Blame view
fs/eventpoll.c
59 KB
1da177e4c Linux-2.6.12-rc2 |
1 |
/* |
5071f97ec epoll: fix epoll'... |
2 3 |
* fs/eventpoll.c (Efficient event retrieval implementation) * Copyright (C) 2001,...,2009 Davide Libenzi |
1da177e4c Linux-2.6.12-rc2 |
4 5 6 7 8 9 10 11 12 |
* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * Davide Libenzi <davidel@xmailserver.org> * */ |
1da177e4c Linux-2.6.12-rc2 |
13 14 15 16 17 18 19 20 21 22 |
#include <linux/init.h> #include <linux/kernel.h> #include <linux/sched.h> #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 |
23 24 25 26 27 |
#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 |
28 29 30 31 32 |
#include <linux/rbtree.h> #include <linux/wait.h> #include <linux/eventpoll.h> #include <linux/mount.h> #include <linux/bitops.h> |
144efe3e3 [PATCH] sem2mutex... |
33 |
#include <linux/mutex.h> |
da66f7cb0 epoll: use anonym... |
34 |
#include <linux/anon_inodes.h> |
4d7e30d98 epoll: Add a flag... |
35 |
#include <linux/device.h> |
1da177e4c Linux-2.6.12-rc2 |
36 |
#include <asm/uaccess.h> |
1da177e4c Linux-2.6.12-rc2 |
37 38 |
#include <asm/io.h> #include <asm/mman.h> |
60063497a atomic: use <linu... |
39 |
#include <linux/atomic.h> |
138d22b58 fs, epoll: add pr... |
40 41 |
#include <linux/proc_fs.h> #include <linux/seq_file.h> |
35280bd4a switch epoll_pwai... |
42 |
#include <linux/compat.h> |
ae10b2b4e epoll: optimize E... |
43 |
#include <linux/rculist.h> |
1da177e4c Linux-2.6.12-rc2 |
44 |
|
1da177e4c Linux-2.6.12-rc2 |
45 46 47 48 |
/* * LOCKING: * There are three level of locking required by epoll : * |
144efe3e3 [PATCH] sem2mutex... |
49 |
* 1) epmutex (mutex) |
c7ea76302 epoll locks chang... |
50 51 |
* 2) ep->mtx (mutex) * 3) ep->lock (spinlock) |
1da177e4c Linux-2.6.12-rc2 |
52 53 54 55 56 57 58 59 60 |
* * The acquire order is the one listed above, from 1 to 3. * We need a spinlock (ep->lock) because we manipulate objects * 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 ... |
61 62 63 64 65 |
* 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 |
66 67 |
* 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... |
68 |
* close()d without a previous call to epoll_ctl(EPOLL_CTL_DEL). |
22bacca48 epoll: prevent cr... |
69 70 71 72 73 74 75 |
* 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... |
76 77 78 79 80 81 82 83 84 |
* 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 ... |
85 86 87 |
* It is possible to drop the "ep->mtx" and to use the global * mutex "epmutex" (together with "ep->lock") to have it working, * but having "ep->mtx" will make the interface more scalable. |
144efe3e3 [PATCH] sem2mutex... |
88 |
* Events that require holding "epmutex" are very rare, while for |
d47de16c7 fix epoll single ... |
89 90 |
* normal operations the epoll private "ep->mtx" will guarantee * a better scalability. |
1da177e4c Linux-2.6.12-rc2 |
91 |
*/ |
1da177e4c Linux-2.6.12-rc2 |
92 |
/* Epoll private bits inside the event mask */ |
4d7e30d98 epoll: Add a flag... |
93 |
#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET) |
1da177e4c Linux-2.6.12-rc2 |
94 |
|
5071f97ec epoll: fix epoll'... |
95 96 |
/* Maximum number of nesting allowed inside epoll sets */ #define EP_MAX_NESTS 4 |
1da177e4c Linux-2.6.12-rc2 |
97 |
|
b611967de [PATCH] epoll_pwa... |
98 |
#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event)) |
d47de16c7 fix epoll single ... |
99 |
#define EP_UNACTIVE_PTR ((void *) -1L) |
7ef9964e6 epoll: introduce ... |
100 |
#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry)) |
1da177e4c Linux-2.6.12-rc2 |
101 102 103 |
struct epoll_filefd { struct file *file; int fd; |
39732ca5a epoll: trim epite... |
104 |
} __packed; |
1da177e4c Linux-2.6.12-rc2 |
105 106 |
/* |
5071f97ec epoll: fix epoll'... |
107 108 |
* Structure used to track possible nested calls, for too deep recursions * and loop cycles. |
1da177e4c Linux-2.6.12-rc2 |
109 |
*/ |
5071f97ec epoll: fix epoll'... |
110 |
struct nested_call_node { |
1da177e4c Linux-2.6.12-rc2 |
111 |
struct list_head llink; |
5071f97ec epoll: fix epoll'... |
112 |
void *cookie; |
3fe4a975d epoll: fix nested... |
113 |
void *ctx; |
1da177e4c Linux-2.6.12-rc2 |
114 115 116 |
}; /* |
5071f97ec epoll: fix epoll'... |
117 118 |
* This structure is used as collector for nested calls, to check for * maximum recursion dept and loop cycles. |
1da177e4c Linux-2.6.12-rc2 |
119 |
*/ |
5071f97ec epoll: fix epoll'... |
120 121 |
struct nested_calls { struct list_head tasks_call_list; |
1da177e4c Linux-2.6.12-rc2 |
122 123 124 125 |
spinlock_t lock; }; /* |
d47de16c7 fix epoll single ... |
126 127 |
* 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... |
128 129 |
* 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 ... |
130 131 |
*/ struct epitem { |
ae10b2b4e epoll: optimize E... |
132 133 134 135 136 137 |
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 ... |
138 139 140 |
/* List header used to link this structure to the eventpoll ready list */ struct list_head rdllink; |
c7ea76302 epoll locks chang... |
141 142 143 144 145 |
/* * Works together "struct eventpoll"->ovflist in keeping the * single linked chain of items. */ struct epitem *next; |
d47de16c7 fix epoll single ... |
146 147 148 149 150 151 152 153 154 155 156 |
/* 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 ... |
157 158 |
/* List header used to link this item to the "struct file" items list */ struct list_head fllink; |
4d7e30d98 epoll: Add a flag... |
159 |
/* wakeup_source used when EPOLLWAKEUP is set */ |
eea1d5859 epoll: use RCU to... |
160 |
struct wakeup_source __rcu *ws; |
4d7e30d98 epoll: Add a flag... |
161 |
|
c7ea76302 epoll locks chang... |
162 163 |
/* The structure that describe the interested events and the source fd */ struct epoll_event event; |
d47de16c7 fix epoll single ... |
164 165 166 |
}; /* |
1da177e4c Linux-2.6.12-rc2 |
167 |
* This structure is stored inside the "private_data" member of the file |
bf6a41db7 fs/eventpoll.c: f... |
168 |
* structure and represents the main data structure for the eventpoll |
1da177e4c Linux-2.6.12-rc2 |
169 170 171 |
* interface. */ struct eventpoll { |
bf6a41db7 fs/eventpoll.c: f... |
172 |
/* Protect the access to this structure */ |
c7ea76302 epoll locks chang... |
173 |
spinlock_t lock; |
1da177e4c Linux-2.6.12-rc2 |
174 175 |
/* |
d47de16c7 fix epoll single ... |
176 177 178 179 |
* 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 |
180 |
*/ |
d47de16c7 fix epoll single ... |
181 |
struct mutex mtx; |
1da177e4c Linux-2.6.12-rc2 |
182 183 184 185 186 187 188 189 190 |
/* 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; |
67647d0fb epoll: fix some c... |
191 |
/* RB tree root used to store monitored fd structs */ |
1da177e4c Linux-2.6.12-rc2 |
192 |
struct rb_root 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 |
d47de16c7 fix epoll single ... |
197 198 199 |
* holding ->lock. */ 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 |
205 206 207 208 209 210 |
struct file *file; /* used to optimize loop detection check */ int visited; struct list_head visited_list_link; |
1da177e4c Linux-2.6.12-rc2 |
211 212 213 214 215 216 217 218 |
}; /* 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... |
219 |
struct epitem *base; |
1da177e4c Linux-2.6.12-rc2 |
220 221 222 223 224 225 226 227 228 229 |
/* * Wait queue item that will be linked to the target file wait * queue head. */ wait_queue_t wait; /* The wait queue head that linked the "wait" wait queue item */ wait_queue_head_t *whead; }; |
1da177e4c Linux-2.6.12-rc2 |
230 231 232 233 234 |
/* Wrapper struct used by poll queueing */ struct ep_pqueue { poll_table pt; struct epitem *epi; }; |
5071f97ec epoll: fix epoll'... |
235 236 237 238 239 |
/* Used by the ep_send_events() function as callback private data */ struct ep_send_events_data { int maxevents; struct epoll_event __user *events; }; |
1da177e4c Linux-2.6.12-rc2 |
240 |
/* |
7ef9964e6 epoll: introduce ... |
241 242 |
* Configuration options available inside /proc/sys/fs/epoll/ */ |
7ef9964e6 epoll: introduce ... |
243 |
/* Maximum number of epoll watched descriptors, per user */ |
52bd19f76 epoll: convert ma... |
244 |
static long max_user_watches __read_mostly; |
7ef9964e6 epoll: introduce ... |
245 246 |
/* |
d47de16c7 fix epoll single ... |
247 |
* This mutex is used to serialize ep_free() and eventpoll_release_file(). |
1da177e4c Linux-2.6.12-rc2 |
248 |
*/ |
7ef9964e6 epoll: introduce ... |
249 |
static DEFINE_MUTEX(epmutex); |
1da177e4c Linux-2.6.12-rc2 |
250 |
|
22bacca48 epoll: prevent cr... |
251 252 |
/* Used to check for epoll file descriptor inclusion loops */ static struct nested_calls poll_loop_ncalls; |
5071f97ec epoll: fix epoll'... |
253 254 255 256 257 |
/* Used for safe wake up implementation */ static struct nested_calls poll_safewake_ncalls; /* Used to call file's f_op->poll() under the nested calls boundaries */ static struct nested_calls poll_readywalk_ncalls; |
1da177e4c Linux-2.6.12-rc2 |
258 259 |
/* Slab cache used to allocate "struct epitem" */ |
e18b890bb [PATCH] slab: rem... |
260 |
static struct kmem_cache *epi_cache __read_mostly; |
1da177e4c Linux-2.6.12-rc2 |
261 262 |
/* Slab cache used to allocate "struct eppoll_entry" */ |
e18b890bb [PATCH] slab: rem... |
263 |
static struct kmem_cache *pwq_cache __read_mostly; |
1da177e4c Linux-2.6.12-rc2 |
264 |
|
28d82dc1c epoll: limit paths |
