Merge branch 'akpm' (Fixes from Andrew)

Merge misc fixes from Andrew Morton: "Five fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (5 patches) h8300: add missing L1_CACHE_SHIFT mm: bugfix: set current->reclaim_state to NULL while returning from kswapd() fanotify: fix missing break revert "epoll: support for disabling items, and a self-test app" checkpatch: improve network block comment style checking

Merge branch 'akpm' (Fixes from Andrew)
Merge misc fixes from Andrew Morton: "Five fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (5 patches) h8300: add missing L1_CACHE_SHIFT mm: bugfix: set current->reclaim_state to NULL while returning from kswapd() fanotify: fix missing break revert "epoll: support for disabling items, and a self-test app" checkpatch: improve network block comment style checking
Linus Torvalds
2 parents c0cba03baa 6893f5675f
Showing 9 changed files Side-by-side Diff
arch/h8300/include/asm/cache.h
fs/eventpoll.c
fs/notify/fanotify/fanotify.c
include/uapi/linux/eventpoll.h
mm/vmscan.c
scripts/checkpatch.pl
tools/testing/selftests/Makefile
tools/testing/selftests/epoll/Makefile
tools/testing/selftests/epoll/test_epoll.c
@@ -2,7 +2,8 @@
 #define __ARCH_H8300_CACHE_H
  
 /* bytes per L1 cache line */
-#define        L1_CACHE_BYTES  4
+#define        L1_CACHE_SHIFT  2
+#define        L1_CACHE_BYTES  (1 << L1_CACHE_SHIFT)
  
 /* m68k-elf-gcc  2.95.2 doesn't like these */
  
@@ -346,7 +346,7 @@
 /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */
 static inline int ep_op_has_event(int op)
 {
-	return op == EPOLL_CTL_ADD || op == EPOLL_CTL_MOD;
+	return op != EPOLL_CTL_DEL;
 }
  
 /* Initialize the poll safe wake up structure */
@@ -676,34 +676,6 @@
 	return 0;
 }
  
-/*
- * Disables a "struct epitem" in the eventpoll set. Returns -EBUSY if the item
- * had no event flags set, indicating that another thread may be currently
- * handling that item's events (in the case that EPOLLONESHOT was being
- * used). Otherwise a zero result indicates that the item has been disabled
- * from receiving events. A disabled item may be re-enabled via
- * EPOLL_CTL_MOD. Must be called with "mtx" held.
- */
-static int ep_disable(struct eventpoll *ep, struct epitem *epi)
-{
-	int result = 0;
-	unsigned long flags;
-
-	spin_lock_irqsave(&ep->lock, flags);
-	if (epi->event.events & ~EP_PRIVATE_BITS) {
-		if (ep_is_linked(&epi->rdllink))
-			list_del_init(&epi->rdllink);
-		/* Ensure ep_poll_callback will not add epi back onto ready
-		   list: */
-		epi->event.events &= EP_PRIVATE_BITS;
-		}
-	else
-		result = -EBUSY;
-	spin_unlock_irqrestore(&ep->lock, flags);
-
-	return result;
-}
-
 static void ep_free(struct eventpoll *ep)
 {
 	struct rb_node *rbp;
@@ -1048,6 +1020,8 @@
 	rb_insert_color(&epi->rbn, &ep->rbr);
 }
  
+
+
 #define PATH_ARR_SIZE 5
 /*
  * These are the number paths of length 1 to 5, that we are allowing to emanate
@@ -1811,12 +1785,6 @@
 			epds.events |= POLLERR | POLLHUP;
 			error = ep_modify(ep, epi, &epds);
 		} else
-			error = -ENOENT;
-		break;
-	case EPOLL_CTL_DISABLE:
-		if (epi)
-			error = ep_disable(ep, epi);
-		else
 			error = -ENOENT;
 		break;
 	}
@@ -21,6 +21,7 @@
 			if ((old->path.mnt == new->path.mnt) &&
 			    (old->path.dentry == new->path.dentry))
 				return true;
+			break;
 		case (FSNOTIFY_EVENT_NONE):
 			return true;
 		default:
@@ -25,7 +25,6 @@
 #define EPOLL_CTL_ADD 1
 #define EPOLL_CTL_DEL 2
 #define EPOLL_CTL_MOD 3
-#define EPOLL_CTL_DISABLE 4
  
 /*
  * Request the handling of system wakeup events so as to prevent system suspends
@@ -3017,6 +3017,8 @@
 						&balanced_classzone_idx);
 		}
 	}
+
+	current->reclaim_state = NULL;
 	return 0;
 }
  
@@ -1890,8 +1890,10 @@
 		}
  
 		if ($realfile =~ m@^(drivers/net/|net/)@ &&
-		    $rawline !~ m@^\+[ \t]*(\/\*|\*\/)@ &&
-		    $rawline =~ m@^\+[ \t]*.+\*\/[ \t]*$@) {
+		    $rawline !~ m@^\+[ \t]*\*/[ \t]*$@ &&	#trailing */
+		    $rawline !~ m@^\+.*/\*.*\*/[ \t]*$@ &&	#inline /*...*/
+		    $rawline !~ m@^\+.*\*{2,}/[ \t]*$@ &&	#trailing **/
+		    $rawline =~ m@^\+[ \t]*.+\*\/[ \t]*$@) {	#non blank */
 			WARN("NETWORKING_BLOCK_COMMENT_STYLE",
