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author | Jianchao Wang <jianchao.w.wang@oracle.com> | 2018-10-12 18:07:28 +0800 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-10-13 15:42:04 -0600 |
commit | e01ad46d53b59720c6ae69963ee1756506954c85 (patch) | |
tree | d84fbc92eacf1b2341032ae25dd93a3dc3dd1a3d /drivers/block | |
parent | 34d11ffac1f56c3895dad32153abd6814452dc77 (diff) |
blk-mq: fallback to previous nr_hw_queues when updating fails
When we try to increate the nr_hw_queues, we may fail due to
shortage of memory or other reason, then blk_mq_realloc_hw_ctxs stops
and some entries in q->queue_hw_ctx are left with NULL. However,
because queue map has been updated with new nr_hw_queues, some cpus
have been mapped to hw queue which just encounters allocation failure,
thus blk_mq_map_queue could return NULL. This will cause panic in
following blk_mq_map_swqueue.
To fix it, when increase nr_hw_queues fails, fallback to previous
nr_hw_queues and post warning. At the same time, driver's .map_queues
usually use completion irq affinity to map hw and cpu, fallback
nr_hw_queues will cause lack of some cpu's map to hw, so use default
blk_mq_map_queues to do that.
Reported-by: syzbot+83e8cbe702263932d9d4@syzkaller.appspotmail.com
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
0 files changed, 0 insertions, 0 deletions