Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753494AbcDZScp (ORCPT ); Tue, 26 Apr 2016 14:32:45 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56443 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752948AbcDZSSs (ORCPT ); Tue, 26 Apr 2016 14:18:48 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Mike Snitzer , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 53/93] dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros Date: Tue, 26 Apr 2016 11:16:53 -0700 Message-Id: <1461694653-29506-54-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1461694653-29506-1-git-send-email-kamal@canonical.com> References: <1461694653-29506-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3231 Lines: 114 4.2.8-ckt9 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Mike Snitzer commit 9567366fefddeaea4ed1d713270535d93a3b3c76 upstream. The READ_LOCK macro was incorrectly returning -EINVAL if dm_bm_is_read_only() was true -- it will always be true once the cache metadata transitions to read-only by dm_cache_metadata_set_read_only(). Wrap READ_LOCK and WRITE_LOCK multi-statement macros in do {} while(0). Also, all accesses of the 'cmd' argument passed to these related macros are now encapsulated in parenthesis. A follow-up patch can be developed to eliminate the use of macros in favor of pure C code. Avoiding that now given that this needs to apply to stable@. Reported-by: Ben Hutchings Signed-off-by: Mike Snitzer Fixes: d14fcf3dd79 ("dm cache: make sure every metadata function checks fail_io") Signed-off-by: Kamal Mostafa --- drivers/md/dm-cache-metadata.c | 64 ++++++++++++++++++++++++++---------------- 1 file changed, 40 insertions(+), 24 deletions(-) diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index 1ed4ab1..141b9bc 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -863,39 +863,55 @@ static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, return 0; } -#define WRITE_LOCK(cmd) \ - down_write(&cmd->root_lock); \ - if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ - up_write(&cmd->root_lock); \ - return -EINVAL; \ +static bool cmd_write_lock(struct dm_cache_metadata *cmd) +{ + down_write(&cmd->root_lock); + if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { + up_write(&cmd->root_lock); + return false; } + return true; +} -#define WRITE_LOCK_VOID(cmd) \ - down_write(&cmd->root_lock); \ - if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ - up_write(&cmd->root_lock); \ - return; \ - } +#define WRITE_LOCK(cmd) \ + do { \ + if (!cmd_write_lock((cmd))) \ + return -EINVAL; \ + } while(0) + +#define WRITE_LOCK_VOID(cmd) \ + do { \ + if (!cmd_write_lock((cmd))) \ + return; \ + } while(0) #define WRITE_UNLOCK(cmd) \ - up_write(&cmd->root_lock) + up_write(&(cmd)->root_lock) -#define READ_LOCK(cmd) \ - down_read(&cmd->root_lock); \ - if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ - up_read(&cmd->root_lock); \ - return -EINVAL; \ +static bool cmd_read_lock(struct dm_cache_metadata *cmd) +{ + down_write(&cmd->root_lock); + if (cmd->fail_io) { + up_write(&cmd->root_lock); + return false; } + return true; +} -#define READ_LOCK_VOID(cmd) \ - down_read(&cmd->root_lock); \ - if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ - up_read(&cmd->root_lock); \ - return; \ - } +#define READ_LOCK(cmd) \ + do { \ + if (!cmd_read_lock((cmd))) \ + return -EINVAL; \ + } while(0) + +#define READ_LOCK_VOID(cmd) \ + do { \ + if (!cmd_read_lock((cmd))) \ + return; \ + } while(0) #define READ_UNLOCK(cmd) \ - up_read(&cmd->root_lock) + up_read(&(cmd)->root_lock) int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) { -- 2.7.4