 			     "networking block comments put the trailing */ on a separate line\n" . $herecurr);
 		}
-TARGETS = breakpoints kcmp mqueue vm cpu-hotplug memory-hotplug epoll
+TARGETS = breakpoints kcmp mqueue vm cpu-hotplug memory-hotplug
  
 all:
 	for TARGET in $(TARGETS); do \
-# Makefile for epoll selftests
-
-all: test_epoll
-%: %.c
-	gcc -pthread -g -o $@ $^
-
-run_tests: all
-	./test_epoll
-
-clean:
-	$(RM) test_epoll
-/*
- *  tools/testing/selftests/epoll/test_epoll.c
- *
- *  Copyright 2012 Adobe Systems Incorporated
- *
- *  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.
- *
- *  Paton J. Lewis <palewis@adobe.com>
- *
- */
-
-#include <errno.h>
-#include <fcntl.h>
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/epoll.h>
-#include <sys/socket.h>
-
-/*
- * A pointer to an epoll_item_private structure will be stored in the epoll
- * item's event structure so that we can get access to the epoll_item_private
- * data after calling epoll_wait:
- */
-struct epoll_item_private {
-	int index;  /* Position of this struct within the epoll_items array. */
-	int fd;
-	uint32_t events;
-	pthread_mutex_t mutex;  /* Guards the following variables... */
-	int stop;
-	int status;  /* Stores any error encountered while handling item. */
-	/* The following variable allows us to test whether we have encountered
-	   a problem while attempting to cancel and delete the associated
-	   event. When the test program exits, 'deleted' should be exactly
-	   one. If it is greater than one, then the failed test reflects a real
-	   world situation where we would have tried to access the epoll item's
-	   private data after deleting it: */
-	int deleted;
-};
-
-struct epoll_item_private *epoll_items;
-
-/*
- * Delete the specified item from the epoll set. In a real-world secneario this
- * is where we would free the associated data structure, but in this testing
- * environment we retain the structure so that we can test for double-deletion:
- */
-void delete_item(int index)
-{
-	__sync_fetch_and_add(&epoll_items[index].deleted, 1);
-}
-
-/*
- * A pointer to a read_thread_data structure will be passed as the argument to
- * each read thread:
- */
-struct read_thread_data {
-	int stop;
-	int status;  /* Indicates any error encountered by the read thread. */
-	int epoll_set;
-};
-
-/*
- * The function executed by the read threads:
- */
-void *read_thread_function(void *function_data)
-{
-	struct read_thread_data *thread_data =
-		(struct read_thread_data *)function_data;
-	struct epoll_event event_data;
-	struct epoll_item_private *item_data;
-	char socket_data;
-
-	/* Handle events until we encounter an error or this thread's 'stop'
-	   condition is set: */
-	while (1) {
-		int result = epoll_wait(thread_data->epoll_set,
-					&event_data,
-					1,	/* Number of desired events */
-					1000);  /* Timeout in ms */
-		if (result < 0) {
-			/* Breakpoints signal all threads. Ignore that while
-			   debugging: */
-			if (errno == EINTR)
-				continue;
-			thread_data->status = errno;
-			return 0;
-		} else if (thread_data->stop)
-			return 0;
-		else if (result == 0)  /* Timeout */
-			continue;
-
-		/* We need the mutex here because checking for the stop
-		   condition and re-enabling the epoll item need to be done
-		   together as one atomic operation when EPOLL_CTL_DISABLE is
-		   available: */
-		item_data = (struct epoll_item_private *)event_data.data.ptr;
-		pthread_mutex_lock(&item_data->mutex);
-
-		/* Remove the item from the epoll set if we want to stop
-		   handling that event: */
-		if (item_data->stop)
-			delete_item(item_data->index);
-		else {
-			/* Clear the data that was written to the other end of
-			   our non-blocking socket: */
-			do {
-				if (read(item_data->fd, &socket_data, 1) < 1) {
-					if ((errno == EAGAIN) ||
-					    (errno == EWOULDBLOCK))
-						break;
-					else
-						goto error_unlock;
-				}
-			} while (item_data->events & EPOLLET);
-
-			/* The item was one-shot, so re-enable it: */
-			event_data.events = item_data->events;
-			if (epoll_ctl(thread_data->epoll_set,
-						  EPOLL_CTL_MOD,
-						  item_data->fd,
-						  &event_data) < 0)
-				goto error_unlock;
-		}
-