265 266 267 268 269 270 271 272 |
/* Visited nodes during ep_loop_check(), so we can unset them when we finish */ static LIST_HEAD(visited_list); /* * 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 ... |
273 274 275 |
#ifdef CONFIG_SYSCTL #include <linux/sysctl.h> |
52bd19f76 epoll: convert ma... |
276 277 |
static long zero; static long long_max = LONG_MAX; |
7ef9964e6 epoll: introduce ... |
278 |
|
1f7e0616c fs: convert use o... |
279 |
struct ctl_table epoll_table[] = { |
7ef9964e6 epoll: introduce ... |
280 |
{ |
7ef9964e6 epoll: introduce ... |
281 282 |
.procname = "max_user_watches", .data = &max_user_watches, |
52bd19f76 epoll: convert ma... |
283 |
.maxlen = sizeof(max_user_watches), |
7ef9964e6 epoll: introduce ... |
284 |
.mode = 0644, |
52bd19f76 epoll: convert ma... |
285 |
.proc_handler = proc_doulongvec_minmax, |
7ef9964e6 epoll: introduce ... |
286 |
.extra1 = &zero, |
52bd19f76 epoll: convert ma... |
287 |
.extra2 = &long_max, |
7ef9964e6 epoll: introduce ... |
288 |
}, |
ab09203e3 sysctl fs: Remove... |
289 |
{ } |
7ef9964e6 epoll: introduce ... |
290 291 |
}; #endif /* CONFIG_SYSCTL */ |
28d82dc1c epoll: limit paths |
292 293 294 295 296 297 |
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... |
298 |
|
67647d0fb epoll: fix some c... |
299 |
/* Setup the structure that is used as key for the RB tree */ |
b030a4dd6 [PATCH] Remove ev... |
300 301 302 303 304 305 |
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... |
306 |
/* Compare RB tree keys */ |
b030a4dd6 [PATCH] Remove ev... |
307 308 309 310 311 312 |
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... |
313 314 315 316 317 |
/* Tells us if the item is currently linked */ static inline int ep_is_linked(struct list_head *p) { return !list_empty(p); } |
971316f05 epoll: ep_unregis... |
318 319 320 321 |
static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_t *p) { return container_of(p, struct eppoll_entry, wait); } |
b030a4dd6 [PATCH] Remove ev... |
322 |
/* Get the "struct epitem" from a wait queue pointer */ |
cdac75e6f epoll: avoid kmem... |
323 |
static inline struct epitem *ep_item_from_wait(wait_queue_t *p) |
b030a4dd6 [PATCH] Remove ev... |
324 325 326 327 328 |
{ return container_of(p, struct eppoll_entry, wait)->base; } /* Get the "struct epitem" from an epoll queue wrapper */ |
cdac75e6f epoll: avoid kmem... |
329 |
static inline struct epitem *ep_item_from_epqueue(poll_table *p) |
b030a4dd6 [PATCH] Remove ev... |
330 331 332 333 334 |
{ return container_of(p, struct ep_pqueue, pt)->epi; } /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ |
6192bd536 epoll: optimizati... |
335 |
static inline int ep_op_has_event(int op) |
b030a4dd6 [PATCH] Remove ev... |
336 |
{ |
a80a6b85b revert "epoll: su... |
337 |
return op != EPOLL_CTL_DEL; |
b030a4dd6 [PATCH] Remove ev... |
338 |
} |
1da177e4c Linux-2.6.12-rc2 |
339 |
/* Initialize the poll safe wake up structure */ |
5071f97ec epoll: fix epoll'... |
340 |
static void ep_nested_calls_init(struct nested_calls *ncalls) |
1da177e4c Linux-2.6.12-rc2 |
341 |
{ |
5071f97ec epoll: fix epoll'... |
342 343 |
INIT_LIST_HEAD(&ncalls->tasks_call_list); spin_lock_init(&ncalls->lock); |
1da177e4c Linux-2.6.12-rc2 |
344 |
} |
5071f97ec epoll: fix epoll'... |
345 |
/** |
3fb0e584a epoll: move ready... |
346 347 348 349 350 351 352 353 354 355 356 357 358 |
* 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) { return !list_empty(&ep->rdllist) || ep->ovflist != EP_UNACTIVE_PTR; } /** |
5071f97ec epoll: fix epoll'... |
359 360 361 362 363 364 365 366 367 368 |
* 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. * @max_nests: Maximum number of allowed nesting calls. * @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... |
369 |
* @ctx: This instance context. |
5071f97ec epoll: fix epoll'... |
370 371 372 |
* * 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 |
373 |
*/ |
5071f97ec epoll: fix epoll'... |
374 375 |
static int ep_call_nested(struct nested_calls *ncalls, int max_nests, int (*nproc)(void *, void *, int), void *priv, |
3fe4a975d epoll: fix nested... |
376 |
void *cookie, void *ctx) |
1da177e4c Linux-2.6.12-rc2 |
377 |
{ |
5071f97ec epoll: fix epoll'... |
378 |
int error, call_nests = 0; |
1da177e4c Linux-2.6.12-rc2 |
379 |
unsigned long flags; |
5071f97ec epoll: fix epoll'... |
380 381 382 |
struct list_head *lsthead = &ncalls->tasks_call_list; struct nested_call_node *tncur; struct nested_call_node tnode; |
1da177e4c Linux-2.6.12-rc2 |
383 |
|
5071f97ec epoll: fix epoll'... |
384 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
385 |
|
5071f97ec epoll: fix epoll'... |
386 387 388 389 390 |
/* * 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... |
391 |
list_for_each_entry(tncur, lsthead, llink) { |
3fe4a975d epoll: fix nested... |
392 |
if (tncur->ctx == ctx && |
5071f97ec epoll: fix epoll'... |
393 |
(tncur->cookie == cookie || ++call_nests > max_nests)) { |
1da177e4c Linux-2.6.12-rc2 |
394 395 396 397 |
/* * Ops ... loop detected or maximum nest level reached. * We abort this wake by breaking the cycle itself. */ |
abff55cee epoll: don't use ... |
398 399 |
error = -1; goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
400 401 |
} } |
5071f97ec epoll: fix epoll'... |
402 |
/* Add the current task and cookie to the list */ |
3fe4a975d epoll: fix nested... |
403 |
tnode.ctx = ctx; |
5071f97ec epoll: fix epoll'... |
404 |
tnode.cookie = cookie; |
1da177e4c Linux-2.6.12-rc2 |
405 |
list_add(&tnode.llink, lsthead); |
5071f97ec epoll: fix epoll'... |
406 |
spin_unlock_irqrestore(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
407 |
|
5071f97ec epoll: fix epoll'... |
408 409 |
/* Call the nested function */ error = (*nproc)(priv, cookie, call_nests); |
1da177e4c Linux-2.6.12-rc2 |
410 411 |
/* Remove the current task from the list */ |
5071f97ec epoll: fix epoll'... |
412 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
413 |
list_del(&tnode.llink); |
3fe4a975d epoll: fix nested... |
414 |
out_unlock: |
5071f97ec epoll: fix epoll'... |
415 416 417 418 |
spin_unlock_irqrestore(&ncalls->lock, flags); return error; } |
02edc6fc4 epoll: comment th... |
419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 |
/* * 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... |
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 |
#ifdef CONFIG_DEBUG_LOCK_ALLOC static inline void ep_wake_up_nested(wait_queue_head_t *wqueue, unsigned long events, int subclass) { unsigned long flags; spin_lock_irqsave_nested(&wqueue->lock, flags, subclass); wake_up_locked_poll(wqueue, events); spin_unlock_irqrestore(&wqueue->lock, flags); } #else static inline void ep_wake_up_nested(wait_queue_head_t *wqueue, unsigned long events, int subclass) { wake_up_poll(wqueue, events); } #endif |
5071f97ec epoll: fix epoll'... |
461 462 |
static int ep_poll_wakeup_proc(void *priv, void *cookie, int call_nests) { |
2dfa4eeab epoll keyed wakeu... |
463 464 |
ep_wake_up_nested((wait_queue_head_t *) cookie, POLLIN, 1 + call_nests); |
5071f97ec epoll: fix epoll'... |
465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 |
return 0; } /* * Perform a safe wake up of the poll wait list. The problem is that * with the new callback'd wake up system, it is possible that the * poll callback is reentered from inside the call to wake_up() done * on the poll wait queue head. The rule is that we cannot reenter the * wake up code from the same task more than EP_MAX_NESTS times, * and we cannot reenter the same wait queue head at all. This will * enable to have a hierarchy of epoll file descriptor of no more than * EP_MAX_NESTS deep. */ static void ep_poll_safewake(wait_queue_head_t *wq) { |
3fe4a975d epoll: fix nested... |
480 |
int this_cpu = get_cpu(); |
5071f97ec epoll: fix epoll'... |
481 |
ep_call_nested(&poll_safewake_ncalls, EP_MAX_NESTS, |
3fe4a975d epoll: fix nested... |
482 483 484 |
ep_poll_wakeup_proc, NULL, wq, (void *) (long) this_cpu); put_cpu(); |
1da177e4c Linux-2.6.12-rc2 |
485 |
} |
971316f05 epoll: ep_unregis... |
486 487 488 489 490 491 492 493 494 495 496 |
static void ep_remove_wait_queue(struct eppoll_entry *pwq) { wait_queue_head_t *whead; rcu_read_lock(); /* If it is cleared by POLLFREE, it should be rcu-safe */ whead = rcu_dereference(pwq->whead); if (whead) remove_wait_queue(whead, &pwq->wait); rcu_read_unlock(); } |
1da177e4c Linux-2.6.12-rc2 |
497 |
/* |
d1bc90dd5 epoll: remove unn... |
498 499 500 |
* 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 |
501 |
*/ |
7699acd13 epoll cleanups: e... |
502 |
static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) |
1da177e4c Linux-2.6.12-rc2 |
503 |
{ |
7699acd13 epoll cleanups: e... |
504 505 |
struct list_head *lsthead = &epi->pwqlist; struct eppoll_entry *pwq; |
1da177e4c Linux-2.6.12-rc2 |
506 |
|
d1bc90dd5 epoll: remove unn... |
507 508 |
while (!list_empty(lsthead)) { pwq = list_first_entry(lsthead, struct eppoll_entry, llink); |
1da177e4c Linux-2.6.12-rc2 |
509 |
|
d1bc90dd5 epoll: remove unn... |
510 |
list_del(&pwq->llink); |
971316f05 epoll: ep_unregis... |
511 |
ep_remove_wait_queue(pwq); |
d1bc90dd5 epoll: remove unn... |
512 |
kmem_cache_free(pwq_cache, pwq); |
1da177e4c Linux-2.6.12-rc2 |
513 |
} |
1da177e4c Linux-2.6.12-rc2 |
514 |
} |
eea1d5859 epoll: use RCU to... |
515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 |
