epoll: Don't limit non-nested epoll paths

svn path=/dists/sid/linux-2.6/; revision=18859

debian/changelog

@@ -20,6 +20,7 @@ linux-2.6 (3.2.12-1) UNRELEASED; urgency=low
   * [s390] Ignore arch_pick_mmap_layout version change; it should not be
     needed by modules (fixes FTBFS)
   * [x86] Disable POHMELFS; this version is obsolete
+  * epoll: Don't limit non-nested epoll paths
 
   [ Jonathan Nieder ]
   * [x86] Enable RTS5139 as module (Closes: #663912)

debian/patches/bugfix/all/Don-t-limit-non-nested-epoll-paths.patch

@@ -0,0 +1,42 @@
+From: Jason Baron <jbaron@redhat.com>
+Date: Fri, 16 Mar 2012 16:34:03 -0400
+Subject: [PATCH] Don't limit non-nested epoll paths
+
+commit 93dc6107a76daed81c07f50215fa6ae77691634f upstream.
+
+Commit 28d82dc1c4ed ("epoll: limit paths") that I did to limit the
+number of possible wakeup paths in epoll is causing a few applications
+to longer work (dovecot for one).
+
+The original patch is really about limiting the amount of epoll nesting
+(since epoll fds can be attached to other fds). Thus, we probably can
+allow an unlimited number of paths of depth 1. My current patch limits
+it at 1000. And enforce the limits on paths that have a greater depth.
+
+This is captured in: https://bugzilla.redhat.com/show_bug.cgi?id=681578
+
+Signed-off-by: Jason Baron <jbaron@redhat.com>
+Cc: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+---
+ fs/eventpoll.c |    4 ++++
+ 1 files changed, 4 insertions(+), 0 deletions(-)
+
+diff --git a/fs/eventpoll.c b/fs/eventpoll.c
+index ea54cde..4d9d3a4 100644
+--- a/fs/eventpoll.c
++++ b/fs/eventpoll.c
+@@ -988,6 +988,10 @@ 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;
+-- 
+1.7.9.1
+

debian/patches/series/base

@@ -81,3 +81,4 @@
 + features/all/fs-hardlink-creation-restrictions.patch
 + features/all/fs-hardlink-creation-restrictions-fix.patch
 + features/all/fs-hardlink-creation-restriction-cleanup.patch
++ bugfix/all/Don-t-limit-non-nested-epoll-paths.patch