1 files changed, 148 insertions, 142 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 03252af8c82c..d9d632639bd1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -51,9 +51,7 @@
 #include "blk-pm.h"
 #include "blk-rq-qos.h"
 
-#ifdef CONFIG_DEBUG_FS
 struct dentry *blk_debugfs_root;
-#endif
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
@@ -285,7 +283,7 @@ EXPORT_SYMBOL(blk_dump_rq_flags);
  *     A block device may call blk_sync_queue to ensure that any
  *     such activity is cancelled, thus allowing it to release resources
  *     that the callbacks might use. The caller must already have made sure
- *     that its ->make_request_fn will not re-add plugging prior to calling
+ *     that its ->submit_bio will not re-add plugging prior to calling
  *     this function.
  *
  *     This function does not cancel any asynchronous activity arising
@@ -321,6 +319,16 @@ void blk_clear_pm_only(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_clear_pm_only);
 
+/**
+ * blk_put_queue - decrement the request_queue refcount
+ * @q: the request_queue structure to decrement the refcount for
+ *
+ * Decrements the refcount of the request_queue kobject. When this reaches 0
+ * we'll have blk_release_queue() called.
+ *
+ * Context: Any context, but the last reference must not be dropped from
+ *          atomic context.
+ */
 void blk_put_queue(struct request_queue *q)
 {
 	kobject_put(&q->kobj);
@@ -352,9 +360,14 @@ EXPORT_SYMBOL_GPL(blk_set_queue_dying);
  *
  * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
  * put it.  All future requests will be failed immediately with -ENODEV.
+ *
+ * Context: can sleep
  */
 void blk_cleanup_queue(struct request_queue *q)
 {
+	/* cannot be called from atomic context */
+	might_sleep();
+
 	WARN_ON_ONCE(blk_queue_registered(q));
 
 	/* mark @q DYING, no new request or merges will be allowed afterwards */
@@ -497,7 +510,7 @@ static void blk_timeout_work(struct work_struct *work)
 {
 }
 
-struct request_queue *__blk_alloc_queue(int node_id)
+struct request_queue *blk_alloc_queue(int node_id)
 {
 	struct request_queue *q;
 	int ret;
@@ -540,9 +553,7 @@ struct request_queue *__blk_alloc_queue(int node_id)
 
 	kobject_init(&q->kobj, &blk_queue_ktype);
 
-#ifdef CONFIG_BLK_DEV_IO_TRACE
-	mutex_init(&q->blk_trace_mutex);
-#endif
+	mutex_init(&q->debugfs_mutex);
 	mutex_init(&q->sysfs_lock);
 	mutex_init(&q->sysfs_dir_lock);
 	spin_lock_init(&q->queue_lock);
@@ -564,6 +575,7 @@ struct request_queue *__blk_alloc_queue(int node_id)
 
 	blk_queue_dma_alignment(q, 511);
 	blk_set_default_limits(&q->limits);
+	q->nr_requests = BLKDEV_MAX_RQ;
 
 	return q;
 
@@ -581,23 +593,16 @@ fail_q:
 	kmem_cache_free(blk_requestq_cachep, q);
 	return NULL;
 }
-
-struct request_queue *blk_alloc_queue(make_request_fn make_request, int node_id)
-{
-	struct request_queue *q;
-
-	if (WARN_ON_ONCE(!make_request))
-		return NULL;
-
-	q = __blk_alloc_queue(node_id);
-	if (!q)
-		return NULL;
-	q->make_request_fn = make_request;
-	q->nr_requests = BLKDEV_MAX_RQ;
-	return q;
-}
 EXPORT_SYMBOL(blk_alloc_queue);
 
+/**
+ * blk_get_queue - increment the request_queue refcount
+ * @q: the request_queue structure to increment the refcount for
+ *
+ * Increment the refcount of the request_queue kobject.
+ *
+ * Context: Any context.
+ */
 bool blk_get_queue(struct request_queue *q)
 {
 	if (likely(!blk_queue_dying(q))) {
@@ -850,8 +855,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
 			return false;
 
 		WARN_ONCE(1,
-		       "generic_make_request: Trying to write "
-			"to read-only block-device %s (partno %d)\n",
+		       "Trying to write to read-only block-device %s (partno %d)\n",
 			bio_devname(bio, b), part->partno);
 		/* Older lvm-tools actually trigger this */
 		return false;
@@ -952,24 +956,17 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q,
 	return BLK_STS_OK;
 }
 
