From 9567366fefddeaea4ed1d713270535d93a3b3c76 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 12 Apr 2016 12:14:46 -0400 Subject: [PATCH] dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros 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") Cc: stable@vger.kernel.org --- 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 27f2ef300f8b..65ce6985f87a 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -867,39 +867,55 @@ 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) { -- 2.11.0