Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 482 insertions, 0 deletions

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
new file mode 100644
index 000000000..41317c50a
--- /dev/null
+++ b/block/blk-mq-tag.c
@@ -0,0 +1,482 @@
+/*
+ * Tag allocation using scalable bitmaps. Uses active queue tracking to support
+ * fairer distribution of tags between multiple submitters when a shared tag map
+ * is used.
+ *
+ * Copyright (C) 2013-2014 Jens Axboe
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <linux/blk-mq.h>
+#include "blk.h"
+#include "blk-mq.h"
+#include "blk-mq-tag.h"
+
+bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
+{
+	if (!tags)
+		return true;
+
+	return sbitmap_any_bit_clear(&tags->bitmap_tags.sb);
+}
+
+/*
+ * If a previously inactive queue goes active, bump the active user count.
+ * We need to do this before try to allocate driver tag, then even if fail
+ * to get tag when first time, the other shared-tag users could reserve
+ * budget for it.
+ */
+bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
+{
+	if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
+	    !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+		atomic_inc(&hctx->tags->active_queues);
+
+	return true;
+}
+
+/*
+ * Wakeup all potentially sleeping on tags
+ */
+void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
+{
+	sbitmap_queue_wake_all(&tags->bitmap_tags);
+	if (include_reserve)
+		sbitmap_queue_wake_all(&tags->breserved_tags);
+}
+
+/*
+ * If a previously busy queue goes inactive, potential waiters could now
+ * be allowed to queue. Wake them up and check.
+ */
+void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
+{
+	struct blk_mq_tags *tags = hctx->tags;
+
+	if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+		return;
+
+	atomic_dec(&tags->active_queues);
+
+	blk_mq_tag_wakeup_all(tags, false);
+}
+
+/*
+ * For shared tag users, we track the number of currently active users
+ * and attempt to provide a fair share of the tag depth for each of them.
+ */
+static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
+				  struct sbitmap_queue *bt)
+{
+	unsigned int depth, users;
+
+	if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED))
+		return true;
+	if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+		return true;
+
+	/*
+	 * Don't try dividing an ant
+	 */
+	if (bt->sb.depth == 1)
+		return true;
+
+	users = atomic_read(&hctx->tags->active_queues);
+	if (!users)
+		return true;
+
+	/*
+	 * Allow at least some tags
+	 */
+	depth = max((bt->sb.depth + users - 1) / users, 4U);
+	return atomic_read(&hctx->nr_active) < depth;
+}
+
+static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
+			    struct sbitmap_queue *bt)
+{
+	if (!(data->flags & BLK_MQ_REQ_INTERNAL) &&
+	    !hctx_may_queue(data->hctx, bt))
+		return -1;
+	if (data->shallow_depth)
+		return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
+	else
+		return __sbitmap_queue_get(bt);
+}
+
+unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
+{
+	struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
+	struct sbitmap_queue *bt;
+	struct sbq_wait_state *ws;
+	DEFINE_WAIT(wait);
+	unsigned int tag_offset;
+	bool drop_ctx;
+	int tag;
+
+	if (data->flags & BLK_MQ_REQ_RESERVED) {
+		if (unlikely(!tags->nr_reserved_tags)) {
+			WARN_ON_ONCE(1);
+			return BLK_MQ_TAG_FAIL;
+		}
+		bt = &tags->breserved_tags;
+		tag_offset = 0;
+	} else {
+		bt = &tags->bitmap_tags;
+		tag_offset = tags->nr_reserved_tags;
+	}
+
+	tag = __blk_mq_get_tag(data, bt);
+	if (tag != -1)
+		goto found_tag;
+
+	if (data->flags & BLK_MQ_REQ_NOWAIT)
+		return BLK_MQ_TAG_FAIL;
+
+	ws = bt_wait_ptr(bt, data->hctx);
+	drop_ctx = data->ctx == NULL;
+	do {
+		struct sbitmap_queue *bt_prev;
+
+		/*
+		 * We're out of tags on this hardware queue, kick any
+		 * pending IO submits before going to sleep waiting for
+		 * some to complete.
