other CPUs. This ensures * we do not miss events from ep_poll_callback if an * event occurs immediately after we call f_op->poll(). |
a218cc491 epoll: use rwlock... |
1571 |
* We need this because we did not take ep->lock while |
128dd1759 epoll: prevent mi... |
1572 |
* changing epi above (but ep_poll_callback does take |
a218cc491 epoll: use rwlock... |
1573 |
* ep->lock). |
128dd1759 epoll: prevent mi... |
1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 |
* * 2) We also need to ensure we do not miss _past_ events * when calling f_op->poll(). This barrier also * pairs with the barrier in wq_has_sleeper (see * comments for wq_has_sleeper). * * This barrier will now guarantee ep_poll_callback or f_op->poll * (or both) will notice the readiness of an item. */ smp_mb(); /* |
1da177e4c Linux-2.6.12-rc2 |
1586 1587 |
* Get current event bits. We can safely use the file* here because * its usage count has been increased by the caller of this function. |
c7ea76302 epoll locks chang... |
1588 |
* If the item is "hot" and it is not registered inside the ready |
67647d0fb epoll: fix some c... |
1589 |
* list, push it inside. |
1da177e4c Linux-2.6.12-rc2 |
1590 |
*/ |
69112736e eventpoll: no nee... |
1591 |
if (ep_item_poll(epi, &pt, 1)) { |
a218cc491 epoll: use rwlock... |
1592 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
1593 |
if (!ep_is_linked(epi)) { |
c7ea76302 epoll locks chang... |
1594 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1595 |
ep_pm_stay_awake(epi); |
c7ea76302 epoll locks chang... |
1596 1597 1598 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
a218cc491 epoll: use rwlock... |
1599 |
wake_up(&ep->wq); |
c7ea76302 epoll locks chang... |
1600 1601 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
7699acd13 epoll cleanups: e... |
1602 |
} |
a218cc491 epoll: use rwlock... |
1603 |
write_unlock_irq(&ep->lock); |
7699acd13 epoll cleanups: e... |
1604 |
} |
1da177e4c Linux-2.6.12-rc2 |
1605 |
|
7699acd13 epoll cleanups: e... |
1606 1607 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1608 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1609 |
|
7699acd13 epoll cleanups: e... |
1610 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1611 |
} |
d85e2aa2e annotate ep_scan_... |
1612 |
static __poll_t ep_send_events_proc(struct eventpoll *ep, struct list_head *head, |
296e236e9 epoll: fix epoll'... |
1613 |
void *priv) |
1da177e4c Linux-2.6.12-rc2 |
1614 |
{ |
5071f97ec epoll: fix epoll'... |
1615 |
struct ep_send_events_data *esed = priv; |
d85e2aa2e annotate ep_scan_... |
1616 |
__poll_t revents; |
4e0982a00 fs/epoll: simplif... |
1617 1618 |
struct epitem *epi, *tmp; struct epoll_event __user *uevent = esed->events; |
eea1d5859 epoll: use RCU to... |
1619 |
struct wakeup_source *ws; |
626cf2366 poll: add poll_re... |
1620 1621 1622 |
poll_table pt; init_poll_funcptr(&pt, NULL); |
4e0982a00 fs/epoll: simplif... |
1623 |
esed->res = 0; |
1da177e4c Linux-2.6.12-rc2 |
1624 |
|
296e236e9 epoll: fix epoll'... |
1625 |
/* |
5071f97ec epoll: fix epoll'... |
1626 1627 1628 |
* We can loop without lock because we are passed a task private list. * Items cannot vanish during the loop because ep_scan_ready_list() is * holding "mtx" during this call. |
296e236e9 epoll: fix epoll'... |
1629 |
*/ |
21877e1a5 fs/epoll: robusti... |
1630 |
lockdep_assert_held(&ep->mtx); |
4e0982a00 fs/epoll: simplif... |
1631 1632 1633 |
list_for_each_entry_safe(epi, tmp, head, rdllink) { if (esed->res >= esed->maxevents) break; |
d47de16c7 fix epoll single ... |
1634 |
|
4d7e30d98 epoll: Add a flag... |
1635 1636 1637 1638 1639 1640 1641 1642 1643 |
/* * Activate ep->ws before deactivating epi->ws to prevent * triggering auto-suspend here (in case we reactive epi->ws * below). * * This could be rearranged to delay the deactivation of epi->ws * instead, but then epi->ws would temporarily be out of sync * with ep_is_linked(). */ |
eea1d5859 epoll: use RCU to... |
1644 1645 1646 1647 1648 1649 |
ws = ep_wakeup_source(epi); if (ws) { if (ws->active) __pm_stay_awake(ep->ws); __pm_relax(ws); } |
d47de16c7 fix epoll single ... |
1650 |
list_del_init(&epi->rdllink); |
1da177e4c Linux-2.6.12-rc2 |
1651 |
|
296e236e9 epoll: fix epoll'... |
1652 |
/* |
5071f97ec epoll: fix epoll'... |
1653 1654 |