-static noinline_for_stack bool
-generic_make_request_checks(struct bio *bio)
+static noinline_for_stack bool submit_bio_checks(struct bio *bio)
 {
-	struct request_queue *q;
-	int nr_sectors = bio_sectors(bio);
+	struct request_queue *q = bio->bi_disk->queue;
 	blk_status_t status = BLK_STS_IOERR;
-	char b[BDEVNAME_SIZE];
+	struct blk_plug *plug;
 
 	might_sleep();
 
-	q = bio->bi_disk->queue;
-	if (unlikely(!q)) {
-		printk(KERN_ERR
-		       "generic_make_request: Trying to access "
-			"nonexistent block-device %s (%Lu)\n",
-			bio_devname(bio, b), (long long)bio->bi_iter.bi_sector);
-		goto end_io;
-	}
+	plug = blk_mq_plug(q, bio);
+	if (plug && plug->nowait)
+		bio->bi_opf |= REQ_NOWAIT;
 
 	/*
 	 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
@@ -992,14 +989,13 @@ generic_make_request_checks(struct bio *bio)
 	}
 
 	/*
-	 * Filter flush bio's early so that make_request based
-	 * drivers without flush support don't have to worry
-	 * about them.
+	 * Filter flush bio's early so that bio based drivers without flush
+	 * support don't have to worry about them.
 	 */
 	if (op_is_flush(bio->bi_opf) &&
 	    !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
 		bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
-		if (!nr_sectors) {
+		if (!bio_sectors(bio)) {
 			status = BLK_STS_OK;
 			goto end_io;
 		}
@@ -1054,8 +1050,13 @@ generic_make_request_checks(struct bio *bio)
 	if (unlikely(!current->io_context))
 		create_task_io_context(current, GFP_ATOMIC, q->node);
 
-	if (!blkcg_bio_issue_check(q, bio))
+	if (blk_throtl_bio(bio)) {
+		blkcg_bio_issue_init(bio);
 		return false;
+	}
+
+	blk_cgroup_bio_start(bio);
+	blkcg_bio_issue_init(bio);
 
 	if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
 		trace_block_bio_queue(q, bio);
@@ -1074,138 +1075,144 @@ end_io:
 	return false;
 }
 
-static blk_qc_t do_make_request(struct bio *bio)
+static blk_qc_t __submit_bio(struct bio *bio)
 {
-	struct request_queue *q = bio->bi_disk->queue;
+	struct gendisk *disk = bio->bi_disk;
 	blk_qc_t ret = BLK_QC_T_NONE;
 
 	if (blk_crypto_bio_prep(&bio)) {
-		if (!q->make_request_fn)
-			return blk_mq_make_request(q, bio);
-		ret = q->make_request_fn(q, bio);
+		if (!disk->fops->submit_bio)
+			return blk_mq_submit_bio(bio);
+		ret = disk->fops->submit_bio(bio);
 	}
-	blk_queue_exit(q);
+	blk_queue_exit(disk->queue);
 	return ret;
 }
 
-/**
- * generic_make_request - re-submit a bio to the block device layer for I/O
- * @bio:  The bio describing the location in memory and on the device.
+/*
+ * The loop in this function may be a bit non-obvious, and so deserves some
+ * explanation:
  *
- * This is a version of submit_bio() that shall only be used for I/O that is
- * resubmitted to lower level drivers by stacking block drivers.  All file
- * systems and other upper level users of the block layer should use
- * submit_bio() instead.
+ *  - Before entering the loop, bio->bi_next is NULL (as all callers ensure
+ *    that), so we have a list with a single bio.
+ *  - We pretend that we have just taken it off a longer list, so we assign
+ *    bio_list to a pointer to the bio_list_on_stack, thus initialising the
+ *    bio_list of new bios to be added.  ->submit_bio() may indeed add some more
+ *    bios through a recursive call to submit_bio_noacct.  If it did, we find a
+ *    non-NULL value in bio_list and re-enter the loop from the top.
+ *  - In this case we really did just take the bio of the top of the list (no
+ *    pretending) and so remove it from bio_list, and call into ->submit_bio()
+ *    again.
+ *
+ * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
+ * bio_list_on_stack[1] contains bios that were submitted before the current
+ *	->submit_bio_bio, but that haven't been processed yet.
  */
-blk_qc_t generic_make_request(struct bio *bio)
+static blk_qc_t __submit_bio_noacct(struct bio *bio)
 {
-	/*
-	 * bio_list_on_stack[0] contains bios submitted by the current
-	 * make_request_fn.
-	 * bio_list_on_stack[1] contains bios that were submitted before
-	 * the current make_request_fn, but that haven't been processed
-	 * yet.
-	 */
 	struct bio_list bio_list_on_stack[2];
 	blk_qc_t ret = BLK_QC_T_NONE;
 