+		 */
+		blk_mq_run_hw_queue(data->hctx, false);
+
+		/*
+		 * Retry tag allocation after running the hardware queue,
+		 * as running the queue may also have found completions.
+		 */
+		tag = __blk_mq_get_tag(data, bt);
+		if (tag != -1)
+			break;
+
+		prepare_to_wait_exclusive(&ws->wait, &wait,
+						TASK_UNINTERRUPTIBLE);
+
+		tag = __blk_mq_get_tag(data, bt);
+		if (tag != -1)
+			break;
+
+		if (data->ctx)
+			blk_mq_put_ctx(data->ctx);
+
+		bt_prev = bt;
+		io_schedule();
+
+		data->ctx = blk_mq_get_ctx(data->q);
+		data->hctx = blk_mq_map_queue(data->q, data->ctx->cpu);
+		tags = blk_mq_tags_from_data(data);
+		if (data->flags & BLK_MQ_REQ_RESERVED)
+			bt = &tags->breserved_tags;
+		else
+			bt = &tags->bitmap_tags;
+
+		finish_wait(&ws->wait, &wait);
+
+		/*
+		 * If destination hw queue is changed, fake wake up on
+		 * previous queue for compensating the wake up miss, so
+		 * other allocations on previous queue won't be starved.
+		 */
+		if (bt != bt_prev)
+			sbitmap_queue_wake_up(bt_prev);
+
+		ws = bt_wait_ptr(bt, data->hctx);
+	} while (1);
+
+	if (drop_ctx && data->ctx)
+		blk_mq_put_ctx(data->ctx);
+
+	finish_wait(&ws->wait, &wait);
+
+found_tag:
+	return tag + tag_offset;
+}
+
+void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
+		    struct blk_mq_ctx *ctx, unsigned int tag)
+{
+	if (!blk_mq_tag_is_reserved(tags, tag)) {
+		const int real_tag = tag - tags->nr_reserved_tags;
+
+		BUG_ON(real_tag >= tags->nr_tags);
+		sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
+	} else {
+		BUG_ON(tag >= tags->nr_reserved_tags);
+		sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
+	}
+}
+
+struct bt_iter_data {
+	struct blk_mq_hw_ctx *hctx;
+	busy_iter_fn *fn;
+	void *data;
+	bool reserved;
+};
+
+static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
+{
+	struct bt_iter_data *iter_data = data;
+	struct blk_mq_hw_ctx *hctx = iter_data->hctx;
+	struct blk_mq_tags *tags = hctx->tags;
+	bool reserved = iter_data->reserved;
+	struct request *rq;
+
+	if (!reserved)
+		bitnr += tags->nr_reserved_tags;
+	rq = tags->rqs[bitnr];
+
+	/*
+	 * We can hit rq == NULL here, because the tagging functions
+	 * test and set the bit before assining ->rqs[].
+	 */
+	if (rq && rq->q == hctx->queue)
+		iter_data->fn(hctx, rq, iter_data->data, reserved);
+	return true;
+}
+
+static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
+			busy_iter_fn *fn, void *data, bool reserved)
+{
+	struct bt_iter_data iter_data = {
+		.hctx = hctx,
+		.fn = fn,
+		.data = data,
+		.reserved = reserved,
+	};
+
+	sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
+}
+
+struct bt_tags_iter_data {
+	struct blk_mq_tags *tags;
+	busy_tag_iter_fn *fn;
+	void *data;
+	bool reserved;
+};
+
+static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
+{
+	struct bt_tags_iter_data *iter_data = data;
+	struct blk_mq_tags *tags = iter_data->tags;
+	bool reserved = iter_data->reserved;
+	struct request *rq;
+
+	if (!reserved)
+		bitnr += tags->nr_reserved_tags;
+
+	/*
+	 * We can hit rq == NULL here, because the tagging functions
+	 * test and set the bit before assining ->rqs[].