* If the event mask intersect the caller-requested one, * deliver the event to userspace. Again, ep_scan_ready_list() |
4e0982a00 fs/epoll: simplif... |
1655 |
* is holding ep->mtx, so no operations coming from userspace |
5071f97ec epoll: fix epoll'... |
1656 |
* can change the item. |
296e236e9 epoll: fix epoll'... |
1657 |
*/ |
4e0982a00 fs/epoll: simplif... |
1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 |
revents = ep_item_poll(epi, &pt, 1); if (!revents) continue; if (__put_user(revents, &uevent->events) || __put_user(epi->event.data, &uevent->data)) { list_add(&epi->rdllink, head); ep_pm_stay_awake(epi); if (!esed->res) esed->res = -EFAULT; return 0; } esed->res++; uevent++; if (epi->event.events & EPOLLONESHOT) epi->event.events &= EP_PRIVATE_BITS; else if (!(epi->event.events & EPOLLET)) { /* * If this file has been added with Level * Trigger mode, we need to insert back inside * the ready list, so that the next call to * epoll_wait() will check again the events * availability. At this point, no one can insert * into ep->rdllist besides us. The epoll_ctl() * callers are locked out by * ep_scan_ready_list() holding "mtx" and the * poll callback will queue them in ep->ovflist. */ list_add_tail(&epi->rdllink, &ep->rdllist); ep_pm_stay_awake(epi); |
296e236e9 epoll: fix epoll'... |
1688 1689 |
} } |
5071f97ec epoll: fix epoll'... |
1690 |
|
d7ebbe46f ep_send_events_pr... |
1691 |
return 0; |
5071f97ec epoll: fix epoll'... |
1692 |
} |
d47de16c7 fix epoll single ... |
1693 |
|
296e236e9 epoll: fix epoll'... |
1694 1695 |
static int ep_send_events(struct eventpoll *ep, struct epoll_event __user *events, int maxevents) |
5071f97ec epoll: fix epoll'... |
1696 1697 |
{ struct ep_send_events_data esed; |
1da177e4c Linux-2.6.12-rc2 |
1698 |
|
5071f97ec epoll: fix epoll'... |
1699 1700 |
esed.maxevents = maxevents; esed.events = events; |
6192bd536 epoll: optimizati... |
1701 |
|
d7ebbe46f ep_send_events_pr... |
1702 1703 |
ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false); return esed.res; |
1da177e4c Linux-2.6.12-rc2 |
1704 |
} |
766b9f928 fs: poll/select/r... |
1705 |
static inline struct timespec64 ep_set_mstimeout(long ms) |
0781b909b epoll: epoll_wait... |
1706 |
{ |
766b9f928 fs: poll/select/r... |
1707 |
struct timespec64 now, ts = { |
0781b909b epoll: epoll_wait... |
1708 1709 1710 |
.tv_sec = ms / MSEC_PER_SEC, .tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC), }; |
766b9f928 fs: poll/select/r... |
1711 1712 |
ktime_get_ts64(&now); return timespec64_add_safe(now, ts); |
0781b909b epoll: epoll_wait... |
1713 |
} |
f4d93ad74 epoll: fix compil... |
1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 |
/** * ep_poll - Retrieves ready events, and delivers them to the caller supplied * event buffer. * * @ep: Pointer to the eventpoll context. * @events: Pointer to the userspace buffer where the ready events should be * stored. * @maxevents: Size (in terms of number of events) of the caller event buffer. * @timeout: Maximum timeout for the ready events fetch operation, in * milliseconds. If the @timeout is zero, the function will not block, * while if the @timeout is less than zero, the function will block * until at least one event has been retrieved (or an error * occurred). * * Returns: Returns the number of ready events which have been fetched, or an * error code, in case of error. */ |
1da177e4c Linux-2.6.12-rc2 |
1731 1732 1733 |
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int maxevents, long timeout) { |
f4d93ad74 epoll: fix compil... |
1734 |
int res = 0, eavail, timed_out = 0; |
da8b44d5a timer: convert ti... |
1735 |
u64 slack = 0; |
ac6424b98 sched/wait: Renam... |
1736 |
wait_queue_entry_t wait; |
95aac7b1c epoll: make epoll... |
1737 |
ktime_t expires, *to = NULL; |
679abf381 fs/eventpoll.c: l... |
1738 |
lockdep_assert_irqs_enabled(); |
95aac7b1c epoll: make epoll... |
1739 |
if (timeout > 0) { |
766b9f928 fs: poll/select/r... |
1740 |
struct timespec64 end_time = ep_set_mstimeout(timeout); |
0781b909b epoll: epoll_wait... |
1741 |
|
95aac7b1c epoll: make epoll... |
1742 1743 |
slack = select_estimate_accuracy(&end_time); to = &expires; |
766b9f928 fs: poll/select/r... |
1744 |
*to = timespec64_to_ktime(end_time); |
95aac7b1c epoll: make epoll... |
1745 |
} else if (timeout == 0) { |
