Kernel/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-01-17 02:15:57 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

scsi: sd_zbc: Use kvzalloc() to allocate REPORT ZONES buffer

Browse Source 
We have two reports of failed memory allocation in btrfs' code which is
calling into report zones.

Both of these reports have the following signature coming from
__vmalloc_area_node():

 kworker/u17:5: vmalloc error: size 0, failed to allocate pages, mode:0x10dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NORETRY|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0

Further debugging showed these where allocations of one sector (512
bytes) and at least one of the reporter's systems where low on memory,
so going through the overhead of allocating a vm area failed.

Switching the allocation from __vmalloc() to kvzalloc() avoids the
overhead of vmalloc() on small allocations and succeeds.

Note: the buffer is already freed using kvfree() so there's no need to
adjust the free path.

Cc: Qu Wenru <wqu@suse.com>
Cc: Naohiro Aota <naohiro.aota@wdc.com>
Link: https://github.com/kdave/btrfs-progs/issues/779
Link: https://github.com/kdave/btrfs-progs/issues/915
Fixes: 23a50861adda ("scsi: sd_zbc: Cleanup sd_zbc_alloc_report_buffer()")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241030110253.11718-1-jth@kernel.org
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Johannes Thumshirn 2024-10-30 12:02:53 +01:00 committed by Martin K. Petersen
parent cb7e509c4e
commit 7ce3e61071
1 changed files with 1 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/scsi/sd_zbc.c
View File

@ -188,8 +188,7 @@ static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
while (bufsize >= SECTOR_SIZE) {
buf = __vmalloc(bufsize,
GFP_KERNEL | __GFP_ZERO | __GFP_NORETRY);
buf = kvzalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
if (buf) {
*buflen = bufsize;
return buf;