Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 44 insertions, 6 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index ea54cdef04d..739b0985b39 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -34,7 +34,6 @@
 #include <linux/mutex.h>
 #include <linux/anon_inodes.h>
 #include <asm/uaccess.h>
-#include <asm/system.h>
 #include <asm/io.h>
 #include <asm/mman.h>
 #include <linux/atomic.h>
@@ -427,6 +426,31 @@ out_unlock:
 	return error;
 }
 
+/*
+ * 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.
+ */
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 static inline void ep_wake_up_nested(wait_queue_head_t *wqueue,
 				     unsigned long events, int subclass)
@@ -699,9 +723,12 @@ static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
 			       void *priv)
 {
 	struct epitem *epi, *tmp;
+	poll_table pt;
 
+	init_poll_funcptr(&pt, NULL);
 	list_for_each_entry_safe(epi, tmp, head, rdllink) {
-		if (epi->ffd.file->f_op->poll(epi->ffd.file, NULL) &
+		pt._key = epi->event.events;
+		if (epi->ffd.file->f_op->poll(epi->ffd.file, &pt) &
 		    epi->event.events)
 			return POLLIN | POLLRDNORM;
 		else {
@@ -988,6 +1015,10 @@ static int path_count[PATH_ARR_SIZE];
 
 static int path_count_inc(int nests)
 {
+	/* Allow an arbitrary number of depth 1 paths */
+	if (nests == 0)
+		return 0;
+
 	if (++path_count[nests] > path_limits[nests])
 		return -1;
 	return 0;
@@ -1045,13 +1076,11 @@ static int reverse_path_check_proc(void *priv, void *cookie, int call_nests)
  */
 static int reverse_path_check(void)
 {
-	int length = 0;
 	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) {
-		length++;
 		path_count_init();
 		error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS,
 					reverse_path_check_proc, current_file,
@@ -1093,6 +1122,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 	/* Initialize the poll table using the queue callback */
 	epq.epi = epi;
 	init_poll_funcptr(&epq.pt, ep_ptable_queue_proc);
+	epq.pt._key = event->events;
 
 	/*
 	 * Attach the item to the poll hooks and get current event bits.
@@ -1187,6 +1217,9 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even
 {
 	int pwake = 0;
 	unsigned int revents;
+	poll_table pt;
+
+	init_poll_funcptr(&pt, NULL);
 
 	/*
 	 * Set the new event interest mask before calling f_op->poll();
@@ -1194,13 +1227,14 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even
 	 * f_op->poll() call and the new event set registering.
 	 */
 	epi->event.events = event->events;
+	pt._key = event->events;
 	epi->event.data = event->data; /* protected by mtx */
 
 	/*
 	 * Get current event bits. We can safely use the file* here because
 	 * its usage count has been increased by the caller of this function.
 	 */
-	revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL);
+	revents = epi->ffd.file->f_op->poll(epi->ffd.file, &pt);
 
 	/*
 	 * If the item is "hot" and it is not registered inside the ready
@@ -1235,6 +1269,9 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
 	unsigned int revents;
 	struct epitem *epi;
 	struct epoll_event __user *uevent;
+	poll_table pt;
+
+	init_poll_funcptr(&pt, NULL);
 
 	/*
 	 * We can loop without lock because we are passed a task private list.
@@ -1247,7 +1284,8 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
 
 		list_del_init(&epi->rdllink);
 
-		revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL) &
+		pt._key = epi->event.events;
+		revents = epi->ffd.file->f_op->poll(epi->ffd.file, &pt) &
 			epi->event.events;
 
 		/*