f4d93ad74 epoll: fix compil... |
1746 1747 |
/* * Avoid the unnecessary trip to the wait queue loop, if the |
c5a282e96 fs/epoll: reduce ... |
1748 1749 1750 1751 |
* caller specified a non blocking operation. We still need * lock because we could race and not see an epi being added * to the ready list while in irq callback. Thus incorrectly * returning 0 back to userspace. |
f4d93ad74 epoll: fix compil... |
1752 |
*/ |
95aac7b1c epoll: make epoll... |
1753 |
timed_out = 1; |
c5a282e96 fs/epoll: reduce ... |
1754 |
|
a218cc491 epoll: use rwlock... |
1755 |
write_lock_irq(&ep->lock); |
c5a282e96 fs/epoll: reduce ... |
1756 |
eavail = ep_events_available(ep); |
a218cc491 epoll: use rwlock... |
1757 |
write_unlock_irq(&ep->lock); |
c5a282e96 fs/epoll: reduce ... |
1758 |
|
35cff1a6e fs/epoll: rename ... |
1759 |
goto send_events; |
95aac7b1c epoll: make epoll... |
1760 |
} |
1da177e4c Linux-2.6.12-rc2 |
1761 |
|
f4d93ad74 epoll: fix compil... |
1762 |
fetch_events: |
bf3b9f637 epoll: Add busy p... |
1763 1764 1765 |
if (!ep_events_available(ep)) ep_busy_loop(ep, timed_out); |
c5a282e96 fs/epoll: reduce ... |
1766 1767 |
eavail = ep_events_available(ep); if (eavail) |
35cff1a6e fs/epoll: rename ... |
1768 |
goto send_events; |
1da177e4c Linux-2.6.12-rc2 |
1769 |
|
c5a282e96 fs/epoll: reduce ... |
1770 1771 1772 1773 1774 1775 |
/* * Busy poll timed out. Drop NAPI ID for now, we can add * it back in when we have moved a socket with a valid NAPI * ID onto the ready list. */ ep_reset_busy_poll_napi_id(ep); |
bf3b9f637 epoll: Add busy p... |
1776 |
|
412895f03 epoll: atomically... |
1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 |
do { /* * Internally init_wait() uses autoremove_wake_function(), * thus wait entry is removed from the wait queue on each * wakeup. Why it is important? In case of several waiters * each new wakeup will hit the next waiter, giving it the * chance to harvest new event. Otherwise wakeup can be * lost. This is also good performance-wise, because on * normal wakeup path no need to call __remove_wait_queue() * explicitly, thus ep->lock is not taken, which halts the * event delivery. */ init_wait(&wait); |
1da177e4c Linux-2.6.12-rc2 |
1790 |
|
65759097d epoll: call final... |
1791 |
write_lock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1792 |
/* |
65759097d epoll: call final... |
1793 1794 1795 |
* Barrierless variant, waitqueue_active() is called under * the same lock on wakeup ep_poll_callback() side, so it * is safe to avoid an explicit barrier. |
bf3b9f637 epoll: Add busy p... |
1796 |
*/ |
65759097d epoll: call final... |
1797 |
__set_current_state(TASK_INTERRUPTIBLE); |
bf3b9f637 epoll: Add busy p... |
1798 |
/* |
65759097d epoll: call final... |
1799 1800 1801 1802 1803 |
* Do the final check under the lock. ep_scan_ready_list() * plays with two lists (->rdllist and ->ovflist) and there * is always a race when both lists are empty for short * period of time although events are pending, so lock is * important. |
1da177e4c Linux-2.6.12-rc2 |
1804 |
*/ |
65759097d epoll: call final... |
1805 1806 1807 1808 1809 1810 |
eavail = ep_events_available(ep); if (!eavail) { if (signal_pending(current)) res = -EINTR; else __add_wait_queue_exclusive(&ep->wq, &wait); |
c5a282e96 fs/epoll: reduce ... |
1811 |
} |
65759097d epoll: call final... |
1812 |
write_unlock_irq(&ep->lock); |
95aac7b1c epoll: make epoll... |
1813 |
|
1afb979cd epoll: check for ... |
1814 |
if (!eavail && !res) |
19057a6a6 Merge 5.10.4 into... |
1815 1816 |
timed_out = !freezable_schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS); |
1da177e4c Linux-2.6.12-rc2 |
1817 |
|
1afb979cd epoll: check for ... |
1818 1819 1820 1821 1822 |
/* * We were woken up, thus go and try to harvest some events. * If timed out and still on the wait queue, recheck eavail * carefully under lock, below. */ |
412895f03 epoll: atomically... |
1823 |
eavail = 1; |
412895f03 epoll: atomically... |
1824 |
} while (0); |
1da177e4c Linux-2.6.12-rc2 |
1825 |
|
c5a282e96 fs/epoll: reduce ... |
1826 |
__set_current_state(TASK_RUNNING); |
1da177e4c Linux-2.6.12-rc2 |
1827 |
|
412895f03 epoll: atomically... |
1828 1829 |
if (!list_empty_careful(&wait.entry)) { write_lock_irq(&ep->lock); |
1afb979cd epoll: check for ... |
1830 1831 1832 1833 1834 1835 1836 1837 |
