diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2018-02-22 16:56:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-06-13 16:16:44 +0200 |
| commit | e1fba17e26f08a142b4cdf5c74a2113e7f895daa (patch) | |
| tree | f44dd817bb9968f282635c7c09d969237669c588 | |
| parent | 02136f325f84b5dbd5cab556daae15b25948c774 (diff) | |
dm bufio: avoid false-positive Wmaybe-uninitialized warning
commit 590347e4000356f55eb10b03ced2686bd74dab40 upstream.
gcc-6.3 and earlier show a new warning after a seemingly unrelated
change to the arm64 PAGE_KERNEL definition:
In file included from drivers/md/dm-bufio.c:14:0:
drivers/md/dm-bufio.c: In function 'alloc_buffer':
include/linux/sched/mm.h:182:56: warning: 'noio_flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
^
The same warning happened earlier on linux-3.18 for MIPS and I did a
workaround for that, but now it's come back.
gcc-7 and newer are apparently smart enough to figure this out, and
other architectures don't show it, so the best I could come up with is
to rework the caller slightly in a way that makes it obvious enough to
all arm64 compilers what is happening here.
Fixes: 41acec624087 ("arm64: kpti: Make use of nG dependent on arm64_kernel_unmapped_at_el0()")
Link: https://patchwork.kernel.org/patch/9692829/
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[snitzer: moved declarations inside conditional, altered vmalloc return]
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
[nc: Backport to 4.9, adjust context for lack of 19809c2da28a]
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/dm-bufio.c | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 3ec647e8b9c6..35fd57fdeba9 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -373,9 +373,6 @@ static void __cache_size_refresh(void) static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, enum data_mode *data_mode) { - unsigned noio_flag; - void *ptr; - if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { *data_mode = DATA_MODE_SLAB; return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); @@ -399,16 +396,16 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, * all allocations done by this process (including pagetables) are done * as if GFP_NOIO was specified. */ + if (gfp_mask & __GFP_NORETRY) { + unsigned noio_flag = memalloc_noio_save(); + void *ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, + PAGE_KERNEL); - if (gfp_mask & __GFP_NORETRY) - noio_flag = memalloc_noio_save(); - - ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); - - if (gfp_mask & __GFP_NORETRY) memalloc_noio_restore(noio_flag); + return ptr; + } - return ptr; + return __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); } /* |