From: David Howells <dhowells@redhat.com>
Date: Fri, 6 Dec 2019 21:34:51 +0000 (+0000)
Subject: pipe: Fix iteration end check in fuse_dev_splice_write()
X-Git-Tag: microblaze-v5.6-rc1~30
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=76f6777c9cc04efe8036b1d2aa76e618c1631cc6;hp=43a2898631a8beee66c1d64c1e860f43d96b2e91;p=linux-2.6-microblaze.git

pipe: Fix iteration end check in fuse_dev_splice_write()

Fix the iteration end check in fuse_dev_splice_write().  The iterator
position can only be compared with == or != since wrappage may be involved.

Fixes: 8cefc107ca54 ("pipe: Use head and tail pointers for the ring, not cursor and length")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index d4e6691d2d92..8e02d76fe104 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1965,7 +1965,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 
 	nbuf = 0;
 	rem = 0;
-	for (idx = tail; idx < head && rem < len; idx++)
+	for (idx = tail; idx != head && rem < len; idx++)
 		rem += pipe->bufs[idx & mask].len;
 
 	ret = -EINVAL;