/* * If the thread timed out and is not on the wait queue, it * means that the thread was woken up after its timeout expired * before it could reacquire the lock. Thus, when wait.entry is * empty, it needs to harvest events. */ if (timed_out) eavail = list_empty(&wait.entry); |
412895f03 epoll: atomically... |
1838 1839 1840 |
__remove_wait_queue(&ep->wq, &wait); write_unlock_irq(&ep->lock); } |
35cff1a6e fs/epoll: rename ... |
1841 |
send_events: |
65759097d epoll: call final... |
1842 1843 1844 1845 1846 1847 1848 1849 1850 |
if (fatal_signal_pending(current)) { /* * Always short-circuit for fatal signals to allow * threads to make a timely exit without the chance of * finding more events available and fetching * repeatedly. */ res = -EINTR; } |
1da177e4c Linux-2.6.12-rc2 |
1851 1852 1853 1854 1855 1856 |
/* * Try to transfer events to user space. In case we get 0 events and * there's still timeout left over, we go trying again in search of * more luck. */ if (!res && eavail && |
95aac7b1c epoll: make epoll... |
1857 |
!(res = ep_send_events(ep, events, maxevents)) && !timed_out) |
f4d93ad74 epoll: fix compil... |
1858 |
goto fetch_events; |
1da177e4c Linux-2.6.12-rc2 |
1859 1860 1861 |
return res; } |
22bacca48 epoll: prevent cr... |
1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 |
/** * ep_loop_check_proc - Callback function to be passed to the @ep_call_nested() * API, to verify that adding an epoll file inside another * epoll structure, does not violate the constraints, in * terms of closed loops, or too deep chains (which can * result in excessive stack usage). * * @priv: Pointer to the epoll file to be currently checked. * @cookie: Original cookie for this call. This is the top-of-the-chain epoll * data structure pointer. * @call_nests: Current dept of the @ep_call_nested() call stack. * * Returns: Returns zero if adding the epoll @file inside current epoll * structure @ep does not violate the constraints, or -1 otherwise. */ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests) { int error = 0; struct file *file = priv; struct eventpoll *ep = file->private_data; |
28d82dc1c epoll: limit paths |
1882 |
struct eventpoll *ep_tovisit; |
22bacca48 epoll: prevent cr... |
1883 1884 |
struct rb_node *rbp; struct epitem *epi; |
d8805e633 epoll: fix spurio... |
1885 |
mutex_lock_nested(&ep->mtx, call_nests + 1); |
18306c404 epoll: replace ->... |
1886 |
ep->gen = loop_check_gen; |
b2ac2ea62 fs/epoll: use fas... |
1887 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
22bacca48 epoll: prevent cr... |
1888 1889 |
epi = rb_entry(rbp, struct epitem, rbn); if (unlikely(is_file_epoll(epi->ffd.file))) { |
28d82dc1c epoll: limit paths |
1890 |
ep_tovisit = epi->ffd.file->private_data; |
18306c404 epoll: replace ->... |
1891 |
if (ep_tovisit->gen == loop_check_gen) |
28d82dc1c epoll: limit paths |
1892 |
continue; |
74bdc1298 fs/epoll: remove ... |
1893 |
error = ep_call_nested(&poll_loop_ncalls, |
28d82dc1c epoll: limit paths |
1894 1895 |
ep_loop_check_proc, epi->ffd.file, ep_tovisit, current); |
22bacca48 epoll: prevent cr... |
1896 1897 |
if (error != 0) break; |
28d82dc1c epoll: limit paths |
1898 1899 1900 1901 1902 1903 1904 1905 1906 |
} else { /* * If we've reached a file that is not associated with * an ep, then we need to check if the newly added * links are going to add too many wakeup paths. We do * this by adding it to the tfile_check_list, if it's * not already there, and calling reverse_path_check() * during ep_insert(). */ |
a9ed4a656 epoll: Keep a ref... |
1907 |
if (list_empty(&epi->ffd.file->f_tfile_llink)) { |
77f4689de fix regression in... |
1908 1909 1910 |
if (get_file_rcu(epi->ffd.file)) list_add(&epi->ffd.file->f_tfile_llink, &tfile_check_list); |
a9ed4a656 epoll: Keep a ref... |
1911 |
} |
22bacca48 epoll: prevent cr... |
1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 |
} } mutex_unlock(&ep->mtx); return error; } /** * ep_loop_check - Performs a check to verify that adding an epoll file (@file) * another epoll file (represented by @ep) does not create * closed loops or too deep chains. * * @ep: Pointer to the epoll private data structure. * @file: Pointer to the epoll file to be checked. * * Returns: Returns zero if adding the epoll @file inside current epoll * structure @ep does not violate the constraints, or -1 otherwise. */ static int ep_loop_check(struct eventpoll *ep, struct file *file) { |