-	if (!generic_make_request_checks(bio))
-		goto out;
-
-	/*
-	 * We only want one ->make_request_fn to be active at a time, else
-	 * stack usage with stacked devices could be a problem.  So use
-	 * current->bio_list to keep a list of requests submited by a
-	 * make_request_fn function.  current->bio_list is also used as a
-	 * flag to say if generic_make_request is currently active in this
-	 * task or not.  If it is NULL, then no make_request is active.  If
-	 * it is non-NULL, then a make_request is active, and new requests
-	 * should be added at the tail
-	 */
-	if (current->bio_list) {
-		bio_list_add(&current->bio_list[0], bio);
-		goto out;
-	}
-
-	/* following loop may be a bit non-obvious, and so deserves some
-	 * explanation.
-	 * Before entering the loop, bio->bi_next is NULL (as all callers
-	 * ensure that) so we have a list with a single bio.
-	 * We pretend that we have just taken it off a longer list, so
-	 * we assign bio_list to a pointer to the bio_list_on_stack,
-	 * thus initialising the bio_list of new bios to be
-	 * added.  ->make_request() may indeed add some more bios
-	 * through a recursive call to generic_make_request.  If it
-	 * did, we find a non-NULL value in bio_list and re-enter the loop
-	 * from the top.  In this case we really did just take the bio
-	 * of the top of the list (no pretending) and so remove it from
-	 * bio_list, and call into ->make_request() again.
-	 */
 	BUG_ON(bio->bi_next);
+
 	bio_list_init(&bio_list_on_stack[0]);
 	current->bio_list = bio_list_on_stack;
+
 	do {
 		struct request_queue *q = bio->bi_disk->queue;
+		struct bio_list lower, same;
+
+		if (unlikely(bio_queue_enter(bio) != 0))
+			continue;
 
-		if (likely(bio_queue_enter(bio) == 0)) {
-			struct bio_list lower, same;
+		/*
+		 * Create a fresh bio_list for all subordinate requests.
+		 */
+		bio_list_on_stack[1] = bio_list_on_stack[0];
+		bio_list_init(&bio_list_on_stack[0]);
 
-			/* Create a fresh bio_list for all subordinate requests */
-			bio_list_on_stack[1] = bio_list_on_stack[0];
-			bio_list_init(&bio_list_on_stack[0]);
-			ret = do_make_request(bio);
+		ret = __submit_bio(bio);
 
-			/* sort new bios into those for a lower level
-			 * and those for the same level
-			 */
-			bio_list_init(&lower);
-			bio_list_init(&same);
-			while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
-				if (q == bio->bi_disk->queue)
-					bio_list_add(&same, bio);
-				else
-					bio_list_add(&lower, bio);
-			/* now assemble so we handle the lowest level first */
-			bio_list_merge(&bio_list_on_stack[0], &lower);
-			bio_list_merge(&bio_list_on_stack[0], &same);
-			bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
+		/*
+		 * Sort new bios into those for a lower level and those for the
+		 * same level.
+		 */
+		bio_list_init(&lower);
+		bio_list_init(&same);
+		while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
+			if (q == bio->bi_disk->queue)
+				bio_list_add(&same, bio);
+			else
+				bio_list_add(&lower, bio);
+
+		/*
+		 * Now assemble so we handle the lowest level first.
+		 */
+		bio_list_merge(&bio_list_on_stack[0], &lower);
+		bio_list_merge(&bio_list_on_stack[0], &same);
+		bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
+	} while ((bio = bio_list_pop(&bio_list_on_stack[0])));
+
+	current->bio_list = NULL;
+	return ret;
+}
+
+static blk_qc_t __submit_bio_noacct_mq(struct bio *bio)
+{
+	struct bio_list bio_list[2] = { };
+	blk_qc_t ret = BLK_QC_T_NONE;
+
+	current->bio_list = bio_list;
+
+	do {
+		struct gendisk *disk = bio->bi_disk;
+
+		if (unlikely(bio_queue_enter(bio) != 0))
+			continue;
+
+		if (!blk_crypto_bio_prep(&bio)) {
+			blk_queue_exit(disk->queue);
+			ret = BLK_QC_T_NONE;
+			continue;
 		}
-		bio = bio_list_pop(&bio_list_on_stack[0]);
-	} while (bio);
-	current->bio_list = NULL; /* deactivate */
 
