From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: [PATCH] dm-bufio: avoid false-positive Wmaybe-uninitialized warning Date: Thu, 22 Feb 2018 16:56:16 +0100 Message-ID: <20180222155627.1800948-1-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com Cc: Jens Axboe , Mark Rutland , Jan Kara , Arnd Bergmann , Eric Biggers , linux-kernel@vger.kernel.org, Aliaksei Karaliou , Mikulas Patocka , Ingo Molnar , Dan Carpenter List-Id: dm-devel.ids 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/ Signed-off-by: Arnd Bergmann --- drivers/md/dm-bufio.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 414c9af54ded..e7ad6fc6a5ea 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -413,13 +413,13 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, * as if GFP_NOIO was specified. */ - if (gfp_mask & __GFP_NORETRY) + if (gfp_mask & __GFP_NORETRY) { noio_flag = memalloc_noio_save(); - - ptr = __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL); - - if (gfp_mask & __GFP_NORETRY) + ptr = __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL); memalloc_noio_restore(noio_flag); + } else { + ptr = __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL); + } return ptr; } -- 2.9.0