/* 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'... |
546 547 548 549 550 551 552 553 |
/** * 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... |
554 |
* @depth: The current depth of recursive f_op->poll calls. |
67347fe4e epoll: do not tak... |
555 |
* @ep_locked: caller already holds ep->mtx |
5071f97ec epoll: fix epoll'... |
556 557 558 559 560 561 |
* * Returns: The same integer error code returned by the @sproc callback. */ static int ep_scan_ready_list(struct eventpoll *ep, int (*sproc)(struct eventpoll *, struct list_head *, void *), |
67347fe4e epoll: do not tak... |
562 |
void *priv, int depth, bool ep_locked) |
5071f97ec epoll: fix epoll'... |
563 564 565 566 |
{ int error, pwake = 0; unsigned long flags; struct epitem *epi, *nepi; |
296e236e9 epoll: fix epoll'... |
567 |
LIST_HEAD(txlist); |
5071f97ec epoll: fix epoll'... |
568 569 570 |
/* * We need to lock this because we could be hit by |
e057e15ff epoll: clean up e... |
571 |
* eventpoll_release_file() and epoll_ctl(). |
5071f97ec epoll: fix epoll'... |
572 |
*/ |
67347fe4e epoll: do not tak... |
573 574 575 |
if (!ep_locked) mutex_lock_nested(&ep->mtx, depth); |
5071f97ec epoll: fix epoll'... |
576 577 578 579 580 581 582 583 584 585 |
/* * 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. */ spin_lock_irqsave(&ep->lock, flags); |
296e236e9 epoll: fix epoll'... |
586 |
list_splice_init(&ep->rdllist, &txlist); |
5071f97ec epoll: fix epoll'... |
587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 |
ep->ovflist = NULL; spin_unlock_irqrestore(&ep->lock, flags); /* * Now call the callback function. */ error = (*sproc)(ep, &txlist, priv); spin_lock_irqsave(&ep->lock, flags); /* * 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. */ for (nepi = ep->ovflist; (epi = nepi) != NULL; 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. */ |
4d7e30d98 epoll: Add a flag... |
609 |
if (!ep_is_linked(&epi->rdllink)) { |
5071f97ec epoll: fix epoll'... |
610 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
611 |
ep_pm_stay_awake(epi); |
4d7e30d98 epoll: Add a flag... |
612 |
} |
5071f97ec epoll: fix epoll'... |
613 614 615 616 617 618 619 620 621 622 623 624 |
} /* * 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. */ ep->ovflist = EP_UNACTIVE_PTR; /* * Quickly re-inject items left on "txlist". */ list_splice(&txlist, &ep->rdllist); |
4d7e30d98 epoll: Add a flag... |
625 |
__pm_relax(ep->ws); |
5071f97ec epoll: fix epoll'... |
626 627 628 |
if (!list_empty(&ep->rdllist)) { /* |
296e236e9 epoll: fix epoll'... |
629 630 |
* Wake up (if active) both the eventpoll wait list and * the ->poll() wait list (delayed after we release the lock). |
5071f97ec epoll: fix epoll'... |
631 632 633 634 635 636 637 |
*/ if (waitqueue_active(&ep->wq)) wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } spin_unlock_irqrestore(&ep->lock, flags); |
67347fe4e epoll: do not tak... |
638 639 |
if (!ep_locked) mutex_unlock(&ep->mtx); |
5071f97ec epoll: fix epoll'... |
640 641 642 643 644 645 646 |
/* We have to call this outside the lock */ if (pwake) ep_poll_safewake(&ep->poll_wait); return error; } |
ae10b2b4e epoll: optimize E... |
647 648 649 650 651 |
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 |
652 |
/* |
7699acd13 epoll cleanups: e... |
653 |
* Removes a "struct epitem" from the eventpoll RB tree and deallocates |
c7ea76302 epoll locks chang... |
654 |
* all the associated resources. Must be called with "mtx" held. |
7699acd13 epoll cleanups: e... |
655 656 657 |
*/ static int ep_remove(struct eventpoll *ep, struct epitem *epi) { |
7699acd13 epoll cleanups: e... |
658 659 |
unsigned long flags; struct file *file = epi->ffd.file; |
1da177e4c Linux-2.6.12-rc2 |
660 661 |
/* |
7699acd13 epoll cleanups: e... |
662 663 664 665 666 667 |
* Removes poll wait queue hooks. We _have_ to do this without holding * the "ep->lock" otherwise a deadlock might occur. This because of the * sequence of the lock acquisition. Here we do "ep->lock" then the wait * queue head lock when unregistering the wait queue. The wakeup callback * will run by holding the wait queue head lock and will call our callback * that will try to get "ep->lock". |
1da177e4c Linux-2.6.12-rc2 |
668 |
*/ |
7699acd13 epoll cleanups: e... |
669 |
ep_unregister_pollwait(ep, epi); |
1da177e4c Linux-2.6.12-rc2 |
670 |
|
7699acd13 epoll cleanups: e... |
671 |
/* Remove the current item from the list of epoll hooks */ |
684999149 Rename struct fil... |
672 |
spin_lock(&file->f_lock); |
ae10b2b4e epoll: optimize E... |
673 |
list_del_rcu(&epi->fllink); |
684999149 Rename struct fil... |
674 |
spin_unlock(&file->f_lock); |
1da177e4c Linux-2.6.12-rc2 |
675 |
|
cdac75e6f epoll: avoid kmem... |
676 |
rb_erase(&epi->rbn, &ep->rbr); |
1da177e4c Linux-2.6.12-rc2 |
677 |
|
c7ea76302 epoll locks chang... |
678 679 680 681 |
spin_lock_irqsave(&ep->lock, flags); if (ep_is_linked(&epi->rdllink)) list_del_init(&epi->rdllink); spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
682 |
|
eea1d5859 epoll: use RCU to... |
683 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
ae10b2b4e epoll: optimize E... |
684 685 686 687 688 689 690 691 |
/* * 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 |
692 |
|
52bd19f76 epoll: convert ma... |
693 |
atomic_long_dec(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
694 |
|
c7ea76302 epoll locks chang... |
695 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
696 |
} |
7699acd13 epoll cleanups: e... |
697 |
static void ep_free(struct eventpoll *ep) |
1da177e4c Linux-2.6.12-rc2 |
698 |
{ |
7699acd13 epoll cleanups: e... |
699 700 |
struct rb_node *rbp; struct epitem *epi; |
1da177e4c Linux-2.6.12-rc2 |
701 |
|
7699acd13 epoll cleanups: e... |
702 703 |
/* We need to release all tasks waiting for these file */ if (waitqueue_active(&ep->poll_wait)) |
5071f97ec epoll: fix epoll'... |
704 |
ep_poll_safewake(&ep->poll_wait); |
1da177e4c Linux-2.6.12-rc2 |
705 |
|
7699acd13 epoll cleanups: e... |
706 707 708 |
/* * 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 ... |
709 |
* We do not need to hold "ep->mtx" here because the epoll file |
7699acd13 epoll cleanups: e... |
710 711 |
* 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... |
712 |
* holding "epmutex" is sufficient here. |
7699acd13 epoll cleanups: e... |
713 714 |
*/ mutex_lock(&epmutex); |
1da177e4c Linux-2.6.12-rc2 |
715 716 |
/* |
7699acd13 epoll cleanups: e... |
717 |
* Walks through the whole tree by unregistering poll callbacks. |
1da177e4c Linux-2.6.12-rc2 |
718 |
*/ |
7699acd13 epoll cleanups: e... |
719 720 721 722 |
for (rbp = rb_first(&ep->rbr); rbp; rbp = rb_next(rbp)) { epi = rb_entry(rbp, struct epitem, rbn); ep_unregister_pollwait(ep, epi); |
91cf5ab60 epoll: add a resc... |
723 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
724 |
} |
1da177e4c Linux-2.6.12-rc2 |
725 726 |
/* |
7699acd13 epoll cleanups: e... |
727 728 |
* 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 ... |
729 |
* holding "epmutex" we can be sure that no file cleanup code will hit |
7699acd13 epoll cleanups: e... |
730 |
* us during this operation. So we can avoid the lock on "ep->lock". |
ddf676c38 epoll: lock ep->m... |
731 732 |
* We do not need to lock ep->mtx, either, we only do it to prevent * a lockdep warning. |
1da177e4c Linux-2.6.12-rc2 |
733 |
*/ |
ddf676c38 epoll: lock ep->m... |
734 |
mutex_lock(&ep->mtx); |
c80544dc0 sparse pointer us... |
735 |
while ((rbp = rb_first(&ep->rbr)) != NULL) { |
7699acd13 epoll cleanups: e... |
736 737 |
epi = rb_entry(rbp, struct epitem, rbn); ep_remove(ep, epi); |
91cf5ab60 epoll: add a resc... |
738 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
739 |
} |
ddf676c38 epoll: lock ep->m... |
740 |
mutex_unlock(&ep->mtx); |
1da177e4c Linux-2.6.12-rc2 |
741 |
|
7699acd13 epoll cleanups: e... |
742 |
mutex_unlock(&epmutex); |
d47de16c7 fix epoll single ... |
743 |
mutex_destroy(&ep->mtx); |
7ef9964e6 epoll: introduce ... |
744 |
free_uid(ep->user); |
4d7e30d98 epoll: Add a flag... |
745 |
wakeup_source_unregister(ep->ws); |
f0ee9aabb epoll: move kfree... |
746 |
kfree(ep); |
7699acd13 epoll cleanups: e... |
747 |
} |
1da177e4c Linux-2.6.12-rc2 |
748 |
|
7699acd13 epoll cleanups: e... |
749 750 751 |
static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep = file->private_data; |
1da177e4c Linux-2.6.12-rc2 |
752 |
|
f0ee9aabb epoll: move kfree... |
753 |
if (ep) |
7699acd13 epoll cleanups: e... |
754 |
ep_free(ep); |
7699acd13 epoll cleanups: e... |
755 |
|
7699acd13 epoll cleanups: e... |
756 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
757 |
} |
450d89ec0 epoll: cleanup: h... |
758 759 760 761 762 763 |
static inline unsigned int ep_item_poll(struct epitem *epi, poll_table *pt) { pt->_key = epi->event.events; return epi->ffd.file->f_op->poll(epi->ffd.file, pt) & epi->event.events; } |
296e236e9 epoll: fix epoll'... |
764 765 |
static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head, void *priv) |
5071f97ec epoll: fix epoll'... |
766 767 |
{ struct epitem *epi, *tmp; |
626cf2366 poll: add poll_re... |
768 |
poll_table pt; |
5071f97ec epoll: fix epoll'... |
769 |
|
626cf2366 poll: add poll_re... |
770 |
init_poll_funcptr(&pt, NULL); |
450d89ec0 epoll: cleanup: h... |
771 |
|
5071f97ec epoll: fix epoll'... |
772 |
list_for_each_entry_safe(epi, tmp, head, rdllink) { |
450d89ec0 epoll: cleanup: h... |