-		pthread_mutex_unlock(&item_data->mutex);
-	}
-
-error_unlock:
-	thread_data->status = item_data->status = errno;
-	pthread_mutex_unlock(&item_data->mutex);
-	return 0;
-}
-
-/*
- * A pointer to a write_thread_data structure will be passed as the argument to
- * the write thread:
- */
-struct write_thread_data {
-	int stop;
-	int status;  /* Indicates any error encountered by the write thread. */
-	int n_fds;
-	int *fds;
-};
-
-/*
- * The function executed by the write thread. It writes a single byte to each
- * socket in turn until the stop condition for this thread is set. If writing to
- * a socket would block (i.e. errno was EAGAIN), we leave that socket alone for
- * the moment and just move on to the next socket in the list. We don't care
- * about the order in which we deliver events to the epoll set. In fact we don't
- * care about the data we're writing to the pipes at all; we just want to
- * trigger epoll events:
- */
-void *write_thread_function(void *function_data)
-{
-	const char data = 'X';
-	int index;
-	struct write_thread_data *thread_data =
-		(struct write_thread_data *)function_data;
-	while (!thread_data->stop)
-		for (index = 0;
-		     !thread_data->stop && (index < thread_data->n_fds);
-		     ++index)
-			if ((write(thread_data->fds[index], &data, 1) < 1) &&
-				(errno != EAGAIN) &&
-				(errno != EWOULDBLOCK)) {
-				thread_data->status = errno;
-				return;
-			}
-}
-
-/*
- * Arguments are currently ignored:
- */
-int main(int argc, char **argv)
-{
-	const int n_read_threads = 100;
-	const int n_epoll_items = 500;
-	int index;
-	int epoll_set = epoll_create1(0);
-	struct write_thread_data write_thread_data = {
-		0, 0, n_epoll_items, malloc(n_epoll_items * sizeof(int))
-	};
-	struct read_thread_data *read_thread_data =
-		malloc(n_read_threads * sizeof(struct read_thread_data));
-	pthread_t *read_threads = malloc(n_read_threads * sizeof(pthread_t));
-	pthread_t write_thread;
-
-	printf("-----------------\n");
-	printf("Runing test_epoll\n");
-	printf("-----------------\n");
-
-	epoll_items = malloc(n_epoll_items * sizeof(struct epoll_item_private));
-
-	if (epoll_set < 0 || epoll_items == 0 || write_thread_data.fds == 0 ||
-		read_thread_data == 0 || read_threads == 0)
-		goto error;
-
-	if (sysconf(_SC_NPROCESSORS_ONLN) < 2) {
-		printf("Error: please run this test on a multi-core system.\n");
-		goto error;
-	}
-
-	/* Create the socket pairs and epoll items: */
-	for (index = 0; index < n_epoll_items; ++index) {
-		int socket_pair[2];
-		struct epoll_event event_data;
-		if (socketpair(AF_UNIX,
-			       SOCK_STREAM | SOCK_NONBLOCK,
-			       0,
-			       socket_pair) < 0)
-			goto error;
-		write_thread_data.fds[index] = socket_pair[0];
-		epoll_items[index].index = index;
-		epoll_items[index].fd = socket_pair[1];
-		if (pthread_mutex_init(&epoll_items[index].mutex, NULL) != 0)
-			goto error;
-		/* We always use EPOLLONESHOT because this test is currently
-		   structured to demonstrate the need for EPOLL_CTL_DISABLE,
-		   which only produces useful information in the EPOLLONESHOT
-		   case (without EPOLLONESHOT, calling epoll_ctl with
-		   EPOLL_CTL_DISABLE will never return EBUSY). If support for
-		   testing events without EPOLLONESHOT is desired, it should
-		   probably be implemented in a separate unit test. */
-		epoll_items[index].events = EPOLLIN | EPOLLONESHOT;
-		if (index < n_epoll_items / 2)
-			epoll_items[index].events |= EPOLLET;
-		epoll_items[index].stop = 0;
-		epoll_items[index].status = 0;
-		epoll_items[index].deleted = 0;
-		event_data.events = epoll_items[index].events;
-		event_data.data.ptr = &epoll_items[index];
-		if (epoll_ctl(epoll_set,
-			      EPOLL_CTL_ADD,
-			      epoll_items[index].fd,
-			      &event_data) < 0)
-			goto error;
-	}
-
-	/* Create and start the read threads: */
-	for (index = 0; index < n_read_threads; ++index) {
-		read_thread_data[index].stop = 0;
-		read_thread_data[index].status = 0;
-		read_thread_data[index].epoll_set = epoll_set;
-		if (pthread_create(&read_threads[index],
-				   NULL,
-				   read_thread_function,
-				   &read_thread_data[index]) != 0)
-			goto error;
-	}
-
