tree e1faec166f3edb5974829d9f7ec4c25e02fd1572
parent ef9a61bef917e38f8e096f6df303329aed6cf467
author Olof Johansson <olof@lixom.net> 1378748063 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1378748862 -0700

direct-io: Use return from cmpxchg to decide of assignment happened

Not using the return value can in the generic case be racy, so it's
in general good practice to check the return value instead.

This also resolved the warning caused on ARM and other architectures:

  fs/direct-io.c: In function 'sb_init_dio_done_wq':
  fs/direct-io.c:557:2: warning: value computed is not used [-Wunused-value]

Signed-off-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: H Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>