773 |
if (ep_item_poll(epi, &pt)) |
5071f97ec epoll: fix epoll'... |
774 |
return POLLIN | POLLRDNORM; |
296e236e9 epoll: fix epoll'... |
775 |
else { |
5071f97ec epoll: fix epoll'... |
776 777 778 779 780 |
/* * 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... |
781 |
__pm_relax(ep_wakeup_source(epi)); |
5071f97ec epoll: fix epoll'... |
782 |
list_del_init(&epi->rdllink); |
296e236e9 epoll: fix epoll'... |
783 |
} |
5071f97ec epoll: fix epoll'... |
784 785 786 787 |
} return 0; } |
67347fe4e epoll: do not tak... |
788 789 790 791 792 793 794 |
static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, poll_table *pt); struct readyevents_arg { struct eventpoll *ep; bool locked; }; |
5071f97ec epoll: fix epoll'... |
795 796 |
static int ep_poll_readyevents_proc(void *priv, void *cookie, int call_nests) { |
67347fe4e epoll: do not tak... |
797 798 799 800 |
struct readyevents_arg *arg = priv; return ep_scan_ready_list(arg->ep, ep_read_events_proc, NULL, call_nests + 1, arg->locked); |
5071f97ec epoll: fix epoll'... |
801 |
} |
7699acd13 epoll cleanups: e... |
802 803 |
static unsigned int ep_eventpoll_poll(struct file *file, poll_table *wait) { |
5071f97ec epoll: fix epoll'... |
804 |
int pollflags; |
7699acd13 epoll cleanups: e... |
805 |
struct eventpoll *ep = file->private_data; |
67347fe4e epoll: do not tak... |
806 807 808 809 810 811 812 813 |
struct readyevents_arg arg; /* * During ep_insert() we already hold the ep->mtx for the tfile. * Prevent re-aquisition. */ arg.locked = wait && (wait->_qproc == ep_ptable_queue_proc); arg.ep = ep; |
1da177e4c Linux-2.6.12-rc2 |
814 |
|
7699acd13 epoll cleanups: e... |
815 816 |
/* Insert inside our poll wait queue */ poll_wait(file, &ep->poll_wait, wait); |
5071f97ec epoll: fix epoll'... |
817 818 819 820 821 822 823 |
/* * Proceed to find out if wanted events are really available inside * the ready list. This need to be done under ep_call_nested() * supervision, since the call to f_op->poll() done on listed files * could re-enter here. */ pollflags = ep_call_nested(&poll_readywalk_ncalls, EP_MAX_NESTS, |
67347fe4e epoll: do not tak... |
824 |
ep_poll_readyevents_proc, &arg, ep, current); |
7699acd13 epoll cleanups: e... |
825 |
|
296e236e9 epoll: fix epoll'... |
826 |
return pollflags != -1 ? pollflags : 0; |
7699acd13 epoll cleanups: e... |
827 |
} |
138d22b58 fs, epoll: add pr... |
828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 |
#ifdef CONFIG_PROC_FS static int ep_show_fdinfo(struct seq_file *m, struct file *f) { struct eventpoll *ep = f->private_data; struct rb_node *rbp; int ret = 0; mutex_lock(&ep->mtx); for (rbp = rb_first(&ep->rbr); rbp; rbp = rb_next(rbp)) { struct epitem *epi = rb_entry(rbp, struct epitem, rbn); ret = seq_printf(m, "tfd: %8d events: %8x data: %16llx ", epi->ffd.fd, epi->event.events, (long long)epi->event.data); if (ret) break; } mutex_unlock(&ep->mtx); return ret; } #endif |
7699acd13 epoll cleanups: e... |
851 852 |
/* File callbacks that implement the eventpoll file behaviour */ static const struct file_operations eventpoll_fops = { |
138d22b58 fs, epoll: add pr... |
853 854 855 |
#ifdef CONFIG_PROC_FS .show_fdinfo = ep_show_fdinfo, #endif |
7699acd13 epoll cleanups: e... |
856 |
.release = ep_eventpoll_release, |
6038f373a llseek: automatic... |
857 858 |
.poll = ep_eventpoll_poll, .llseek = noop_llseek, |
7699acd13 epoll cleanups: e... |
859 |
}; |
b611967de [PATCH] epoll_pwa... |
860 |
/* |
7699acd13 epoll cleanups: e... |
861 862 863 |
* 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... |
864 |
*/ |
7699acd13 epoll cleanups: e... |
865 |
void eventpoll_release_file(struct file *file) |
b611967de [PATCH] epoll_pwa... |
866 |
{ |
7699acd13 epoll cleanups: e... |
867 |
struct eventpoll *ep; |
ebe06187b epoll: fix use-af... |
868 |
struct epitem *epi, *next; |
b611967de [PATCH] epoll_pwa... |
869 870 |
/* |
684999149 Rename struct fil... |
871 |
* We don't want to get "file->f_lock" because it is not |
7699acd13 epoll cleanups: e... |
872 |
* necessary. It is not necessary because we're in the "struct file" |
25985edce Fix common misspe... |
873 |
* cleanup path, and this means that no one is using this file anymore. |
5071f97ec epoll: fix epoll'... |
874 |
* So, for example, epoll_ctl() cannot hit here since if we reach this |
67647d0fb epoll: fix some c... |
875 |
* point, the file counter already went to zero and fget() would fail. |
d47de16c7 fix epoll single ... |
876 |
* The only hit might come from ep_free() but by holding the mutex |
7699acd13 epoll cleanups: e... |
877 |
* will correctly serialize the operation. We do need to acquire |
d47de16c7 fix epoll single ... |
878 |
* "ep->mtx" after "epmutex" because ep_remove() requires it when called |
7699acd13 epoll cleanups: e... |
879 |
* from anywhere but ep_free(). |
684999149 Rename struct fil... |
880 881 |
* * Besides, ep_remove() acquires the lock, so we can't hold it here. |
b611967de [PATCH] epoll_pwa... |
882 |
*/ |
7699acd13 epoll cleanups: e... |
883 |
mutex_lock(&epmutex); |
ebe06187b epoll: fix use-af... |
884 |
list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) { |
7699acd13 epoll cleanups: e... |
885 |
ep = epi->ep; |
d8805e633 epoll: fix spurio... |
886 |
mutex_lock_nested(&ep->mtx, 0); |
7699acd13 epoll cleanups: e... |
887 |
ep_remove(ep, epi); |
d47de16c7 fix epoll single ... |
888 |
mutex_unlock(&ep->mtx); |
b611967de [PATCH] epoll_pwa... |
889 |
} |
7699acd13 epoll cleanups: e... |
890 |
mutex_unlock(&epmutex); |
b611967de [PATCH] epoll_pwa... |
891 |
} |
53d2be79d [PATCH] epoll: fi... |
892 |
static int ep_alloc(struct eventpoll **pep) |
1da177e4c Linux-2.6.12-rc2 |
893 |
{ |
7ef9964e6 epoll: introduce ... |
894 895 896 |
int error; struct user_struct *user; struct eventpoll *ep; |
1da177e4c Linux-2.6.12-rc2 |
897 |
|
7ef9964e6 epoll: introduce ... |
898 |
user = get_current_user(); |
7ef9964e6 epoll: introduce ... |
899 900 901 902 |
error = -ENOMEM; ep = kzalloc(sizeof(*ep), GFP_KERNEL); if (unlikely(!ep)) goto free_uid; |
1da177e4c Linux-2.6.12-rc2 |
903 |
|
c7ea76302 epoll locks chang... |
904 |
spin_lock_init(&ep->lock); |
d47de16c7 fix epoll single ... |
905 |
mutex_init(&ep->mtx); |
1da177e4c Linux-2.6.12-rc2 |
906 907 908 909 |
init_waitqueue_head(&ep->wq); init_waitqueue_head(&ep->poll_wait); INIT_LIST_HEAD(&ep->rdllist); ep->rbr = RB_ROOT; |
d47de16c7 fix epoll single ... |
910 |
ep->ovflist = EP_UNACTIVE_PTR; |
7ef9964e6 epoll: introduce ... |
911 |
ep->user = user; |
1da177e4c Linux-2.6.12-rc2 |
912 |
|
53d2be79d [PATCH] epoll: fi... |
913 |
*pep = ep; |
1da177e4c Linux-2.6.12-rc2 |
914 |
|
1da177e4c Linux-2.6.12-rc2 |
915 |
return 0; |
7ef9964e6 epoll: introduce ... |
916 917 918 919 |
free_uid: free_uid(user); return error; |
1da177e4c Linux-2.6.12-rc2 |
920 |
} |
1da177e4c Linux-2.6.12-rc2 |
921 |
/* |
c7ea76302 epoll locks chang... |
922 923 924 |
* 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 |
925 926 927 928 |
*/ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) { int kcmp; |
1da177e4c Linux-2.6.12-rc2 |
929 930 931 |
struct rb_node *rbp; struct epitem *epi, *epir = NULL; struct epoll_filefd ffd; |
b030a4dd6 [PATCH] Remove ev... |
932 |
ep_set_ffd(&ffd, file, fd); |
1da177e4c Linux-2.6.12-rc2 |
933 934 |
for (rbp = ep->rbr.rb_node; rbp; ) { epi = rb_entry(rbp, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
935 |
kcmp = ep_cmp_ffd(&ffd, &epi->ffd); |
1da177e4c Linux-2.6.12-rc2 |
936 937 938 939 940 |
if (kcmp > 0) rbp = rbp->rb_right; else if (kcmp < 0) rbp = rbp->rb_left; else { |
1da177e4c Linux-2.6.12-rc2 |
941 942 943 944 |
epir = epi; break; } } |
1da177e4c Linux-2.6.12-rc2 |
945 |
|
1da177e4c Linux-2.6.12-rc2 |
946 947 |
return epir; } |
1da177e4c Linux-2.6.12-rc2 |
948 |
/* |
7699acd13 epoll cleanups: e... |
949 |
* This is the callback that is passed to the wait queue wakeup |
bf6a41db7 fs/eventpoll.c: f... |
950 |
* mechanism. It is called by the stored file descriptors when they |
7699acd13 epoll cleanups: e... |
951 |
* have events to report. |
1da177e4c Linux-2.6.12-rc2 |
952 |
*/ |
7699acd13 epoll cleanups: e... |
953 |
static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *key) |
1da177e4c Linux-2.6.12-rc2 |
954 |
{ |
7699acd13 epoll cleanups: e... |
955 956 957 958 |
int pwake = 0; unsigned long flags; struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; |
1da177e4c Linux-2.6.12-rc2 |
959 |
|
971316f05 epoll: ep_unregis... |
960 961 962 963 964 965 966 967 |
if ((unsigned long)key & POLLFREE) { ep_pwq_from_wait(wait)->whead = NULL; /* * whead = NULL above can race with ep_remove_wait_queue() * which can do another remove_wait_queue() after us, so we * can't use __remove_wait_queue(). whead->lock is held by * the caller. */ |
d80e731ec epoll: introduce ... |
968 |
list_del_init(&wait->task_list); |
971316f05 epoll: ep_unregis... |
969 |
} |
d80e731ec epoll: introduce ... |
970 |
|
c7ea76302 epoll locks chang... |
971 |
spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
972 |
|
7699acd13 epoll cleanups: e... |
973 974 975 976 977 978 979 |
/* * 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 ... |
980 981 982 |
goto out_unlock; /* |
2dfa4eeab epoll keyed wakeu... |
983 984 985 986 987 988 989 990 991 |
* 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. */ if (key && !((unsigned long) key & epi->event.events)) goto out_unlock; /* |