-	if (pthread_create(&write_thread,
-			   NULL,
-			   write_thread_function,
-			   &write_thread_data) != 0)
-		goto error;
-
-	/* Cancel all event pollers: */
-#ifdef EPOLL_CTL_DISABLE
-	for (index = 0; index < n_epoll_items; ++index) {
-		pthread_mutex_lock(&epoll_items[index].mutex);
-		++epoll_items[index].stop;
-		if (epoll_ctl(epoll_set,
-			      EPOLL_CTL_DISABLE,
-			      epoll_items[index].fd,
-			      NULL) == 0)
-			delete_item(index);
-		else if (errno != EBUSY) {
-			pthread_mutex_unlock(&epoll_items[index].mutex);
-			goto error;
-		}
-		/* EBUSY means events were being handled; allow the other thread
-		   to delete the item. */
-		pthread_mutex_unlock(&epoll_items[index].mutex);
-	}
-#else
-	for (index = 0; index < n_epoll_items; ++index) {
-		pthread_mutex_lock(&epoll_items[index].mutex);
-		++epoll_items[index].stop;
-		pthread_mutex_unlock(&epoll_items[index].mutex);
-		/* Wait in case a thread running read_thread_function is
-		   currently executing code between epoll_wait and
-		   pthread_mutex_lock with this item. Note that a longer delay
-		   would make double-deletion less likely (at the expense of
-		   performance), but there is no guarantee that any delay would
-		   ever be sufficient. Note also that we delete all event
-		   pollers at once for testing purposes, but in a real-world
-		   environment we are likely to want to be able to cancel event
-		   pollers at arbitrary times. Therefore we can't improve this
-		   situation by just splitting this loop into two loops
-		   (i.e. signal 'stop' for all items, sleep, and then delete all
-		   items). We also can't fix the problem via EPOLL_CTL_DEL
-		   because that command can't prevent the case where some other
-		   thread is executing read_thread_function within the region
-		   mentioned above: */
-		usleep(1);
-		pthread_mutex_lock(&epoll_items[index].mutex);
-		if (!epoll_items[index].deleted)
-			delete_item(index);
-		pthread_mutex_unlock(&epoll_items[index].mutex);
-	}
-#endif
-
-	/* Shut down the read threads: */
-	for (index = 0; index < n_read_threads; ++index)
-		__sync_fetch_and_add(&read_thread_data[index].stop, 1);
-	for (index = 0; index < n_read_threads; ++index) {
-		if (pthread_join(read_threads[index], NULL) != 0)
-			goto error;
-		if (read_thread_data[index].status)
-			goto error;
-	}
-
-	/* Shut down the write thread: */
-	__sync_fetch_and_add(&write_thread_data.stop, 1);
-	if ((pthread_join(write_thread, NULL) != 0) || write_thread_data.status)
-		goto error;
-
-	/* Check for final error conditions: */
-	for (index = 0; index < n_epoll_items; ++index) {
-		if (epoll_items[index].status != 0)
-			goto error;
-		if (pthread_mutex_destroy(&epoll_items[index].mutex) < 0)
-			goto error;
-	}
-	for (index = 0; index < n_epoll_items; ++index)
-		if (epoll_items[index].deleted != 1) {
-			printf("Error: item data deleted %1d times.\n",
-				   epoll_items[index].deleted);
-			goto error;
-		}
-
-	printf("[PASS]\n");
-	return 0;
-
- error:
-	printf("[FAIL]\n");
-	return errno;
-}
...	...	@@ -2,7 +2,8 @@
2	2	#define __ARCH_H8300_CACHE_H
3	3
4	4	/* bytes per L1 cache line */
5		-#define L1_CACHE_BYTES 4
	5	+#define L1_CACHE_SHIFT 2
	6	+#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
6	7
7	8	/* m68k-elf-gcc 2.95.2 doesn't like these */
8	9
...	...	@@ -346,7 +346,7 @@
346	346	/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */
347	347	static inline int ep_op_has_event(int op)
348	348	{
349		- return op == EPOLL_CTL_ADD \|\| op == EPOLL_CTL_MOD;
	349	+ return op != EPOLL_CTL_DEL;
350	350	}
351	351
352	352	/* Initialize the poll safe wake up structure */
...	...	@@ -676,34 +676,6 @@
676	676	return 0;
677	677	}
678	678
679		-/*
680		- * Disables a "struct epitem" in the eventpoll set. Returns -EBUSY if the item
681		- * had no event flags set, indicating that another thread may be currently
682		- * handling that item's events (in the case that EPOLLONESHOT was being
683		- * used). Otherwise a zero result indicates that the item has been disabled
684		- * from receiving events. A disabled item may be re-enabled via
685		- * EPOLL_CTL_MOD. Must be called with "mtx" held.
