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authorBart Van Assche <bvanassche@acm.org>2019-04-04 20:08:43 +0300
committerJens Axboe <axboe@kernel.dk>2019-04-05 18:40:46 +0300
commitfd9c40f64c514bdc585a21e2e33fa5f83ca8811b (patch)
tree6325afffd310da5e086f86dc27c4a79d375a5207 /block/blk-mq-sched.c
parentf0d1762554014ce0ae347b9f0d088f2c157c8c72 (diff)
downloadlinux-fd9c40f64c514bdc585a21e2e33fa5f83ca8811b.tar.xz
block: Revert v5.0 blk_mq_request_issue_directly() changes
blk_mq_try_issue_directly() can return BLK_STS*_RESOURCE for requests that have been queued. If that happens when blk_mq_try_issue_directly() is called by the dm-mpath driver then dm-mpath will try to resubmit a request that is already queued and a kernel crash follows. Since it is nontrivial to fix blk_mq_request_issue_directly(), revert the blk_mq_request_issue_directly() changes that went into kernel v5.0. This patch reverts the following commits: * d6a51a97c0b2 ("blk-mq: replace and kill blk_mq_request_issue_directly") # v5.0. * 5b7a6f128aad ("blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests") # v5.0. * 7f556a44e61d ("blk-mq: refactor the code of issue request directly") # v5.0. Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: James Smart <james.smart@broadcom.com> Cc: Dongli Zhang <dongli.zhang@oracle.com> Cc: Laurence Oberman <loberman@redhat.com> Cc: <stable@vger.kernel.org> Reported-by: Laurence Oberman <loberman@redhat.com> Tested-by: Laurence Oberman <loberman@redhat.com> Fixes: 7f556a44e61d ("blk-mq: refactor the code of issue request directly") # v5.0. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq-sched.c')
-rw-r--r--block/blk-mq-sched.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 40905539afed..aa6bc5c02643 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -423,10 +423,12 @@ void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
* busy in case of 'none' scheduler, and this way may save
* us one extra enqueue & dequeue to sw queue.
*/
- if (!hctx->dispatch_busy && !e && !run_queue_async)
+ if (!hctx->dispatch_busy && !e && !run_queue_async) {
blk_mq_try_issue_list_directly(hctx, list);
- else
- blk_mq_insert_requests(hctx, ctx, list);
+ if (list_empty(list))
+ return;
+ }
+ blk_mq_insert_requests(hctx, ctx, list);
}
blk_mq_run_hw_queue(hctx, run_queue_async);