18306c404 epoll: replace ->... |
1932 |
return ep_call_nested(&poll_loop_ncalls, |
22bacca48 epoll: prevent cr... |
1933 |
ep_loop_check_proc, file, ep, current); |
28d82dc1c epoll: limit paths |
1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 |
} static void clear_tfile_check_list(void) { struct file *file; /* first clear the tfile_check_list */ while (!list_empty(&tfile_check_list)) { file = list_first_entry(&tfile_check_list, struct file, f_tfile_llink); list_del_init(&file->f_tfile_llink); |
a9ed4a656 epoll: Keep a ref... |
1945 |
fput(file); |
28d82dc1c epoll: limit paths |
1946 1947 |
} INIT_LIST_HEAD(&tfile_check_list); |
22bacca48 epoll: prevent cr... |
1948 |
} |
7699acd13 epoll cleanups: e... |
1949 |
/* |
523723bb5 fs/eventpoll.c: f... |
1950 |
* Open an eventpoll file descriptor. |
7699acd13 epoll cleanups: e... |
1951 |
*/ |
791eb22ee fs: add do_epoll_... |
1952 |
static int do_epoll_create(int flags) |
7699acd13 epoll cleanups: e... |
1953 |
{ |
28d82dc1c epoll: limit paths |
1954 |
int error, fd; |
bb57c3edc epoll: remove deb... |
1955 |
struct eventpoll *ep = NULL; |
28d82dc1c epoll: limit paths |
1956 |
struct file *file; |
7699acd13 epoll cleanups: e... |
1957 |
|
e38b36f32 flag parameters: ... |
1958 1959 |
/* Check the EPOLL_* constant for consistency. */ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC); |
296e236e9 epoll: fix epoll'... |
1960 1961 |
if (flags & ~EPOLL_CLOEXEC) return -EINVAL; |
7699acd13 epoll cleanups: e... |
1962 |
/* |
bb57c3edc epoll: remove deb... |
1963 |
* Create the internal data structure ("struct eventpoll"). |
7699acd13 epoll cleanups: e... |
1964 |
*/ |
9fe5ad9c8 flag parameters a... |
1965 |
error = ep_alloc(&ep); |
bb57c3edc epoll: remove deb... |
1966 1967 |
if (error < 0) return error; |
7699acd13 epoll cleanups: e... |
1968 1969 |
/* * Creates all the items needed to setup an eventpoll file. That is, |
2030a42ce [PATCH] sanitize ... |
1970 |
* a file structure and a free file descriptor. |
7699acd13 epoll cleanups: e... |
1971 |
*/ |
28d82dc1c epoll: limit paths |
1972 1973 1974 1975 1976 1977 |
fd = get_unused_fd_flags(O_RDWR | (flags & O_CLOEXEC)); if (fd < 0) { error = fd; goto out_free_ep; } file = anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep, |
628ff7c1d anonfd: Allow mak... |
1978 |
O_RDWR | (flags & O_CLOEXEC)); |
28d82dc1c epoll: limit paths |
1979 1980 1981 1982 |
if (IS_ERR(file)) { error = PTR_ERR(file); goto out_free_fd; } |
28d82dc1c epoll: limit paths |
1983 |
ep->file = file; |
98022748f eventpoll: use-af... |
1984 |
fd_install(fd, file); |
28d82dc1c epoll: limit paths |
1985 1986 1987 1988 1989 1990 |
return fd; out_free_fd: put_unused_fd(fd); out_free_ep: ep_free(ep); |
bb57c3edc epoll: remove deb... |
1991 |
return error; |
7699acd13 epoll cleanups: e... |
1992 |
} |
791eb22ee fs: add do_epoll_... |
1993 1994 1995 1996 |
SYSCALL_DEFINE1(epoll_create1, int, flags) { return do_epoll_create(flags); } |
5a8a82b1d [CVE-2009-0029] S... |
1997 |
SYSCALL_DEFINE1(epoll_create, int, size) |
a0998b50c flag parameters: ... |
1998 |
{ |
bfe3891a5 epoll: fix size c... |
1999 |
if (size <= 0) |
9fe5ad9c8 flag parameters a... |
2000 |
return -EINVAL; |
791eb22ee fs: add do_epoll_... |
2001 |
return do_epoll_create(0); |
a0998b50c flag parameters: ... |
2002 |
} |
39220e8d4 eventpoll: suppor... |
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 |
static inline int epoll_mutex_lock(struct mutex *mutex, int depth, bool nonblock) { if (!nonblock) { mutex_lock_nested(mutex, depth); return 0; } if (mutex_trylock(mutex)) return 0; return -EAGAIN; } int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, bool nonblock) |
7699acd13 epoll cleanups: e... |
2017 2018 |
{ int error; |
67347fe4e epoll: do not tak... |
2019 |
int full_check = 0; |
7e3fb5842 switch epoll_ctl(... |
2020 |
struct fd f, tf; |
7699acd13 epoll cleanups: e... |
2021 2022 |
struct eventpoll *ep; struct epitem *epi; |
67347fe4e epoll: do not tak... |
2023 |
struct eventpoll *tep = NULL; |
7699acd13 epoll cleanups: e... |
2024 |
|
7699acd13 epoll cleanups: e... |
2025 |
error = -EBADF; |
7e3fb5842 switch epoll_ctl(... |
2026 2027 |
f = fdget(epfd); if (!f.file) |
