Patch "gfs2: avoid uninitialized variable warning" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

gfs2: avoid uninitialized variable warning

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
gfs2-avoid-uninitialized-variable-warning.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Arnd Bergmann <[email protected]>
Date: Tue, 26 Jan 2016 13:08:10 -0500
Subject: gfs2: avoid uninitialized variable warning

From: Arnd Bergmann <[email protected]>

commit 67893f12e5374bbcaaffbc6e570acbc2714ea884 upstream.

We get a bogus warning about a potential uninitialized variable use in gfs2, because the compiler does not figure out that we never use the leaf number if get_leaf_nr() returns an error:

fs/gfs2/dir.c: In function 'get_first_leaf':
fs/gfs2/dir.c:802:9: warning: 'leaf_no' may be used uninitialized in this function [-Wmaybe-uninitialized] fs/gfs2/dir.c: In function 'dir_split_leaf':
fs/gfs2/dir.c:1021:8: warning: 'leaf_no' may be used uninitialized in this function [-Wmaybe-uninitialized]

Changing the 'if (!error)' to 'if (!IS_ERR_VALUE(error))' is sufficient to let gcc understand that this is exactly the same condition as in IS_ERR() so it can optimize the code path enough to understand it.

---
 fs/gfs2/dir.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -760,7 +760,7 @@ static int get_first_leaf(struct gfs2_in
 	int error;
 
 	error = get_leaf_nr(dip, index, &leaf_no);
-	if (!error)
+	if (!IS_ERR_VALUE(error))
 		error = get_leaf(dip, leaf_no, bh_out);
 
 	return error;

@@ -976,7 +976,7 @@ static int dir_split_leaf(struct inode *
 
 	index = name->hash >> (32 - dip->i_depth);
 	error = get_leaf_nr(dip, index, &leaf_no);
-	if (error)
+	if (IS_ERR_VALUE(error))
 		return error;
 
 	/*  Get the old leaf block  */

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/tty-nozomi-avoid-a-harmless-gcc-warning.patch queue-4.4/gfs2-avoid-uninitialized-variable-warning.patch queue-4.4/hostap-avoid-uninitialized-variable-use-in-hfa384x_get_rid.patch