1 files changed, 35 insertions, 113 deletions

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 17ec83bb0900..1b8de0417fc1 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Functions related to generic timeout handling of requests.
  */
@@ -19,13 +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)
 {
@@ -57,12 +56,10 @@ ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr,
 		char *p = (char *) buf;
 
 		val = simple_strtoul(p, &p, 10);
-		spin_lock_irq(q->queue_lock);
 		if (val)
-			queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
+			blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
 		else
-			queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
-		spin_unlock_irq(q->queue_lock);
+			blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
 	}
 
 	return count;
@@ -70,112 +67,50 @@ ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr,
 
 #endif /* CONFIG_FAIL_IO_TIMEOUT */
 
-/*
- * blk_delete_timer - Delete/cancel timer for a given function.
- * @req:	request that we are canceling timer for
+/**
+ * blk_abort_request - Request recovery for the specified command
+ * @req:	pointer to the request of interest
  *
+ * This function requests that the block layer start recovery for the
+ * request by deleting the timer and calling the q's timeout function.
+ * LLDDs who implement their own error recovery MAY ignore the timeout
+ * event if they generated blk_abort_request.
  */
-void blk_delete_timer(struct request *req)
+void blk_abort_request(struct request *req)
 {
-	list_del_init(&req->timeout_list);
+	/*
+	 * All we need to ensure is that timeout scan takes place
+	 * immediately and that scan sees the new timeout value.
+	 * No need for fancy synchronizations.
+	 */
+	WRITE_ONCE(req->deadline, jiffies);
+	kblockd_schedule_work(&req->q->timeout_work);
 }
+EXPORT_SYMBOL_GPL(blk_abort_request);
 
-static void blk_rq_timed_out(struct request *req)
-{
-	struct request_queue *q = req->q;
-	enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
-
-	if (q->rq_timed_out_fn)
-		ret = q->rq_timed_out_fn(req);
-	switch (ret) {
-	case BLK_EH_HANDLED:
-		__blk_complete_request(req);
-		break;
-	case BLK_EH_RESET_TIMER:
-		blk_add_timer(req);
-		blk_clear_rq_complete(req);
-		break;
-	case BLK_EH_NOT_HANDLED:
-		/*
-		 * LLD handles this for now but in the future
-		 * we can send a request msg to abort the command
-		 * and we can move more of the generic scsi eh code to
-		 * the blk layer.
-		 */
-		break;
-	default:
-		printk(KERN_ERR "block: bad eh return: %d\n", ret);
-		break;
-	}
-}
+static unsigned long blk_timeout_mask __read_mostly;
 
-static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout,
-			  unsigned int *next_set)
+static int __init blk_timeout_init(void)
 {
-	if (time_after_eq(jiffies, rq->deadline)) {
-		list_del_init(&rq->timeout_list);
-
-		/*
-		 * Check if we raced with end io completion
-		 */
-		if (!blk_mark_rq_complete(rq))
-			blk_rq_timed_out(rq);
-	} else if (!*next_set || time_after(*next_timeout, rq->deadline)) {
-		*next_timeout = rq->deadline;
-		*next_set = 1;
-	}
+	blk_timeout_mask = roundup_pow_of_two(HZ) - 1;
+	return 0;
 }
 
-void blk_timeout_work(struct work_struct *work)
-{
-	struct request_queue *q =
-		container_of(work, struct request_queue, timeout_work);
-	unsigned long flags, next = 0;
-	struct request *rq, *tmp;
-	int next_set = 0;
-
-	if (blk_queue_enter(q, true))
-		return;
-	spin_lock_irqsave(q->queue_lock, flags);
-
-	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
-		blk_rq_check_expired(rq, &next, &next_set);
-
-	if (next_set)
-		mod_timer(&q->timeout, round_jiffies_up(next));
-
-	spin_unlock_irqrestore(q->queue_lock, flags);
-	blk_queue_exit(q);
-}
+late_initcall(blk_timeout_init);
 
-/**
- * blk_abort_request -- Request request recovery for the specified command
- * @req:	pointer to the request of interest
- *
- * This function requests that the block layer start recovery for the
- * request by deleting the timer and calling the q's timeout function.
- * LLDDs who implement their own error recovery MAY ignore the timeout
- * event if they generated blk_abort_req. Must hold queue lock.
+/*
+ * Just a rough estimate, we don't care about specific values for timeouts.
  */
-void blk_abort_request(struct request *req)
+static inline unsigned long blk_round_jiffies(unsigned long j)
 {
-	if (blk_mark_rq_complete(req))
-		return;
-
-	if (req->q->mq_ops) {
-		blk_mq_rq_timed_out(req, false);
-	} else {
-		blk_delete_timer(req);
-		blk_rq_timed_out(req);
-	}
+	return (j + blk_timeout_mask) + 1;
 }
-EXPORT_SYMBOL_GPL(blk_abort_request);
 
 unsigned long blk_rq_timeout(unsigned long timeout)
 {
 	unsigned long maxt;
 
-	maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT);
+	maxt = blk_round_jiffies(jiffies + BLK_MAX_TIMEOUT);
 	if (time_after(timeout, maxt))
 		timeout = maxt;
 
@@ -195,15 +130,6 @@ void blk_add_timer(struct request *req)
 	struct request_queue *q = req->q;
 	unsigned long expiry;
 
-	if (!q->mq_ops)
-		lockdep_assert_held(q->queue_lock);
-
-	/* blk-mq has its own handler, so we don't need ->rq_timed_out_fn */
-	if (!q->mq_ops && !q->rq_timed_out_fn)
-		return;
-
-	BUG_ON(!list_empty(&req->timeout_list));
-
 	/*
 	 * Some LLDs, like scsi, peek at the timeout to prevent a
 	 * command from being retried forever.
@@ -211,21 +137,17 @@ void blk_add_timer(struct request *req)
 	if (!req->timeout)
 		req->timeout = q->rq_timeout;
 
-	req->deadline = jiffies + req->timeout;
+	req->rq_flags &= ~RQF_TIMED_OUT;
 
-	/*
-	 * Only the non-mq case needs to add the request to a protected list.
-	 * For the mq case we simply scan the tag map.
-	 */
-	if (!q->mq_ops)
-		list_add_tail(&req->timeout_list, &req->q->timeout_list);
+	expiry = jiffies + req->timeout;
+	WRITE_ONCE(req->deadline, expiry);
 
 	/*
 	 * If the timer isn't already pending or this timeout is earlier
 	 * than an existing one, modify the timer. Round up to next nearest
 	 * second.
 	 */
-	expiry = blk_rq_timeout(round_jiffies_up(req->deadline));
+	expiry = blk_rq_timeout(blk_round_jiffies(expiry));
 
 	if (!timer_pending(&q->timeout) ||
 	    time_before(expiry, q->timeout.expires)) {