686		- */
687		-static int ep_disable(struct eventpoll ep, struct epitem epi)
688		-{
689		- int result = 0;
690		- unsigned long flags;
691		-
692		- spin_lock_irqsave(&ep->lock, flags);
693		- if (epi->event.events & ~EP_PRIVATE_BITS) {
694		- if (ep_is_linked(&epi->rdllink))
695		- list_del_init(&epi->rdllink);
696		- /* Ensure ep_poll_callback will not add epi back onto ready
697		- list: */
698		- epi->event.events &= EP_PRIVATE_BITS;
699		- }
700		- else
701		- result = -EBUSY;
702		- spin_unlock_irqrestore(&ep->lock, flags);
703		-
704		- return result;
705		-}
706		-
707	679	static void ep_free(struct eventpoll *ep)
708	680	{
709	681	struct rb_node *rbp;
...	...	@@ -1048,6 +1020,8 @@
1048	1020	rb_insert_color(&epi->rbn, &ep->rbr);
1049	1021	}
1050	1022
	1023	+
	1024	+
1051	1025	#define PATH_ARR_SIZE 5
1052	1026	/*
1053	1027	* These are the number paths of length 1 to 5, that we are allowing to emanate
...	...	@@ -1811,12 +1785,6 @@
1811	1785	epds.events \|= POLLERR \| POLLHUP;
1812	1786	error = ep_modify(ep, epi, &epds);
1813	1787	} else
1814		- error = -ENOENT;
1815		- break;
1816		- case EPOLL_CTL_DISABLE:
1817		- if (epi)
1818		- error = ep_disable(ep, epi);
1819		- else
1820	1788	error = -ENOENT;
1821	1789	break;
1822	1790	}
...	...	@@ -21,6 +21,7 @@
21	21	if ((old->path.mnt == new->path.mnt) &&
22	22	(old->path.dentry == new->path.dentry))
23	23	return true;
	24	+ break;
24	25	case (FSNOTIFY_EVENT_NONE):
25	26	return true;
26	27	default:
...	...	@@ -25,7 +25,6 @@
25	25	#define EPOLL_CTL_ADD 1
26	26	#define EPOLL_CTL_DEL 2
27	27	#define EPOLL_CTL_MOD 3
28		-#define EPOLL_CTL_DISABLE 4
29	28
30	29	/*
31	30	* Request the handling of system wakeup events so as to prevent system suspends
...	...	@@ -3017,6 +3017,8 @@
3017	3017	&balanced_classzone_idx);
3018	3018	}
3019	3019	}
	3020	+
	3021	+ current->reclaim_state = NULL;
3020	3022	return 0;
3021	3023	}
3022	3024
...	...	@@ -1890,8 +1890,10 @@
1890	1890	}
1891	1891
1892	1892	if ($realfile =~ m@^(drivers/net/\|net/)@ &&
1893		- $rawline !~ m@^\+[ \t](\/\\|\*\/)@ &&
1894		- $rawline =~ m@^\+[ \t].+\\/[ \t]*$@) {
	1893	+ $rawline !~ m@^\+[ \t]\/[ \t]$@ && #trailing /
	1894	+ $rawline !~ m@^\+./\.\/[ \t]$@ && #inline /...*/
	1895	+ $rawline !~ m@^\+.\{2,}/[ \t]$@ && #trailing */
	1896	+ $rawline =~ m@^\+[ \t].+\\/[ \t]$@) { #non blank /
1895	1897	WARN("NETWORKING_BLOCK_COMMENT_STYLE",
1896	1898	"networking block comments put the trailing */ on a separate line\n" . $herecurr);
1897	1899	}
1		-TARGETS = breakpoints kcmp mqueue vm cpu-hotplug memory-hotplug epoll
	1	+TARGETS = breakpoints kcmp mqueue vm cpu-hotplug memory-hotplug
2	2
3	3	all:
4	4	for TARGET in $(TARGETS); do \
1		-# Makefile for epoll selftests
2		-
3		-all: test_epoll
4		-%: %.c
5		- gcc -pthread -g -o $@ $^
6		-
7		-run_tests: all
8		- ./test_epoll
9		-
10		-clean:
11		- $(RM) test_epoll
1		-/*
2		- * tools/testing/selftests/epoll/test_epoll.c
3		- *
4		- * Copyright 2012 Adobe Systems Incorporated
5		- *
6		- * This program is free software; you can redistribute it and/or modify
7		- * it under the terms of the GNU General Public License as published by
8		- * the Free Software Foundation; either version 2 of the License, or
9		- * (at your option) any later version.
