[PATCH 3.18 19/47] dm bufio: hide bogus warning

Greg Kroah-Hartman
2017-04-28T08:38:29Z

From: Arnd Bergmann <arnd@arndb.de>

mips-gcc-5.3 warns about correct code on linux-3.18 and earlier:

In file included from ../include/linux/blkdev.h:4:0,
from ../drivers/md/dm-bufio.h:12,
from ../drivers/md/dm-bufio.c:9:
../drivers/md/dm-bufio.c: In function 'alloc_buffer':
../include/linux/sched.h:1975:56: warning: 'noio_flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
../drivers/md/dm-bufio.c:325:11: note: 'noio_flag' was declared here

The warning disappeared on later kernels with this commit: be0c37c985ed
("MIPS: Rearrange PTE bits into fixed positions.") I assume this only
happened because it changed some inlining decisions.

On 3.18.y, we can shut up the warning by adding an extra initialization.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/md/dm-bufio.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -349,6 +349,7 @@ static void *alloc_buffer_data(struct dm
* as if GFP_NOIO was specified.
*/

+ noio_flag = 0;
if (gfp_mask & __GFP_NORETRY)
noio_flag = memalloc_noio_save();