blk-mq: move failure injection out of blk_mq_complete_request

Move the call to blk_should_fake_timeout out of blk_mq_complete_request
and into the drivers, skipping call sites that are obvious error
handlers, and remove the now superflous blk_mq_force_complete_rq helper.
This ensures we don't keep injecting errors into completions that just
terminate the Linux request after the hardware has been reset or the
command has been aborted.

Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

4 files changed, 13 insertions, 41 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index ce772ab19188..3f4f227cf830 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -655,16 +655,13 @@ static void __blk_mq_complete_request_remote(void *data)
 }
 
 /**
- * blk_mq_force_complete_rq() - Force complete the request, bypassing any error
- * 				injection that could drop the completion.
- * @rq: Request to be force completed
+ * blk_mq_complete_request - end I/O on a request
+ * @rq:		the request being processed
  *
- * Drivers should use blk_mq_complete_request() to complete requests in their
- * normal IO path. For timeout error recovery, drivers may call this forced
- * completion routine after they've reclaimed timed out requests to bypass
- * potentially subsequent fake timeouts.
- */
-void blk_mq_force_complete_rq(struct request *rq)
+ * Description:
+ *	Complete a request by scheduling the ->complete_rq operation.
+ **/
+void blk_mq_complete_request(struct request *rq)
 {
 	struct blk_mq_ctx *ctx = rq->mq_ctx;
 	struct request_queue *q = rq->q;
@@ -702,7 +699,7 @@ void blk_mq_force_complete_rq(struct request *rq)
 	}
 	put_cpu();
 }
-EXPORT_SYMBOL_GPL(blk_mq_force_complete_rq);
+EXPORT_SYMBOL(blk_mq_complete_request);
 
 static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
 	__releases(hctx->srcu)
@@ -725,23 +722,6 @@ static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx)
 }
 
 /**
- * blk_mq_complete_request - end I/O on a request
- * @rq:		the request being processed
- *
- * Description:
- *	Ends all I/O on a request. It does not handle partial completions.
- *	The actual completion happens out-of-order, through a IPI handler.
- **/
-bool blk_mq_complete_request(struct request *rq)
-{
-	if (unlikely(blk_should_fake_timeout(rq->q)))
-		return false;
-	blk_mq_force_complete_rq(rq);
-	return true;
-}
-EXPORT_SYMBOL(blk_mq_complete_request);
-
-/**
  * blk_mq_start_request - Start processing a request
  * @rq: Pointer to request to be started
  *
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 8aa68fae96ad..3a1ac6434758 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -20,13 +20,11 @@ static int __init setup_fail_io_timeout(char *str)
 }
 __setup("fail_io_timeout=", setup_fail_io_timeout);
 
-int blk_should_fake_timeout(struct request_queue *q)
+bool __blk_should_fake_timeout(struct request_queue *q)
 {
-	if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags))
-		return 0;
-
 	return should_fail(&fail_io_timeout, 1);
 }
+EXPORT_SYMBOL_GPL(__blk_should_fake_timeout);
 
 static int __init fail_io_timeout_debugfs(void)
 {
diff --git a/block/blk.h b/block/blk.h
index b5d1f0fc6547..8ba4a5e4fe07 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -223,18 +223,9 @@ ssize_t part_fail_show(struct device *dev, struct device_attribute *attr,
 		char *buf);
 ssize_t part_fail_store(struct device *dev, struct device_attribute *attr,
 		const char *buf, size_t count);
-
-#ifdef CONFIG_FAIL_IO_TIMEOUT
-int blk_should_fake_timeout(struct request_queue *);
 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 				const char *, size_t);
-#else
-static inline int blk_should_fake_timeout(struct request_queue *q)
-{
-	return 0;
-}
-#endif
 
 void __blk_queue_split(struct request_queue *q, struct bio **bio,
 		unsigned int *nr_segs);
diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index 6cbb7926534c..fb7b347f8010 100644
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -181,9 +181,12 @@ EXPORT_SYMBOL_GPL(bsg_job_get);
 void bsg_job_done(struct bsg_job *job, int result,
 		  unsigned int reply_payload_rcv_len)
 {
+	struct request *rq = blk_mq_rq_from_pdu(job);
+
 	job->result = result;
 	job->reply_payload_rcv_len = reply_payload_rcv_len;
-	blk_mq_complete_request(blk_mq_rq_from_pdu(job));
+	if (likely(!blk_should_fake_timeout(rq->q)))
+		blk_mq_complete_request(rq);
 }
 EXPORT_SYMBOL_GPL(bsg_job_done);