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authorArnd Bergmann <arnd@arndb.de>2018-02-22 16:56:16 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-06-13 16:16:44 +0200
commite1fba17e26f08a142b4cdf5c74a2113e7f895daa (patch)
treef44dd817bb9968f282635c7c09d969237669c588
parent02136f325f84b5dbd5cab556daae15b25948c774 (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.c17
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);
}
/*