7699acd13 epoll cleanups: e... |
2028 2029 2030 |
goto error_return; /* Get the "struct file *" for the target file */ |
7e3fb5842 switch epoll_ctl(... |
2031 2032 |
tf = fdget(fd); if (!tf.file) |
7699acd13 epoll cleanups: e... |
2033 2034 2035 2036 |
goto error_fput; /* The target file descriptor must support poll */ error = -EPERM; |
9965ed174 fs: add new vfs_p... |
2037 |
if (!file_can_poll(tf.file)) |
7699acd13 epoll cleanups: e... |
2038 |
goto error_tgt_fput; |
4d7e30d98 epoll: Add a flag... |
2039 |
/* Check if EPOLLWAKEUP is allowed */ |
c680e41b3 eventpoll: fix un... |
2040 |
if (ep_op_has_event(op)) |
58e41a44c eventpoll: abstra... |
2041 |
ep_take_care_of_epollwakeup(epds); |
4d7e30d98 epoll: Add a flag... |
2042 |
|
7699acd13 epoll cleanups: e... |
2043 2044 2045 2046 2047 2048 |
/* * We have to check that the file structure underneath the file descriptor * the user passed to us _is_ an eventpoll file. And also we do not permit * adding an epoll file descriptor inside itself. */ error = -EINVAL; |
7e3fb5842 switch epoll_ctl(... |
2049 |
if (f.file == tf.file || !is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
2050 2051 2052 |
goto error_tgt_fput; /* |
df0108c5d epoll: add EPOLLE... |
2053 2054 2055 2056 |
* epoll adds to the wakeup queue at EPOLL_CTL_ADD time only, * so EPOLLEXCLUSIVE is not allowed for a EPOLL_CTL_MOD operation. * Also, we do not currently supported nested exclusive wakeups. */ |
58e41a44c eventpoll: abstra... |
2057 |
if (ep_op_has_event(op) && (epds->events & EPOLLEXCLUSIVE)) { |
b6a515c8a epoll: restrict E... |
2058 2059 2060 |
if (op == EPOLL_CTL_MOD) goto error_tgt_fput; if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) || |
58e41a44c eventpoll: abstra... |
2061 |
(epds->events & ~EPOLLEXCLUSIVE_OK_BITS))) |
b6a515c8a epoll: restrict E... |
2062 2063 |
goto error_tgt_fput; } |
df0108c5d epoll: add EPOLLE... |
2064 2065 |
/* |
7699acd13 epoll cleanups: e... |
2066 2067 2068 |
* At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
7e3fb5842 switch epoll_ctl(... |
2069 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2070 |
|
22bacca48 epoll: prevent cr... |
2071 2072 2073 |
/* * When we insert an epoll file descriptor, inside another epoll file * descriptor, there is the change of creating closed loops, which are |
28d82dc1c epoll: limit paths |
2074 2075 2076 2077 |
* better be handled here, than in more critical paths. While we are * checking for loops we also determine the list of files reachable * and hang them on the tfile_check_list, so we can check that we * haven't created too many possible wakeup paths. |
22bacca48 epoll: prevent cr... |
2078 |
* |
67347fe4e epoll: do not tak... |
2079 2080 2081 2082 2083 2084 |
* We do not need to take the global 'epumutex' on EPOLL_CTL_ADD when * the epoll file descriptor is attaching directly to a wakeup source, * unless the epoll file descriptor is nested. The purpose of taking the * 'epmutex' on add is to prevent complex toplogies such as loops and * deep wakeup paths from forming in parallel through multiple * EPOLL_CTL_ADD operations. |
22bacca48 epoll: prevent cr... |
2085 |
*/ |
39220e8d4 eventpoll: suppor... |
2086 2087 2088 |
error = epoll_mutex_lock(&ep->mtx, 0, nonblock); if (error) goto error_tgt_fput; |
28d82dc1c epoll: limit paths |
2089 |
if (op == EPOLL_CTL_ADD) { |
67347fe4e epoll: do not tak... |
2090 |
if (!list_empty(&f.file->f_ep_links) || |
fe0a916c1 epoll: EPOLL_CTL_... |
2091 |
ep->gen == loop_check_gen || |
67347fe4e epoll: do not tak... |
2092 |
is_file_epoll(tf.file)) { |
67347fe4e epoll: do not tak... |
2093 |
mutex_unlock(&ep->mtx); |
39220e8d4 eventpoll: suppor... |
2094 2095 2096 |
error = epoll_mutex_lock(&epmutex, 0, nonblock); if (error) goto error_tgt_fput; |
18306c404 epoll: replace ->... |
2097 |
loop_check_gen++; |
39220e8d4 eventpoll: suppor... |
2098 |
full_check = 1; |
67347fe4e epoll: do not tak... |
2099 2100 |
if (is_file_epoll(tf.file)) { error = -ELOOP; |
52c479697 do_epoll_ctl(): c... |
2101 |
if (ep_loop_check(ep, tf.file) != 0) |
67347fe4e epoll: do not tak... |
2102 |
goto error_tgt_fput; |
a9ed4a656 epoll: Keep a ref... |
2103 2104 |
} else { get_file(tf.file); |
67347fe4e epoll: do not tak... |
2105 2106 |
list_add(&tf.file->f_tfile_llink, &tfile_check_list); |
a9ed4a656 epoll: Keep a ref... |
