From: jon ernst Subject: [PATCH] ext4: silence sparse check warning for function ext4_trim_extent. Date: Sat, 12 Apr 2014 22:25:45 -0400 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: "linux-ext4@vger.kernel.org List" , "Theodore Ts'o" Return-path: Received: from mail-qa0-f46.google.com ([209.85.216.46]:55485 "EHLO mail-qa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750876AbaDMCcE (ORCPT ); Sat, 12 Apr 2014 22:32:04 -0400 Received: by mail-qa0-f46.google.com with SMTP id i13so6724286qae.19 for ; Sat, 12 Apr 2014 19:32:02 -0700 (PDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: By doing "make M=fs/ext4 C=2" on commit ad6599ab3ac98a4474544086e048ce86ec15a4d1 sparse reports this warning: CHECK fs/ext4/mballoc.c fs/ext4/mballoc.c:5019:9: warning: context imbalance in 'ext4_trim_extent' - unexpected unlock >From Documentation/sparse.txt: Using sparse for lock checking ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The following macros are undefined for gcc and defined during a sparse run to use the "context" tracking feature of sparse, applied to locking. These annotations tell sparse when a lock is held, with regard to the annotated function's entry and exit. __must_hold - The specified lock is held on function entry and exit. __acquires - The specified lock is held on function exit, but not entry. __releases - The specified lock is held on function entry, but not exit. If the function enters and exits without the lock held, acquiring and releasing the lock inside the function in a balanced way, no annotation is needed. The tree annotations above are for cases where sparse would otherwise report a context imbalance. Signed-off-by: "Jon Ernst" --- fs/ext4/mballoc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 73ccbb3..c8238a2 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -5016,6 +5016,8 @@ error_return: */ static int ext4_trim_extent(struct super_block *sb, int start, int count, ext4_group_t group, struct ext4_buddy *e4b) +__releases(bitlock) +__acquires(bitlock) { struct ext4_free_extent ex; int ret = 0; -- 1.8.1.2