10		- *
11		- * Paton J. Lewis <palewis@adobe.com>
12		- *
13		- */
14		-
15		-#include <errno.h>
16		-#include <fcntl.h>
17		-#include <pthread.h>
18		-#include <stdio.h>
19		-#include <stdlib.h>
20		-#include <unistd.h>
21		-#include <sys/epoll.h>
22		-#include <sys/socket.h>
23		-
24		-/*
25		- * A pointer to an epoll_item_private structure will be stored in the epoll
26		- * item's event structure so that we can get access to the epoll_item_private
27		- * data after calling epoll_wait:
28		- */
29		-struct epoll_item_private {
30		- int index; /* Position of this struct within the epoll_items array. */
31		- int fd;
32		- uint32_t events;
33		- pthread_mutex_t mutex; /* Guards the following variables... */
34		- int stop;
35		- int status; /* Stores any error encountered while handling item. */
36		- /* The following variable allows us to test whether we have encountered
37		- a problem while attempting to cancel and delete the associated
38		- event. When the test program exits, 'deleted' should be exactly
39		- one. If it is greater than one, then the failed test reflects a real
40		- world situation where we would have tried to access the epoll item's
41		- private data after deleting it: */
42		- int deleted;
43		-};
44		-
45		-struct epoll_item_private *epoll_items;
46		-
47		-/*
48		- * Delete the specified item from the epoll set. In a real-world secneario this
49		- * is where we would free the associated data structure, but in this testing
50		- * environment we retain the structure so that we can test for double-deletion:
51		- */
52		-void delete_item(int index)
53		-{
54		- __sync_fetch_and_add(&epoll_items[index].deleted, 1);
55		-}
56		-
57		-/*
58		- * A pointer to a read_thread_data structure will be passed as the argument to
59		- * each read thread:
60		- */
61		-struct read_thread_data {
62		- int stop;
63		- int status; /* Indicates any error encountered by the read thread. */
64		- int epoll_set;
65		-};
66		-
67		-/*
68		- * The function executed by the read threads:
69		- */
70		-void read_thread_function(void function_data)
71		-{
72		- struct read_thread_data *thread_data =
73		- (struct read_thread_data *)function_data;
74		- struct epoll_event event_data;
75		- struct epoll_item_private *item_data;
76		- char socket_data;
77		-
78		- /* Handle events until we encounter an error or this thread's 'stop'
79		- condition is set: */
80		- while (1) {
81		- int result = epoll_wait(thread_data->epoll_set,
82		- &event_data,
83		- 1, /* Number of desired events */
84		- 1000); /* Timeout in ms */
85		- if (result < 0) {
86		- /* Breakpoints signal all threads. Ignore that while
87		- debugging: */
88		- if (errno == EINTR)
89		- continue;
90		- thread_data->status = errno;
91		- return 0;
92		- } else if (thread_data->stop)
93		- return 0;
94		- else if (result == 0) /* Timeout */
95		- continue;
96		-
97		- /* We need the mutex here because checking for the stop
98		- condition and re-enabling the epoll item need to be done
99		- together as one atomic operation when EPOLL_CTL_DISABLE is
100		- available: */
101		- item_data = (struct epoll_item_private *)event_data.data.ptr;
102		- pthread_mutex_lock(&item_data->mutex);
103		-
104		- /* Remove the item from the epoll set if we want to stop
105		- handling that event: */
106		- if (item_data->stop)
107		- delete_item(item_data->index);
108		- else {
109		- /* Clear the data that was written to the other end of
110		- our non-blocking socket: */
111		- do {
112		- if (read(item_data->fd, &socket_data, 1) < 1) {
113		- if ((errno == EAGAIN) \|\|
114		- (errno == EWOULDBLOCK))
115		- break;
116		- else
117		- goto error_unlock;
118		- }
119		- } while (item_data->events & EPOLLET);
120		-
121		- /* The item was one-shot, so re-enable it: */
122		- event_data.events = item_data->events;
123		- if (epoll_ctl(thread_data->epoll_set,
124		- EPOLL_CTL_MOD,
125		- item_data->fd,
126		- &event_data) < 0)
127		- goto error_unlock;
128		- }
129		-