2107 |
} |
39220e8d4 eventpoll: suppor... |
2108 |
error = epoll_mutex_lock(&ep->mtx, 0, nonblock); |
52c479697 do_epoll_ctl(): c... |
2109 |
if (error) |
39220e8d4 eventpoll: suppor... |
2110 |
goto error_tgt_fput; |
67347fe4e epoll: do not tak... |
2111 2112 |
if (is_file_epoll(tf.file)) { tep = tf.file->private_data; |
39220e8d4 eventpoll: suppor... |
2113 2114 2115 |
error = epoll_mutex_lock(&tep->mtx, 1, nonblock); if (error) { mutex_unlock(&ep->mtx); |
52c479697 do_epoll_ctl(): c... |
2116 |
goto error_tgt_fput; |
39220e8d4 eventpoll: suppor... |
2117 |
} |
13d518074 epoll: clear the ... |
2118 |
} |
67347fe4e epoll: do not tak... |
2119 2120 |
} } |
7699acd13 epoll cleanups: e... |
2121 |
|
67647d0fb epoll: fix some c... |
2122 2123 2124 2125 2126 |
/* * Try to lookup the file inside our RB tree, Since we grabbed "mtx" * above, we can be sure to be able to use the item looked up by * ep_find() till we release the mutex. */ |
7e3fb5842 switch epoll_ctl(... |
2127 |
epi = ep_find(ep, tf.file, fd); |
7699acd13 epoll cleanups: e... |
2128 2129 2130 2131 2132 |
error = -EINVAL; switch (op) { case EPOLL_CTL_ADD: if (!epi) { |
58e41a44c eventpoll: abstra... |
2133 2134 |
epds->events |= EPOLLERR | EPOLLHUP; error = ep_insert(ep, epds, tf.file, fd, full_check); |
7699acd13 epoll cleanups: e... |
2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 |
} else error = -EEXIST; break; case EPOLL_CTL_DEL: if (epi) error = ep_remove(ep, epi); else error = -ENOENT; break; case EPOLL_CTL_MOD: if (epi) { |
b6a515c8a epoll: restrict E... |
2146 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) { |
58e41a44c eventpoll: abstra... |
2147 2148 |
epds->events |= EPOLLERR | EPOLLHUP; error = ep_modify(ep, epi, epds); |
b6a515c8a epoll: restrict E... |
2149 |
} |
7699acd13 epoll cleanups: e... |
2150 2151 2152 2153 |
} else error = -ENOENT; break; } |
67347fe4e epoll: do not tak... |
2154 2155 |
if (tep != NULL) mutex_unlock(&tep->mtx); |
d47de16c7 fix epoll single ... |
2156 |
mutex_unlock(&ep->mtx); |
7699acd13 epoll cleanups: e... |
2157 2158 |
error_tgt_fput: |
52c479697 do_epoll_ctl(): c... |
2159 2160 |
if (full_check) { clear_tfile_check_list(); |
18306c404 epoll: replace ->... |
2161 |
loop_check_gen++; |
22bacca48 epoll: prevent cr... |
2162 |
mutex_unlock(&epmutex); |
52c479697 do_epoll_ctl(): c... |
2163 |
} |
22bacca48 epoll: prevent cr... |
2164 |
|
7e3fb5842 switch epoll_ctl(... |
2165 |
fdput(tf); |
7699acd13 epoll cleanups: e... |
2166 |
error_fput: |
7e3fb5842 switch epoll_ctl(... |
2167 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2168 |
error_return: |
7699acd13 epoll cleanups: e... |
2169 2170 2171 2172 2173 |
return error; } /* |
58e41a44c eventpoll: abstra... |
2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 |
* The following function implements the controller interface for * the eventpoll file that enables the insertion/removal/change of * file descriptors inside the interest set. */ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event __user *, event) { struct epoll_event epds; if (ep_op_has_event(op) && copy_from_user(&epds, event, sizeof(struct epoll_event))) return -EFAULT; |
39220e8d4 eventpoll: suppor... |
2186 |
return do_epoll_ctl(epfd, op, fd, &epds, false); |
58e41a44c eventpoll: abstra... |
2187 2188 2189 |
} /* |
7699acd13 epoll cleanups: e... |
2190 2191 2192 |
* Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_wait(2). */ |
791eb22ee fs: add do_epoll_... |
2193 2194 |
static int do_epoll_wait(int epfd, struct epoll_event __user *events, int maxevents, int timeout) |
7699acd13 epoll cleanups: e... |
2195 |
{ |
2903ff019 switch simple cas... |
2196 2197 |
int error; struct fd f; |
7699acd13 epoll cleanups: e... |
2198 |
struct eventpoll *ep; |
7699acd13 epoll cleanups: e... |
2199 2200 2201 2202 2203 |
/* The maximum number of event must be greater than zero */ if (maxevents <= 0 || maxevents > EP_MAX_EVENTS) return -EINVAL; /* Verify that the area passed by the user is writeable */ |
96d4f267e Remove 'type' arg... |
2204 |
if (!access_ok(events, maxevents * sizeof(struct epoll_event))) |
2903ff019 switch simple cas... |
2205 |
return -EFAULT; |
7699acd13 epoll cleanups: e... |
2206 2207 |
/* Get the "struct file *" for the eventpoll file */ |
2903ff019 switch simple cas... |