-out:
+		ret = blk_mq_submit_bio(bio);
+	} while ((bio = bio_list_pop(&bio_list[0])));
+
+	current->bio_list = NULL;
 	return ret;
 }
-EXPORT_SYMBOL(generic_make_request);
 
 /**
- * direct_make_request - hand a buffer directly to its device driver for I/O
+ * submit_bio_noacct - re-submit a bio to the block device layer for I/O
  * @bio:  The bio describing the location in memory and on the device.
  *
- * This function behaves like generic_make_request(), but does not protect
- * against recursion.  Must only be used if the called driver is known
- * to be blk-mq based.
+ * This is a version of submit_bio() that shall only be used for I/O that is
+ * resubmitted to lower level drivers by stacking block drivers.  All file
+ * systems and other upper level users of the block layer should use
+ * submit_bio() instead.
  */
-blk_qc_t direct_make_request(struct bio *bio)
+blk_qc_t submit_bio_noacct(struct bio *bio)
 {
-	struct request_queue *q = bio->bi_disk->queue;
-
-	if (WARN_ON_ONCE(q->make_request_fn)) {
-		bio_io_error(bio);
-		return BLK_QC_T_NONE;
-	}
-	if (!generic_make_request_checks(bio))
-		return BLK_QC_T_NONE;
-	if (unlikely(bio_queue_enter(bio)))
+	if (!submit_bio_checks(bio))
 		return BLK_QC_T_NONE;
-	if (!blk_crypto_bio_prep(&bio)) {
-		blk_queue_exit(q);
+
+	/*
+	 * We only want one ->submit_bio to be active at a time, else stack
+	 * usage with stacked devices could be a problem.  Use current->bio_list
+	 * to collect a list of requests submited by a ->submit_bio method while
+	 * it is active, and then process them after it returned.
+	 */
+	if (current->bio_list) {
+		bio_list_add(&current->bio_list[0], bio);
 		return BLK_QC_T_NONE;
 	}
-	return blk_mq_make_request(q, bio);
+
+	if (!bio->bi_disk->fops->submit_bio)
+		return __submit_bio_noacct_mq(bio);
+	return __submit_bio_noacct(bio);
 }
-EXPORT_SYMBOL_GPL(direct_make_request);
+EXPORT_SYMBOL(submit_bio_noacct);
 
 /**
  * submit_bio - submit a bio to the block device layer for I/O
@@ -1266,13 +1273,13 @@ blk_qc_t submit_bio(struct bio *bio)
 		blk_qc_t ret;
 
 		psi_memstall_enter(&pflags);
-		ret = generic_make_request(bio);
+		ret = submit_bio_noacct(bio);
 		psi_memstall_leave(&pflags);
 
 		return ret;
 	}
 
-	return generic_make_request(bio);
+	return submit_bio_noacct(bio);
 }
 EXPORT_SYMBOL(submit_bio);
 
@@ -1800,6 +1807,7 @@ void blk_start_plug(struct blk_plug *plug)
 	INIT_LIST_HEAD(&plug->cb_list);
 	plug->rq_count = 0;
 	plug->multiple_queues = false;
+	plug->nowait = false;
 
 	/*
 	 * Store ordering should not be needed here, since a potential
@@ -1908,9 +1916,7 @@ int __init blk_dev_init(void)
 	blk_requestq_cachep = kmem_cache_create("request_queue",
 			sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
 
-#ifdef CONFIG_DEBUG_FS
 	blk_debugfs_root = debugfs_create_dir("block", NULL);
-#endif
 
 	return 0;
 }