130		- pthread_mutex_unlock(&item_data->mutex);
131		- }
132		-
133		-error_unlock:
134		- thread_data->status = item_data->status = errno;
135		- pthread_mutex_unlock(&item_data->mutex);
136		- return 0;
137		-}
138		-
139		-/*
140		- * A pointer to a write_thread_data structure will be passed as the argument to
141		- * the write thread:
142		- */
143		-struct write_thread_data {
144		- int stop;
145		- int status; /* Indicates any error encountered by the write thread. */
146		- int n_fds;
147		- int *fds;
148		-};
149		-
150		-/*
151		- * The function executed by the write thread. It writes a single byte to each
152		- * socket in turn until the stop condition for this thread is set. If writing to
153		- * a socket would block (i.e. errno was EAGAIN), we leave that socket alone for
154		- * the moment and just move on to the next socket in the list. We don't care
155		- * about the order in which we deliver events to the epoll set. In fact we don't
156		- * care about the data we're writing to the pipes at all; we just want to
157		- * trigger epoll events:
158		- */
159		-void write_thread_function(void function_data)
160		-{
161		- const char data = 'X';
162		- int index;
163		- struct write_thread_data *thread_data =
164		- (struct write_thread_data *)function_data;
165		- while (!thread_data->stop)
166		- for (index = 0;
167		- !thread_data->stop && (index < thread_data->n_fds);
168		- ++index)
169		- if ((write(thread_data->fds[index], &data, 1) < 1) &&
170		- (errno != EAGAIN) &&
171		- (errno != EWOULDBLOCK)) {
172		- thread_data->status = errno;
173		- return;
174		- }
175		-}
176		-
177		-/*
178		- * Arguments are currently ignored:
179		- */
180		-int main(int argc, char **argv)
181		-{
182		- const int n_read_threads = 100;
183		- const int n_epoll_items = 500;
184		- int index;
185		- int epoll_set = epoll_create1(0);
186		- struct write_thread_data write_thread_data = {
187		- 0, 0, n_epoll_items, malloc(n_epoll_items * sizeof(int))
188		- };
189		- struct read_thread_data *read_thread_data =
190		- malloc(n_read_threads * sizeof(struct read_thread_data));
191		- pthread_t read_threads = malloc(n_read_threads sizeof(pthread_t));
192		- pthread_t write_thread;
193		-
194		- printf("-----------------\n");
195		- printf("Runing test_epoll\n");
196		- printf("-----------------\n");
197		-
198		- epoll_items = malloc(n_epoll_items * sizeof(struct epoll_item_private));
199		-
200		- if (epoll_set < 0 \|\| epoll_items == 0 \|\| write_thread_data.fds == 0 \|\|
201		- read_thread_data == 0 \|\| read_threads == 0)
202		- goto error;
203		-
204		- if (sysconf(_SC_NPROCESSORS_ONLN) < 2) {
205		- printf("Error: please run this test on a multi-core system.\n");
206		- goto error;
207		- }
208		-
209		- /* Create the socket pairs and epoll items: */
210		- for (index = 0; index < n_epoll_items; ++index) {
211		- int socket_pair[2];
212		- struct epoll_event event_data;
213		- if (socketpair(AF_UNIX,
214		- SOCK_STREAM \| SOCK_NONBLOCK,
215		- 0,
216		- socket_pair) < 0)
217		- goto error;
218		- write_thread_data.fds[index] = socket_pair[0];
219		- epoll_items[index].index = index;
220		- epoll_items[index].fd = socket_pair[1];
221		- if (pthread_mutex_init(&epoll_items[index].mutex, NULL) != 0)
222		- goto error;
223		- /* We always use EPOLLONESHOT because this test is currently
224		- structured to demonstrate the need for EPOLL_CTL_DISABLE,
225		- which only produces useful information in the EPOLLONESHOT
226		- case (without EPOLLONESHOT, calling epoll_ctl with
227		- EPOLL_CTL_DISABLE will never return EBUSY). If support for
228		- testing events without EPOLLONESHOT is desired, it should
229		- probably be implemented in a separate unit test. */
230		- epoll_items[index].events = EPOLLIN \| EPOLLONESHOT;
231		- if (index < n_epoll_items / 2)
232		- epoll_items[index].events \|= EPOLLET;
233		- epoll_items[index].stop = 0;
234		- epoll_items[index].status = 0;
235		- epoll_items[index].deleted = 0;
