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| author |   Ming Lei <ming.lei@redhat.com> | 2019-04-30 09:52:27 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2019-05-04 07:24:08 -0600 |
| commit | 2f8f1336a48bd5186de3476da0a3e2ec06d0533a (patch) | |
| tree | 1bc1ee8510442e16f00ba1cf82ebfb0dfb926017 /include/linux/blkdev.h | |
| parent | blk-mq: split blk_mq_alloc_and_init_hctx into two parts (diff) | |
| download | linux-dev-2f8f1336a48bd5186de3476da0a3e2ec06d0533a.tar.xz linux-dev-2f8f1336a48bd5186de3476da0a3e2ec06d0533a.zip | |
blk-mq: always free hctx after request queue is freed
In normal queue cleanup path, hctx is released after request queue
is freed, see blk_mq_release().
However, in __blk_mq_update_nr_hw_queues(), hctx may be freed because
of hw queues shrinking. This way is easy to cause use-after-free,
because: one implicit rule is that it is safe to call almost all block
layer APIs if the request queue is alive; and one hctx may be retrieved
by one API, then the hctx can be freed by blk_mq_update_nr_hw_queues();
finally use-after-free is triggered.
Fixes this issue by always freeing hctx after releasing request queue.
If some hctxs are removed in blk_mq_update_nr_hw_queues(), introduce
a per-queue list to hold them, then try to resuse these hctxs if numa
node is matched.
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: linux-scsi@vger.kernel.org,
Cc: Martin K . Petersen <martin.petersen@oracle.com>,
Cc: Christoph Hellwig <hch@lst.de>,
Cc: James E . J . Bottomley <jejb@linux.vnet.ibm.com>,
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '')
| -rw-r--r-- | include/linux/blkdev.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bd3e3f09bfa0..1aafeb923e7b 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -535,6 +535,13 @@ struct request_queue { struct mutex sysfs_lock; + /* + * for reusing dead hctx instance in case of updating + * nr_hw_queues + */ + struct list_head unused_hctx_list; + spinlock_t unused_hctx_lock; + atomic_t mq_freeze_depth; #if defined(CONFIG_BLK_DEV_BSG) |