2208 2209 2210 |
f = fdget(epfd); if (!f.file) return -EBADF; |
7699acd13 epoll cleanups: e... |
2211 2212 2213 2214 2215 2216 |
/* * We have to check that the file structure underneath the fd * the user passed to us _is_ an eventpoll file. */ error = -EINVAL; |
2903ff019 switch simple cas... |
2217 |
if (!is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
2218 2219 2220 2221 2222 2223 |
goto error_fput; /* * At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
2903ff019 switch simple cas... |
2224 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2225 2226 2227 2228 2229 |
/* Time to fish for events ... */ error = ep_poll(ep, events, maxevents, timeout); error_fput: |
2903ff019 switch simple cas... |
2230 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2231 2232 |
return error; } |
791eb22ee fs: add do_epoll_... |
2233 2234 2235 2236 2237 |
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout) { return do_epoll_wait(epfd, events, maxevents, timeout); } |
7699acd13 epoll cleanups: e... |
2238 2239 2240 2241 |
/* * Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_pwait(2). */ |
5a8a82b1d [CVE-2009-0029] S... |
2242 2243 2244 |
SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout, const sigset_t __user *, sigmask, size_t, sigsetsize) |
7699acd13 epoll cleanups: e... |
2245 2246 |
{ int error; |
7699acd13 epoll cleanups: e... |
2247 2248 2249 2250 2251 |
/* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ |
b772434be signal: simplify ... |
2252 |
error = set_user_sigmask(sigmask, sigsetsize); |
ded653ccb signal: Add set_u... |
2253 2254 |
if (error) return error; |
7699acd13 epoll cleanups: e... |
2255 |
|
791eb22ee fs: add do_epoll_... |
2256 |
error = do_epoll_wait(epfd, events, maxevents, timeout); |
b772434be signal: simplify ... |
2257 |
restore_saved_sigmask_unless(error == -EINTR); |
7699acd13 epoll cleanups: e... |
2258 2259 2260 |
return error; } |
35280bd4a switch epoll_pwai... |
2261 2262 2263 2264 2265 2266 2267 2268 |
#ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout, const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) { long err; |
35280bd4a switch epoll_pwai... |
2269 2270 2271 2272 2273 |
/* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ |
b772434be signal: simplify ... |
2274 |
err = set_compat_user_sigmask(sigmask, sigsetsize); |
ded653ccb signal: Add set_u... |
2275 2276 |
if (err) return err; |
35280bd4a switch epoll_pwai... |
2277 |
|
791eb22ee fs: add do_epoll_... |
2278 |
err = do_epoll_wait(epfd, events, maxevents, timeout); |
b772434be signal: simplify ... |
2279 |
restore_saved_sigmask_unless(err == -EINTR); |
35280bd4a switch epoll_pwai... |
2280 2281 2282 2283 |
return err; } #endif |
1da177e4c Linux-2.6.12-rc2 |
2284 2285 |
static int __init eventpoll_init(void) { |
7ef9964e6 epoll: introduce ... |
2286 2287 2288 |
struct sysinfo si; si_meminfo(&si); |
9df04e1f2 epoll: drop max_u... |
2289 2290 2291 2292 |
/* * Allows top 4% of lomem to be allocated for epoll watches (per user). */ max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) / |
7ef9964e6 epoll: introduce ... |
2293 |
EP_ITEM_COST; |
52bd19f76 epoll: convert ma... |
2294 |
BUG_ON(max_user_watches < 0); |
1da177e4c Linux-2.6.12-rc2 |
2295 |
|
22bacca48 epoll: prevent cr... |
2296 2297 2298 2299 2300 |
/* * Initialize the structure used to perform epoll file descriptor * inclusion loops checks. */ ep_nested_calls_init(&poll_loop_ncalls); |
39732ca5a epoll: trim epite... |
2301 2302 2303 2304 2305 |
/* * We can have many thousands of epitems, so prevent this from * using an extra cache line on 64-bit (and smaller) CPUs */ BUILD_BUG_ON(sizeof(void *) <= 8 && sizeof(struct epitem) > 128); |
1da177e4c Linux-2.6.12-rc2 |
2306 2307 |
/* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), |
2ae928a94 epoll: account ep... |
2308 |
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2309 2310 2311 |
/* Allocates slab cache used to allocate "struct eppoll_entry" */ pwq_cache = kmem_cache_create("eventpoll_pwq", |
2ae928a94 epoll: account ep... |
2312 |
sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2313 |
|
1da177e4c Linux-2.6.12-rc2 |
2314 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
2315 |
} |
cea692418 epoll cleanups: e... |
2316 |
fs_initcall(eventpoll_init); |