236		- event_data.events = epoll_items[index].events;
237		- event_data.data.ptr = &epoll_items[index];
238		- if (epoll_ctl(epoll_set,
239		- EPOLL_CTL_ADD,
240		- epoll_items[index].fd,
241		- &event_data) < 0)
242		- goto error;
243		- }
244		-
245		- /* Create and start the read threads: */
246		- for (index = 0; index < n_read_threads; ++index) {
247		- read_thread_data[index].stop = 0;
248		- read_thread_data[index].status = 0;
249		- read_thread_data[index].epoll_set = epoll_set;
250		- if (pthread_create(&read_threads[index],
251		- NULL,
252		- read_thread_function,
253		- &read_thread_data[index]) != 0)
254		- goto error;
255		- }
256		-
257		- if (pthread_create(&write_thread,
258		- NULL,
259		- write_thread_function,
260		- &write_thread_data) != 0)
261		- goto error;
262		-
263		- /* Cancel all event pollers: */
264		-#ifdef EPOLL_CTL_DISABLE
265		- for (index = 0; index < n_epoll_items; ++index) {
266		- pthread_mutex_lock(&epoll_items[index].mutex);
267		- ++epoll_items[index].stop;
268		- if (epoll_ctl(epoll_set,
269		- EPOLL_CTL_DISABLE,
270		- epoll_items[index].fd,
271		- NULL) == 0)
272		- delete_item(index);
273		- else if (errno != EBUSY) {
274		- pthread_mutex_unlock(&epoll_items[index].mutex);
275		- goto error;
276		- }
277		- /* EBUSY means events were being handled; allow the other thread
278		- to delete the item. */
279		- pthread_mutex_unlock(&epoll_items[index].mutex);
280		- }
281		-#else
282		- for (index = 0; index < n_epoll_items; ++index) {
283		- pthread_mutex_lock(&epoll_items[index].mutex);
284		- ++epoll_items[index].stop;
285		- pthread_mutex_unlock(&epoll_items[index].mutex);
286		- /* Wait in case a thread running read_thread_function is
287		- currently executing code between epoll_wait and
288		- pthread_mutex_lock with this item. Note that a longer delay
289		- would make double-deletion less likely (at the expense of
290		- performance), but there is no guarantee that any delay would
291		- ever be sufficient. Note also that we delete all event
292		- pollers at once for testing purposes, but in a real-world
293		- environment we are likely to want to be able to cancel event
294		- pollers at arbitrary times. Therefore we can't improve this
295		- situation by just splitting this loop into two loops
296		- (i.e. signal 'stop' for all items, sleep, and then delete all
297		- items). We also can't fix the problem via EPOLL_CTL_DEL
298		- because that command can't prevent the case where some other
299		- thread is executing read_thread_function within the region
300		- mentioned above: */
301		- usleep(1);
302		- pthread_mutex_lock(&epoll_items[index].mutex);
303		- if (!epoll_items[index].deleted)
304		- delete_item(index);
305		- pthread_mutex_unlock(&epoll_items[index].mutex);
306		- }
307		-#endif
308		-
309		- /* Shut down the read threads: */
310		- for (index = 0; index < n_read_threads; ++index)
311		- __sync_fetch_and_add(&read_thread_data[index].stop, 1);
312		- for (index = 0; index < n_read_threads; ++index) {
313		- if (pthread_join(read_threads[index], NULL) != 0)
314		- goto error;
315		- if (read_thread_data[index].status)
316		- goto error;
317		- }
318		-
319		- /* Shut down the write thread: */
320		- __sync_fetch_and_add(&write_thread_data.stop, 1);
321		- if ((pthread_join(write_thread, NULL) != 0) \|\| write_thread_data.status)
322		- goto error;
323		-
324		- /* Check for final error conditions: */
325		- for (index = 0; index < n_epoll_items; ++index) {
326		- if (epoll_items[index].status != 0)
327		- goto error;
328		- if (pthread_mutex_destroy(&epoll_items[index].mutex) < 0)
329		- goto error;
330		- }
331		- for (index = 0; index < n_epoll_items; ++index)
332		- if (epoll_items[index].deleted != 1) {
333		- printf("Error: item data deleted %1d times.\n",
334		- epoll_items[index].deleted);
335		- goto error;
336		- }
337		-
338		- printf("[PASS]\n");
339		- return 0;
340		-
341		- error:
342		- printf("[FAIL]\n");
343		- return errno;
344		-}