bf6a41db7 fs/eventpoll.c: f... |
992 |
* If we are transferring events to userspace, we can hold no locks |
d47de16c7 fix epoll single ... |
993 |
* (because we're accessing user memory, and because of linux f_op->poll() |
bf6a41db7 fs/eventpoll.c: f... |
994 |
* semantics). All the events that happen during that period of time are |
d47de16c7 fix epoll single ... |
995 996 997 998 999 1000 |
* chained in ep->ovflist and requeued later on. */ if (unlikely(ep->ovflist != EP_UNACTIVE_PTR)) { if (epi->next == EP_UNACTIVE_PTR) { epi->next = ep->ovflist; ep->ovflist = epi; |
4d7e30d98 epoll: Add a flag... |
1001 1002 1003 1004 1005 1006 1007 |
if (epi->ws) { /* * Activate ep->ws since epi->ws may get * deactivated at any time. */ __pm_stay_awake(ep->ws); } |
d47de16c7 fix epoll single ... |
1008 1009 1010 |
} goto out_unlock; } |
1da177e4c Linux-2.6.12-rc2 |
1011 |
|
7699acd13 epoll cleanups: e... |
1012 |
/* If this file is already in the ready list we exit soon */ |
4d7e30d98 epoll: Add a flag... |
1013 |
if (!ep_is_linked(&epi->rdllink)) { |
5071f97ec epoll: fix epoll'... |
1014 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1015 |
ep_pm_stay_awake_rcu(epi); |
4d7e30d98 epoll: Add a flag... |
1016 |
} |
7699acd13 epoll cleanups: e... |
1017 |
|
7699acd13 epoll cleanups: e... |
1018 1019 1020 1021 1022 |
/* * Wake up ( if active ) both the eventpoll wait list and the ->poll() * wait list. */ if (waitqueue_active(&ep->wq)) |
4a6e9e2ce Use wake_up_locke... |
1023 |
wake_up_locked(&ep->wq); |
7699acd13 epoll cleanups: e... |
1024 1025 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
d47de16c7 fix epoll single ... |
1026 |
out_unlock: |
c7ea76302 epoll locks chang... |
1027 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1028 |
|
7699acd13 epoll cleanups: e... |
1029 1030 |
/* We have to call this outside the lock */ if (pwake) |
5071f97ec epoll: fix epoll'... |
1031 |
ep_poll_safewake(&ep->poll_wait); |
7699acd13 epoll cleanups: e... |
1032 1033 1034 |
return 1; } |
1da177e4c Linux-2.6.12-rc2 |
1035 1036 1037 1038 1039 1040 1041 1042 |
/* * 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... |
1043 |
struct epitem *epi = ep_item_from_epqueue(pt); |
1da177e4c Linux-2.6.12-rc2 |
1044 |
struct eppoll_entry *pwq; |
e94b17660 [PATCH] slab: rem... |
1045 |
if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL))) { |
1da177e4c Linux-2.6.12-rc2 |
1046 1047 1048 1049 1050 1051 |
init_waitqueue_func_entry(&pwq->wait, ep_poll_callback); pwq->whead = whead; pwq->base = epi; add_wait_queue(whead, &pwq->wait); list_add_tail(&pwq->llink, &epi->pwqlist); epi->nwait++; |
296e236e9 epoll: fix epoll'... |
1052 |
} else { |
1da177e4c Linux-2.6.12-rc2 |
1053 1054 |
/* We have to signal that an error occurred */ epi->nwait = -1; |
296e236e9 epoll: fix epoll'... |
1055 |
} |
1da177e4c Linux-2.6.12-rc2 |
1056 |
} |
1da177e4c Linux-2.6.12-rc2 |
1057 1058 1059 1060 1061 1062 1063 1064 1065 |
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) { int kcmp; struct rb_node **p = &ep->rbr.rb_node, *parent = NULL; struct epitem *epic; while (*p) { parent = *p; epic = rb_entry(parent, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
1066 |
kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd); |
1da177e4c Linux-2.6.12-rc2 |
1067 1068 1069 1070 1071 1072 1073 1074 |
if (kcmp > 0) p = &parent->rb_right; else p = &parent->rb_left; } rb_link_node(&epi->rbn, parent, p); rb_insert_color(&epi->rbn, &ep->rbr); } |
a80a6b85b revert "epoll: su... |
1075 |
|
28d82dc1c epoll: limit paths |
1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 |
#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... |
1093 1094 1095 |
/* Allow an arbitrary number of depth 1 paths */ if (nests == 0) return 0; |
28d82dc1c epoll: limit paths |
1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 |
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... |
1115 1116 1117 |
/* 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 |
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 |
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, EP_MAX_NESTS, 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... |
1140 |
rcu_read_unlock(); |
28d82dc1c epoll: limit paths |
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 |
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 |
1156 1157 1158 1159 1160 |
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 |
1161 1162 1163 1164 1165 1166 1167 1168 1169 |
path_count_init(); error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, reverse_path_check_proc, current_file, current_file, current); if (error) break; } return error; } |
4d7e30d98 epoll: Add a flag... |
1170 1171 1172 |
static int ep_create_wakeup_source(struct epitem *epi) { const char *name; |
eea1d5859 epoll: use RCU to... |
1173 |
struct wakeup_source *ws; |
4d7e30d98 epoll: Add a flag... |
1174 1175 1176 1177 1178 1179 1180 1181 |
if (!epi->ep->ws) { epi->ep->ws = wakeup_source_register("eventpoll"); if (!epi->ep->ws) return -ENOMEM; } name = epi->ffd.file->f_path.dentry->d_name.name; |
eea1d5859 epoll: use RCU to... |
1182 1183 1184 |
ws = wakeup_source_register(name); if (!ws) |
4d7e30d98 epoll: Add a flag... |
1185 |
return -ENOMEM; |
eea1d5859 epoll: use RCU to... |
1186 |
rcu_assign_pointer(epi->ws, ws); |
4d7e30d98 epoll: Add a flag... |
1187 1188 1189 |
return 0; } |
eea1d5859 epoll: use RCU to... |
1190 1191 |
/* 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... |
1192 |
{ |
eea1d5859 epoll: use RCU to... |
1193 |
struct wakeup_source *ws = ep_wakeup_source(epi); |
d6d67e723 epoll: cleanup: u... |
1194 |
RCU_INIT_POINTER(epi->ws, NULL); |
eea1d5859 epoll: use RCU to... |
1195 1196 1197 1198 1199 1200 1201 1202 |
/* * 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... |
1203 |
} |
c7ea76302 epoll locks chang... |
1204 1205 1206 |
/* * Must be called with "mtx" held. */ |
1da177e4c Linux-2.6.12-rc2 |
1207 |
static int ep_insert(struct eventpoll *ep, struct epoll_event *event, |
67347fe4e epoll: do not tak... |
1208 |
struct file *tfile, int fd, int full_check) |
1da177e4c Linux-2.6.12-rc2 |
1209 1210 1211 |
{ int error, revents, pwake = 0; unsigned long flags; |
52bd19f76 epoll: convert ma... |
1212 |
long user_watches; |
1da177e4c Linux-2.6.12-rc2 |
1213 1214 |
struct epitem *epi; struct ep_pqueue epq; |
52bd19f76 epoll: convert ma... |
1215 1216 |
user_watches = atomic_long_read(&ep->user->epoll_watches); if (unlikely(user_watches >= max_user_watches)) |
7ef9964e6 epoll: introduce ... |
1217 |
return -ENOSPC; |
e94b17660 [PATCH] slab: rem... |
1218 |
if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) |
7ef9964e6 epoll: introduce ... |
1219 |
return -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1220 1221 |
/* Item initialization follow here ... */ |
1da177e4c Linux-2.6.12-rc2 |
1222 1223 |
INIT_LIST_HEAD(&epi->rdllink); INIT_LIST_HEAD(&epi->fllink); |
1da177e4c Linux-2.6.12-rc2 |
1224 1225 |
INIT_LIST_HEAD(&epi->pwqlist); epi->ep = ep; |
b030a4dd6 [PATCH] Remove ev... |
1226 |
ep_set_ffd(&epi->ffd, tfile, fd); |
1da177e4c Linux-2.6.12-rc2 |
1227 |
epi->event = *event; |
1da177e4c Linux-2.6.12-rc2 |
1228 |
epi->nwait = 0; |
d47de16c7 fix epoll single ... |
1229 |
epi->next = EP_UNACTIVE_PTR; |
4d7e30d98 epoll: Add a flag... |
1230 1231 1232 1233 1234 |
if (epi->event.events & EPOLLWAKEUP) { error = ep_create_wakeup_source(epi); if (error) goto error_create_wakeup_source; } else { |
eea1d5859 epoll: use RCU to... |
1235 |
RCU_INIT_POINTER(epi->ws, NULL); |
4d7e30d98 epoll: Add a flag... |
1236 |
} |
1da177e4c Linux-2.6.12-rc2 |
1237 1238 1239 1240 1241 1242 1243 1244 |
/* 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... |
1245 1246 1247 |
* 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 |
1248 |
*/ |
450d89ec0 epoll: cleanup: h... |
1249 |
revents = ep_item_poll(epi, &epq.pt); |
1da177e4c Linux-2.6.12-rc2 |
1250 1251 1252 1253 1254 1255 |
/* * 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 ... |
1256 |
error = -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1257 |
if (epi->nwait < 0) |
7699acd13 epoll cleanups: e... |
1258 |
goto error_unregister; |
1da177e4c Linux-2.6.12-rc2 |
1259 1260 |
/* Add the current item to the list of active epoll hook for this file */ |
684999149 Rename struct fil... |
1261 |
spin_lock(&tfile->f_lock); |
ae10b2b4e epoll: optimize E... |
1262 |
list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); |
684999149 Rename struct fil... |
1263 |
spin_unlock(&tfile->f_lock); |
1da177e4c Linux-2.6.12-rc2 |
1264 |
|
c7ea76302 epoll locks chang... |
1265 1266 1267 1268 |
/* * Add the current item to the RB tree. All RB tree operations are * protected by "mtx", and ep_insert() is called with "mtx" held. */ |
1da177e4c Linux-2.6.12-rc2 |
1269 |
ep_rbtree_insert(ep, epi); |
28d82dc1c epoll: limit paths |
1270 1271 |
/* now check if we've created too many backpaths */ error = -EINVAL; |
67347fe4e epoll: do not tak... |
1272 |
if (full_check && reverse_path_check()) |
28d82dc1c epoll: limit paths |
1273 |
goto error_remove_epi; |
c7ea76302 epoll locks chang... |
1274 1275 |
/* We have to drop the new item inside our item list to keep track of it */ spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1276 |
/* If the file is already "ready" we drop it inside the ready list */ |
b030a4dd6 [PATCH] Remove ev... |
1277 |
