mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-11 02:59:12 +00:00
Code Issues Releases Wiki Activity

bcache: avoid clang -Wunintialized warning

Browse source 
[ Upstream commit 78d4eb8ad9 ]

clang has identified a code path in which it thinks a
variable may be unused:

drivers/md/bcache/alloc.c:333:4: error: variable 'bucket' is used uninitialized whenever 'if' condition is false
      [-Werror,-Wsometimes-uninitialized]
                        fifo_pop(&ca->free_inc, bucket);
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/md/bcache/util.h:219:27: note: expanded from macro 'fifo_pop'
 #define fifo_pop(fifo, i)       fifo_pop_front(fifo, (i))
                                ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/md/bcache/util.h:189:6: note: expanded from macro 'fifo_pop_front'
        if (_r) {                                                       \
            ^~
drivers/md/bcache/alloc.c:343:46: note: uninitialized use occurs here
                        allocator_wait(ca, bch_allocator_push(ca, bucket));
                                                                  ^~~~~~
drivers/md/bcache/alloc.c:287:7: note: expanded from macro 'allocator_wait'
                if (cond)                                               \
                    ^~~~
drivers/md/bcache/alloc.c:333:4: note: remove the 'if' if its condition is always true
                        fifo_pop(&ca->free_inc, bucket);
                        ^
drivers/md/bcache/util.h:219:27: note: expanded from macro 'fifo_pop'
 #define fifo_pop(fifo, i)       fifo_pop_front(fifo, (i))
                                ^
drivers/md/bcache/util.h:189:2: note: expanded from macro 'fifo_pop_front'
        if (_r) {                                                       \
        ^
drivers/md/bcache/alloc.c:331:15: note: initialize the variable 'bucket' to silence this warning
                        long bucket;
                                   ^

This cannot happen in practice because we only enter the loop
if there is at least one element in the list.

Slightly rearranging the code makes this clearer to both the
reader and the compiler, which avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Arnd Bergmann 2019-04-25 00:48:28 +08:00 committed by Greg Kroah-Hartman
parent 330b679803
commit 06740892db
1 changed files with 3 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/md/bcache/alloc.c
View file

@ -327,10 +327,11 @@ static int bch_allocator_thread(void *arg)
* possibly issue discards to them, then we add the bucket to
* the free list:
*/
while (!fifo_empty(&ca->free_inc)) {
while (1) {
long bucket;
fifo_pop(&ca->free_inc, bucket);
if (!fifo_pop(&ca->free_inc, bucket))
break;
if (ca->discard) {
mutex_unlock(&ca->set->bucket_lock);