blk-mq: add helper to insert requests from irq context
Both the cache flush state machine and the SCSI midlayer want to submit
requests from irq context, and the current per-request requeue_work
unfortunately causes corruption due to sharing with the csd field for
flushes. Replace them with a per-request_queue list of requests to
be requeued.
Based on an earlier test by Ming Lei.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 5b171fb..b9a74a3 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -172,6 +172,8 @@
void __blk_mq_end_io(struct request *rq, int error);
void blk_mq_requeue_request(struct request *rq);
+void blk_mq_add_to_requeue_list(struct request *rq, bool at_head);
+void blk_mq_kick_requeue_list(struct request_queue *q);
void blk_mq_complete_request(struct request *rq);
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6bc011a..913f1c2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -99,7 +99,6 @@
struct list_head queuelist;
union {
struct call_single_data csd;
- struct work_struct requeue_work;
unsigned long fifo_time;
};
@@ -463,6 +462,10 @@
struct request *flush_rq;
spinlock_t mq_flush_lock;
+ struct list_head requeue_list;
+ spinlock_t requeue_lock;
+ struct work_struct requeue_work;
+
struct mutex sysfs_lock;
int bypass_depth;