if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) { |
1da177e4c Linux-2.6.12-rc2 |
1278 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1279 |
ep_pm_stay_awake(epi); |
1da177e4c Linux-2.6.12-rc2 |
1280 1281 1282 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
4a6e9e2ce Use wake_up_locke... |
1283 |
wake_up_locked(&ep->wq); |
1da177e4c Linux-2.6.12-rc2 |
1284 1285 1286 |
if (waitqueue_active(&ep->poll_wait)) pwake++; } |
c7ea76302 epoll locks chang... |
1287 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1288 |
|
52bd19f76 epoll: convert ma... |
1289 |
atomic_long_inc(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
1290 |
|
1da177e4c Linux-2.6.12-rc2 |
1291 1292 |
/* We have to call this outside the lock */ if (pwake) |
5071f97ec epoll: fix epoll'... |
1293 |
ep_poll_safewake(&ep->poll_wait); |
1da177e4c Linux-2.6.12-rc2 |
1294 |
|
1da177e4c Linux-2.6.12-rc2 |
1295 |
return 0; |
28d82dc1c epoll: limit paths |
1296 1297 |
error_remove_epi: spin_lock(&tfile->f_lock); |
ae10b2b4e epoll: optimize E... |
1298 |
list_del_rcu(&epi->fllink); |
28d82dc1c epoll: limit paths |
1299 1300 1301 |
spin_unlock(&tfile->f_lock); rb_erase(&epi->rbn, &ep->rbr); |
7699acd13 epoll cleanups: e... |
1302 |
error_unregister: |
1da177e4c Linux-2.6.12-rc2 |
1303 1304 1305 1306 |
ep_unregister_pollwait(ep, epi); /* * We need to do this because an event could have been arrived on some |
67647d0fb epoll: fix some c... |
1307 1308 1309 |
* 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 |
1310 |
*/ |
c7ea76302 epoll locks chang... |
1311 |
spin_lock_irqsave(&ep->lock, flags); |
b030a4dd6 [PATCH] Remove ev... |
1312 |
if (ep_is_linked(&epi->rdllink)) |
6192bd536 epoll: optimizati... |
1313 |
list_del_init(&epi->rdllink); |
c7ea76302 epoll locks chang... |
1314 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1315 |
|
eea1d5859 epoll: use RCU to... |
1316 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
4d7e30d98 epoll: Add a flag... |
1317 1318 |
error_create_wakeup_source: |
b030a4dd6 [PATCH] Remove ev... |
1319 |
kmem_cache_free(epi_cache, epi); |
7ef9964e6 epoll: introduce ... |
1320 |
|
1da177e4c Linux-2.6.12-rc2 |
1321 1322 |
return error; } |
1da177e4c Linux-2.6.12-rc2 |
1323 1324 |
/* * Modify the interest event mask by dropping an event if the new mask |
c7ea76302 epoll locks chang... |
1325 |
* has a match in the current file status. Must be called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1326 1327 1328 1329 1330 |
*/ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_event *event) { int pwake = 0; unsigned int revents; |
626cf2366 poll: add poll_re... |
1331 1332 1333 |
poll_table pt; init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1334 1335 |
/* |
e057e15ff epoll: clean up e... |
1336 1337 1338 |
* 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 |
1339 |
*/ |
128dd1759 epoll: prevent mi... |
1340 |
epi->event.events = event->events; /* need barrier below */ |
e057e15ff epoll: clean up e... |
1341 |
epi->event.data = event->data; /* protected by mtx */ |
4d7e30d98 epoll: Add a flag... |
1342 |
if (epi->event.events & EPOLLWAKEUP) { |
eea1d5859 epoll: use RCU to... |
1343 |
if (!ep_has_wakeup_source(epi)) |
4d7e30d98 epoll: Add a flag... |
1344 |
ep_create_wakeup_source(epi); |
eea1d5859 epoll: use RCU to... |
1345 |
} else if (ep_has_wakeup_source(epi)) { |
4d7e30d98 epoll: Add a flag... |
1346 1347 |
ep_destroy_wakeup_source(epi); } |
1da177e4c Linux-2.6.12-rc2 |
1348 1349 |
/* |
128dd1759 epoll: prevent mi... |
1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 |
* 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(). * We need this because we did not take ep->lock while * changing epi above (but ep_poll_callback does take * ep->lock). * * 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 |
1370 1371 1372 |
* Get current event bits. We can safely use the file* here because * its usage count has been increased by the caller of this function. */ |
450d89ec0 epoll: cleanup: h... |
1373 |
revents = ep_item_poll(epi, &pt); |
1da177e4c Linux-2.6.12-rc2 |
1374 |
|
1da177e4c Linux-2.6.12-rc2 |
1375 |
/* |
c7ea76302 epoll locks chang... |
1376 |
* If the item is "hot" and it is not registered inside the ready |
67647d0fb epoll: fix some c... |
1377 |
* list, push it inside. |
1da177e4c Linux-2.6.12-rc2 |
1378 |
*/ |
c7ea76302 epoll locks chang... |
1379 |
if (revents & event->events) { |
e057e15ff epoll: clean up e... |
1380 |
spin_lock_irq(&ep->lock); |
c7ea76302 epoll locks chang... |
1381 1382 |
if (!ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1383 |
ep_pm_stay_awake(epi); |
c7ea76302 epoll locks chang... |
1384 1385 1386 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
4a6e9e2ce Use wake_up_locke... |
1387 |
wake_up_locked(&ep->wq); |
c7ea76302 epoll locks chang... |
1388 1389 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
7699acd13 epoll cleanups: e... |
1390 |
} |
e057e15ff epoll: clean up e... |
1391 |
spin_unlock_irq(&ep->lock); |
7699acd13 epoll cleanups: e... |
1392 |
} |
1da177e4c Linux-2.6.12-rc2 |
1393 |
|
7699acd13 epoll cleanups: e... |
1394 1395 |
/* We have to call this outside the lock */ if (pwake) |
5071f97ec epoll: fix epoll'... |
1396 |
ep_poll_safewake(&ep->poll_wait); |
1da177e4c Linux-2.6.12-rc2 |
1397 |
|
7699acd13 epoll cleanups: e... |
1398 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1399 |
} |
296e236e9 epoll: fix epoll'... |
1400 1401 |
static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head, void *priv) |
1da177e4c Linux-2.6.12-rc2 |
1402 |
{ |
5071f97ec epoll: fix epoll'... |
1403 1404 |
struct ep_send_events_data *esed = priv; int eventcnt; |
296e236e9 epoll: fix epoll'... |
1405 |
unsigned int revents; |
5071f97ec epoll: fix epoll'... |
1406 1407 |
struct epitem *epi; struct epoll_event __user *uevent; |
eea1d5859 epoll: use RCU to... |
1408 |
struct wakeup_source *ws; |
626cf2366 poll: add poll_re... |
1409 1410 1411 |
poll_table pt; init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1412 |
|
296e236e9 epoll: fix epoll'... |
1413 |
/* |
5071f97ec epoll: fix epoll'... |
1414 1415 1416 |
* 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'... |
1417 |
*/ |
5071f97ec epoll: fix epoll'... |
1418 1419 1420 |
for (eventcnt = 0, uevent = esed->events; !list_empty(head) && eventcnt < esed->maxevents;) { epi = list_first_entry(head, struct epitem, rdllink); |
d47de16c7 fix epoll single ... |
1421 |
|
4d7e30d98 epoll: Add a flag... |
1422 1423 1424 1425 1426 1427 1428 1429 1430 |
/* * 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... |
1431 1432 1433 1434 1435 1436 |
ws = ep_wakeup_source(epi); if (ws) { if (ws->active) __pm_stay_awake(ep->ws); __pm_relax(ws); } |
d47de16c7 fix epoll single ... |
1437 |
list_del_init(&epi->rdllink); |
1da177e4c Linux-2.6.12-rc2 |
1438 |
|
450d89ec0 epoll: cleanup: h... |
1439 |
revents = ep_item_poll(epi, &pt); |
5071f97ec epoll: fix epoll'... |
1440 |
|
296e236e9 epoll: fix epoll'... |
1441 |
/* |
5071f97ec epoll: fix epoll'... |
1442 1443 1444 1445 |
* If the event mask intersect the caller-requested one, * deliver the event to userspace. Again, ep_scan_ready_list() * is holding "mtx", so no operations coming from userspace * can change the item. |
296e236e9 epoll: fix epoll'... |
1446 1447 |
*/ if (revents) { |
5071f97ec epoll: fix epoll'... |
1448 |
if (__put_user(revents, &uevent->events) || |
d03058828 epoll: remember t... |
1449 1450 |
__put_user(epi->event.data, &uevent->data)) { list_add(&epi->rdllink, head); |
eea1d5859 epoll: use RCU to... |
1451 |
ep_pm_stay_awake(epi); |
296e236e9 epoll: fix epoll'... |
1452 |
return eventcnt ? eventcnt : -EFAULT; |
d03058828 epoll: remember t... |
1453 |
} |
296e236e9 epoll: fix epoll'... |
1454 |
eventcnt++; |
5071f97ec epoll: fix epoll'... |
1455 |
uevent++; |
296e236e9 epoll: fix epoll'... |
1456 1457 1458 1459 1460 1461 1462 1463 |
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 |
25985edce Fix common misspe... |
1464 |
* availability. At this point, no one can insert |
296e236e9 epoll: fix epoll'... |
1465 1466 1467 1468 1469 1470 |
* 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); |
eea1d5859 epoll: use RCU to... |
1471 |
ep_pm_stay_awake(epi); |
296e236e9 epoll: fix epoll'... |
1472 1473 1474 |
} } } |
5071f97ec epoll: fix epoll'... |
1475 1476 1477 |
return eventcnt; } |
d47de16c7 fix epoll single ... |
1478 |
|
296e236e9 epoll: fix epoll'... |
1479 1480 |
static int ep_send_events(struct eventpoll *ep, struct epoll_event __user *events, int maxevents) |
5071f97ec epoll: fix epoll'... |
1481 1482 |
{ struct ep_send_events_data esed; |
1da177e4c Linux-2.6.12-rc2 |
1483 |
|
5071f97ec epoll: fix epoll'... |
1484 1485 |
esed.maxevents = maxevents; esed.events = events; |
6192bd536 epoll: optimizati... |
1486 |
|
67347fe4e epoll: do not tak... |
1487 |
return ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false); |
1da177e4c Linux-2.6.12-rc2 |
1488 |
} |
0781b909b epoll: epoll_wait... |
1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 |
static inline struct timespec ep_set_mstimeout(long ms) { struct timespec now, ts = { .tv_sec = ms / MSEC_PER_SEC, .tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC), }; ktime_get_ts(&now); return timespec_add_safe(now, ts); } |
f4d93ad74 epoll: fix compil... |
1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 |
/** * 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 |
1516 1517 1518 |
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int maxevents, long timeout) { |
f4d93ad74 epoll: fix compil... |
1519 |
int res = 0, eavail, timed_out = 0; |
1da177e4c Linux-2.6.12-rc2 |
1520 |
unsigned long flags; |
f4d93ad74 epoll: fix compil... |
1521 |
long slack = 0; |
1da177e4c Linux-2.6.12-rc2 |
1522 |
wait_queue_t wait; |
95aac7b1c epoll: make epoll... |
1523 1524 1525 |
ktime_t expires, *to = NULL; if (timeout > 0) { |
0781b909b epoll: epoll_wait... |
1526 |
struct timespec end_time = ep_set_mstimeout(timeout); |
95aac7b1c epoll: make epoll... |
1527 1528 1529 1530 |
slack = select_estimate_accuracy(&end_time); to = &expires; *to = timespec_to_ktime(end_time); } else if (timeout == 0) { |
f4d93ad74 epoll: fix compil... |
1531 1532 1533 1534 |
/* * Avoid the unnecessary trip to the wait queue loop, if the * caller specified a non blocking operation. */ |
95aac7b1c epoll: make epoll... |
1535 |
timed_out = 1; |
f4d93ad74 epoll: fix compil... |
1536 1537 |
spin_lock_irqsave(&ep->lock, flags); goto check_events; |
95aac7b1c epoll: make epoll... |
1538 |
} |
1da177e4c Linux-2.6.12-rc2 |
1539 |
|
f4d93ad74 epoll: fix compil... |
1540 |
fetch_events: |
c7ea76302 epoll locks chang... |
1541 |
spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1542 |
|
3fb0e584a epoll: move ready... |
1543 |
if (!ep_events_available(ep)) { |
1da177e4c Linux-2.6.12-rc2 |
1544 1545 1546 1547 1548 1549 |
/* * We don't have any available event to return to the caller. * We need to sleep here, and we will be wake up by * ep_poll_callback() when events will become available. */ init_waitqueue_entry(&wait, current); |
a93d2f174 sched, wait: Use ... |
1550 |
__add_wait_queue_exclusive(&ep->wq, &wait); |
1da177e4c Linux-2.6.12-rc2 |
1551 1552 1553 1554 1555 1556 1557 1558 |
for (;;) { /* * We don't want to sleep if the ep_poll_callback() sends us * a wakeup in between. That's why we set the task state * to TASK_INTERRUPTIBLE before doing the checks. */ set_current_state(TASK_INTERRUPTIBLE); |
3fb0e584a epoll: move ready... |
1559 |
if (ep_events_available(ep) || timed_out) |
1da177e4c Linux-2.6.12-rc2 |
1560 1561 1562 1563 1564 |
break; if (signal_pending(current)) { res = -EINTR; break; } |
c7ea76302 epoll locks chang... |
1565 |
spin_unlock_irqrestore(&ep->lock, flags); |
c511851de Revert "epoll: us... |
1566 |
if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) |
95aac7b1c epoll: make epoll... |
1567 |
timed_out = 1; |
c7ea76302 epoll locks chang... |
1568 |
spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1569 |
} |
3419b23a9 [PATCH] epoll: us... |
1570 |
__remove_wait_queue(&ep->wq, &wait); |
1da177e4c Linux-2.6.12-rc2 |
1571 1572 1573 |
set_current_state(TASK_RUNNING); } |
f4d93ad74 epoll: fix compil... |
1574 |
check_events: |
1da177e4c Linux-2.6.12-rc2 |
1575 |
/* Is it worth to try to dig for events ? */ |
3fb0e584a epoll: move ready... |
1576 |
eavail = ep_events_available(ep); |
1da177e4c Linux-2.6.12-rc2 |
1577 |
|
c7ea76302 epoll locks chang... |
1578 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1579 1580 1581 1582 1583 1584 1585 |
/* * 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... |
1586 |
!(res = ep_send_events(ep, events, maxevents)) && !timed_out) |
f4d93ad74 epoll: fix compil... |
1587 |
goto fetch_events; |
1da177e4c Linux-2.6.12-rc2 |
1588 1589 1590 |
return res; } |
22bacca48 epoll: prevent cr... |
1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 |
/** * 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 |
1611 |
struct eventpoll *ep_tovisit; |
22bacca48 epoll: prevent cr... |
1612 1613 |
struct rb_node *rbp; struct epitem *epi; |
d8805e633 epoll: fix spurio... |
1614 |
mutex_lock_nested(&ep->mtx, call_nests + 1); |
28d82dc1c epoll: limit paths |
1615 1616 |
ep->visited = 1; list_add(&ep->visited_list_link, &visited_list); |
22bacca48 epoll: prevent cr... |
1617 1618 1619 |
for (rbp = rb_first(&ep->rbr); rbp; rbp = rb_next(rbp)) { epi = rb_entry(rbp, struct epitem, rbn); if (unlikely(is_file_epoll(epi->ffd.file))) { |
28d82dc1c epoll: limit paths |
1620 1621 1622 |
ep_tovisit = epi->ffd.file->private_data; if (ep_tovisit->visited) continue; |
22bacca48 epoll: prevent cr... |
1623 |
error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, |
28d82dc1c epoll: limit paths |
1624 1625 |
ep_loop_check_proc, epi->ffd.file, ep_tovisit, current); |
22bacca48 epoll: prevent cr... |
1626 1627 |
if (error != 0) break; |
28d82dc1c epoll: limit paths |
1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 |
} 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(). */ if (list_empty(&epi->ffd.file->f_tfile_llink)) list_add(&epi->ffd.file->f_tfile_llink, &tfile_check_list); |
22bacca48 epoll: prevent cr... |
1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 |
} } 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) { |
28d82dc1c epoll: limit paths |
1660 1661 1662 1663 |
int ret; struct eventpoll *ep_cur, *ep_next; ret = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, |
22bacca48 epoll: prevent cr... |
1664 |
ep_loop_check_proc, file, ep, current); |
28d82dc1c epoll: limit paths |
1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 |
/* clear visited list */ list_for_each_entry_safe(ep_cur, ep_next, &visited_list, visited_list_link) { ep_cur->visited = 0; list_del(&ep_cur->visited_list_link); } return ret; } 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); } INIT_LIST_HEAD(&tfile_check_list); |
22bacca48 epoll: prevent cr... |
1685 |
} |
7699acd13 epoll cleanups: e... |
1686 |
/* |
523723bb5 fs/eventpoll.c: f... |
1687 |
* Open an eventpoll file descriptor. |
7699acd13 epoll cleanups: e... |
1688 |
*/ |
5a8a82b1d [CVE-2009-0029] S... |
1689 |
SYSCALL_DEFINE1(epoll_create1, int, flags) |
7699acd13 epoll cleanups: e... |
1690 |
{ |
28d82dc1c epoll: limit paths |
1691 |
int error, fd; |
bb57c3edc epoll: remove deb... |
1692 |
struct eventpoll *ep = NULL; |
28d82dc1c epoll: limit paths |
1693 |
struct file *file; |
7699acd13 epoll cleanups: e... |
1694 |
|
e38b36f32 flag parameters: ... |
1695 1696 |
/* Check the EPOLL_* constant for consistency. */ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC); |
296e236e9 epoll: fix epoll'... |
1697 1698 |
if (flags & ~EPOLL_CLOEXEC) return -EINVAL; |
7699acd13 epoll cleanups: e... |
1699 |
/* |
bb57c3edc epoll: remove deb... |
1700 |
* Create the internal data structure ("struct eventpoll"). |
7699acd13 epoll cleanups: e... |
1701 |
*/ |
9fe5ad9c8 flag parameters a... |
1702 |
error = ep_alloc(&ep); |
bb57c3edc epoll: remove deb... |
1703 1704 |
if (error < 0) return error; |
7699acd13 epoll cleanups: e... |
1705 1706 |
/* * Creates all the items needed to setup an eventpoll file. That is, |
2030a42ce [PATCH] sanitize ... |
1707 |
* a file structure and a free file descriptor. |
7699acd13 epoll cleanups: e... |
1708 |
*/ |
28d82dc1c epoll: limit paths |
1709 1710 1711 1712 1713 1714 |
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... |
1715 |
O_RDWR | (flags & O_CLOEXEC)); |
28d82dc1c epoll: limit paths |
1716 1717 1718 1719 |
if (IS_ERR(file)) { error = PTR_ERR(file); goto out_free_fd; } |
28d82dc1c epoll: limit paths |
1720 |
ep->file = file; |
98022748f eventpoll: use-af... |
1721 |
fd_install(fd, file); |
28d82dc1c epoll: limit paths |
1722 1723 1724 1725 1726 1727 |
return fd; out_free_fd: put_unused_fd(fd); out_free_ep: ep_free(ep); |
bb57c3edc epoll: remove deb... |
1728 |
return error; |
7699acd13 epoll cleanups: e... |
1729 |
} |
5a8a82b1d [CVE-2009-0029] S... |
1730 |
SYSCALL_DEFINE1(epoll_create, int, size) |
a0998b50c flag parameters: ... |
1731 |
{ |
bfe3891a5 epoll: fix size c... |
1732 |
if (size <= 0) |
9fe5ad9c8 flag parameters a... |
1733 1734 1735 |
return -EINVAL; return sys_epoll_create1(0); |
a0998b50c flag parameters: ... |
1736 |
} |
7699acd13 epoll cleanups: e... |
1737 1738 1739 |
/* * The following function implements the controller interface for * the eventpoll file that enables the insertion/removal/change of |
67647d0fb epoll: fix some c... |
1740 |
* file descriptors inside the interest set. |
7699acd13 epoll cleanups: e... |
1741 |
*/ |
5a8a82b1d [CVE-2009-0029] S... |
1742 1743 |
SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event __user *, event) |
7699acd13 epoll cleanups: e... |
1744 1745 |
{ int error; |
67347fe4e epoll: do not tak... |
1746 |
int full_check = 0; |
7e3fb5842 switch epoll_ctl(... |
1747 |
struct fd f, tf; |
7699acd13 epoll cleanups: e... |
1748 1749 1750 |
struct eventpoll *ep; struct epitem *epi; struct epoll_event epds; |
67347fe4e epoll: do not tak... |
1751 |
struct eventpoll *tep = NULL; |
7699acd13 epoll cleanups: e... |
1752 |
|
7699acd13 epoll cleanups: e... |
1753 1754 1755 1756 |
error = -EFAULT; if (ep_op_has_event(op) && copy_from_user(&epds, event, sizeof(struct epoll_event))) goto error_return; |
7699acd13 epoll cleanups: e... |
1757 |
error = -EBADF; |
7e3fb5842 switch epoll_ctl(... |
1758 1759 |
f = fdget(epfd); if (!f.file) |
7699acd13 epoll cleanups: e... |
1760 1761 1762 |
goto error_return; /* Get the "struct file *" for the target file */ |
7e3fb5842 switch epoll_ctl(... |
1763 1764 |
tf = fdget(fd); if (!tf.file) |
7699acd13 epoll cleanups: e... |
1765 1766 1767 1768 |
goto error_fput; /* The target file descriptor must support poll */ error = -EPERM; |
72c2d5319 file->f_op is nev... |
1769 |
if (!tf.file->f_op->poll) |
7699acd13 epoll cleanups: e... |
1770 |
goto error_tgt_fput; |
4d7e30d98 epoll: Add a flag... |
1771 |
/* Check if EPOLLWAKEUP is allowed */ |
c680e41b3 eventpoll: fix un... |
1772 1773 |
if (ep_op_has_event(op)) ep_take_care_of_epollwakeup(&epds); |
4d7e30d98 epoll: Add a flag... |
1774 |
|
7699acd13 epoll cleanups: e... |
1775 1776 1777 1778 1779 1780 |
/* * 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(... |
1781 |
if (f.file == tf.file || !is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
1782 1783 1784 1785 1786 1787 |
goto error_tgt_fput; /* * At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
7e3fb5842 switch epoll_ctl(... |
1788 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
1789 |
|
22bacca48 epoll: prevent cr... |
1790 1791 1792 |
/* * 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 |
1793 1794 1795 1796 |
* 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... |
1797 |
* |
67347fe4e epoll: do not tak... |
1798 1799 1800 1801 1802 1803 |
* 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... |
1804 |
*/ |
67347fe4e epoll: do not tak... |
1805 |
mutex_lock_nested(&ep->mtx, 0); |
28d82dc1c epoll: limit paths |
1806 |
if (op == EPOLL_CTL_ADD) { |
67347fe4e epoll: do not tak... |
1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 |
if (!list_empty(&f.file->f_ep_links) || is_file_epoll(tf.file)) { full_check = 1; mutex_unlock(&ep->mtx); mutex_lock(&epmutex); if (is_file_epoll(tf.file)) { error = -ELOOP; if (ep_loop_check(ep, tf.file) != 0) { clear_tfile_check_list(); goto error_tgt_fput; } } else list_add(&tf.file->f_tfile_llink, &tfile_check_list); mutex_lock_nested(&ep->mtx, 0); if (is_file_epoll(tf.file)) { tep = tf.file->private_data; mutex_lock_nested(&tep->mtx, 1); |
13d518074 epoll: clear the ... |
1825 |
} |
67347fe4e epoll: do not tak... |
1826 1827 |
} } |
7699acd13 epoll cleanups: e... |
1828 |
|
67647d0fb epoll: fix some c... |
1829 1830 1831 1832 1833 |
/* * 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(... |
1834 |
epi = ep_find(ep, tf.file, fd); |
7699acd13 epoll cleanups: e... |
1835 1836 1837 1838 1839 1840 |
error = -EINVAL; switch (op) { case EPOLL_CTL_ADD: if (!epi) { epds.events |= POLLERR | POLLHUP; |
67347fe4e epoll: do not tak... |
1841 |
error = ep_insert(ep, &epds, tf.file, fd, full_check); |
7699acd13 epoll cleanups: e... |
1842 1843 |
} else error = -EEXIST; |
67347fe4e epoll: do not tak... |
1844 1845 |
if (full_check) clear_tfile_check_list(); |
7699acd13 epoll cleanups: e... |
1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 |
break; case EPOLL_CTL_DEL: if (epi) error = ep_remove(ep, epi); else error = -ENOENT; break; case EPOLL_CTL_MOD: if (epi) { epds.events |= POLLERR | POLLHUP; error = ep_modify(ep, epi, &epds); } else error = -ENOENT; break; } |
67347fe4e epoll: do not tak... |
1861 1862 |
if (tep != NULL) mutex_unlock(&tep->mtx); |
d47de16c7 fix epoll single ... |
1863 |
mutex_unlock(&ep->mtx); |
7699acd13 epoll cleanups: e... |
1864 1865 |
error_tgt_fput: |
67347fe4e epoll: do not tak... |
1866 |
if (full_check) |
22bacca48 epoll: prevent cr... |
1867 |
mutex_unlock(&epmutex); |
7e3fb5842 switch epoll_ctl(... |
1868 |
fdput(tf); |
7699acd13 epoll cleanups: e... |
1869 |
error_fput: |
7e3fb5842 switch epoll_ctl(... |
1870 |
fdput(f); |
7699acd13 epoll cleanups: e... |
1871 |
error_return: |
7699acd13 epoll cleanups: e... |
1872 1873 1874 1875 1876 1877 1878 1879 |
return error; } /* * Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_wait(2). */ |
5a8a82b1d [CVE-2009-0029] S... |
1880 1881 |
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout) |
7699acd13 epoll cleanups: e... |
1882 |
{ |
2903ff019 switch simple cas... |
1883 1884 |
int error; struct fd f; |
7699acd13 epoll cleanups: e... |
1885 |
struct eventpoll *ep; |
7699acd13 epoll cleanups: e... |
1886 1887 1888 1889 1890 |
/* 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 */ |
2903ff019 switch simple cas... |
1891 1892 |
if (!access_ok(VERIFY_WRITE, events, maxevents * sizeof(struct epoll_event))) return -EFAULT; |
7699acd13 epoll cleanups: e... |
1893 1894 |
/* Get the "struct file *" for the eventpoll file */ |
2903ff019 switch simple cas... |
1895 1896 1897 |
f = fdget(epfd); if (!f.file) return -EBADF; |
7699acd13 epoll cleanups: e... |
1898 1899 1900 1901 1902 1903 |
/* * 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... |
1904 |
if (!is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
1905 1906 1907 1908 1909 1910 |
goto error_fput; /* * At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
2903ff019 switch simple cas... |
1911 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
1912 1913 1914 1915 1916 |
/* Time to fish for events ... */ error = ep_poll(ep, events, maxevents, timeout); error_fput: |
2903ff019 switch simple cas... |
1917 |
fdput(f); |
7699acd13 epoll cleanups: e... |
1918 1919 |
return error; } |
7699acd13 epoll cleanups: e... |
1920 1921 1922 1923 |
/* * 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... |
1924 1925 1926 |
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... |
1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 |
{ int error; sigset_t ksigmask, sigsaved; /* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ if (sigmask) { if (sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) return -EFAULT; |
77d559180 signals: eventpol... |
1940 1941 |
sigsaved = current->blocked; set_current_blocked(&ksigmask); |
7699acd13 epoll cleanups: e... |
1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 |
} error = sys_epoll_wait(epfd, events, maxevents, timeout); /* * If we changed the signal mask, we need to restore the original one. * In case we've got a signal while waiting, we do not restore the * signal mask yet, and we allow do_signal() to deliver the signal on * the way back to userspace, before the signal mask is restored. */ if (sigmask) { if (error == -EINTR) { memcpy(¤t->saved_sigmask, &sigsaved, |
c7ea76302 epoll locks chang... |
1955 |
sizeof(sigsaved)); |
4e4c22c71 signals: add set_... |
1956 |
set_restore_sigmask(); |
7699acd13 epoll cleanups: e... |
1957 |
} else |
77d559180 signals: eventpol... |
1958 |
set_current_blocked(&sigsaved); |
7699acd13 epoll cleanups: e... |
1959 1960 1961 1962 |
} return error; } |
35280bd4a switch epoll_pwai... |
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 |
#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; compat_sigset_t csigmask; sigset_t ksigmask, sigsaved; /* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ if (sigmask) { if (sigsetsize != sizeof(compat_sigset_t)) return -EINVAL; if (copy_from_user(&csigmask, sigmask, sizeof(csigmask))) return -EFAULT; sigset_from_compat(&ksigmask, &csigmask); |
77d559180 signals: eventpol... |
1984 1985 |
sigsaved = current->blocked; set_current_blocked(&ksigmask); |
35280bd4a switch epoll_pwai... |
1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 |
} err = sys_epoll_wait(epfd, events, maxevents, timeout); /* * If we changed the signal mask, we need to restore the original one. * In case we've got a signal while waiting, we do not restore the * signal mask yet, and we allow do_signal() to deliver the signal on * the way back to userspace, before the signal mask is restored. */ if (sigmask) { if (err == -EINTR) { memcpy(¤t->saved_sigmask, &sigsaved, sizeof(sigsaved)); set_restore_sigmask(); } else |
77d559180 signals: eventpol... |
2002 |
set_current_blocked(&sigsaved); |
35280bd4a switch epoll_pwai... |
2003 2004 2005 2006 2007 |
} return err; } #endif |
1da177e4c Linux-2.6.12-rc2 |
2008 2009 |
static int __init eventpoll_init(void) { |
7ef9964e6 epoll: introduce ... |
2010 2011 2012 |
struct sysinfo si; si_meminfo(&si); |
9df04e1f2 epoll: drop max_u... |
2013 2014 2015 2016 |
/* * 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 ... |
2017 |
EP_ITEM_COST; |
52bd19f76 epoll: convert ma... |
2018 |
BUG_ON(max_user_watches < 0); |
1da177e4c Linux-2.6.12-rc2 |
2019 |
|
22bacca48 epoll: prevent cr... |
2020 2021 2022 2023 2024 |
/* * Initialize the structure used to perform epoll file descriptor * inclusion loops checks. */ ep_nested_calls_init(&poll_loop_ncalls); |
1da177e4c Linux-2.6.12-rc2 |
2025 |
/* Initialize the structure used to perform safe poll wait head wake ups */ |
5071f97ec epoll: fix epoll'... |
2026 2027 2028 2029 |
ep_nested_calls_init(&poll_safewake_ncalls); /* Initialize the structure used to perform file's f_op->poll() calls */ ep_nested_calls_init(&poll_readywalk_ncalls); |
1da177e4c Linux-2.6.12-rc2 |
2030 |
|
39732ca5a epoll: trim epite... |
2031 2032 2033 2034 2035 |
/* * 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 |
2036 2037 |
/* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), |
bb57c3edc epoll: remove deb... |
2038 |
0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2039 2040 2041 |
/* Allocates slab cache used to allocate "struct eppoll_entry" */ pwq_cache = kmem_cache_create("eventpoll_pwq", |
bb57c3edc epoll: remove deb... |
2042 |
sizeof(struct eppoll_entry), 0, SLAB_PANIC, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2043 |
|
1da177e4c Linux-2.6.12-rc2 |
2044 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
2045 |
} |
cea692418 epoll cleanups: e... |
2046 |
fs_initcall(eventpoll_init); |