+	 */
+	rq = tags->rqs[bitnr];
+	if (rq && blk_mq_request_started(rq))
+		iter_data->fn(rq, iter_data->data, reserved);
+
+	return true;
+}
+
+static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
+			     busy_tag_iter_fn *fn, void *data, bool reserved)
+{
+	struct bt_tags_iter_data iter_data = {
+		.tags = tags,
+		.fn = fn,
+		.data = data,
+		.reserved = reserved,
+	};
+
+	if (tags->rqs)
+		sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
+}
+
+static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
+		busy_tag_iter_fn *fn, void *priv)
+{
+	if (tags->nr_reserved_tags)
+		bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true);
+	bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
+}
+
+void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
+		busy_tag_iter_fn *fn, void *priv)
+{
+	int i;
+
+	for (i = 0; i < tagset->nr_hw_queues; i++) {
+		if (tagset->tags && tagset->tags[i])
+			blk_mq_all_tag_busy_iter(tagset->tags[i], fn, priv);
+	}
+}
+EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
+
+void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
+		void *priv)
+{
+	struct blk_mq_hw_ctx *hctx;
+	int i;
+
+	/*
+	 * __blk_mq_update_nr_hw_queues will update the nr_hw_queues and
+	 * queue_hw_ctx after freeze the queue, so we use q_usage_counter
+	 * to avoid race with it.
+	 */
+	if (!percpu_ref_tryget(&q->q_usage_counter))
+		return;
+
+	queue_for_each_hw_ctx(q, hctx, i) {
+		struct blk_mq_tags *tags = hctx->tags;
+
+		/*
+		 * If not software queues are currently mapped to this
+		 * hardware queue, there's nothing to check
+		 */
+		if (!blk_mq_hw_queue_mapped(hctx))
+			continue;
+
+		if (tags->nr_reserved_tags)
+			bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
+		bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
+	}
+	blk_queue_exit(q);
+}
+
+static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
+		    bool round_robin, int node)
+{
+	return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
+				       node);
+}
+
+static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
+						   int node, int alloc_policy)
+{
+	unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
+	bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
+
+	if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node))
+		goto free_tags;
+	if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, round_robin,
+		     node))
+		goto free_bitmap_tags;
+
+	return tags;
+free_bitmap_tags:
+	sbitmap_queue_free(&tags->bitmap_tags);
+free_tags:
+	kfree(tags);
+	return NULL;
+}
+
+struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
+				     unsigned int reserved_tags,
+				     int node, int alloc_policy)
+{
+	struct blk_mq_tags *tags;
+
+	if (total_tags > BLK_MQ_TAG_MAX) {
+		pr_err("blk-mq: tag depth too large\n");
+		return NULL;
+	}
+
+	tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
+	if (!tags)
+		return NULL;
+
+	tags->nr_tags = total_tags;
+	tags->nr_reserved_tags = reserved_tags;
+
+	return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
+}
+
+void blk_mq_free_tags(struct blk_mq_tags *tags)
+{
+	sbitmap_queue_free(&tags->bitmap_tags);
+	sbitmap_queue_free(&tags->breserved_tags);
+	kfree(tags);
+}
+
+int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
+			    struct blk_mq_tags **tagsptr, unsigned int tdepth,
+			    bool can_grow)
+{
+	struct blk_mq_tags *tags = *tagsptr;
+
+	if (tdepth <= tags->nr_reserved_tags)
+		return -EINVAL;
+
+	/*
+	 * If we are allowed to grow beyond the original size, allocate
+	 * a new set of tags before freeing the old one.
+	 */
+	if (tdepth > tags->nr_tags) {
+		struct blk_mq_tag_set *set = hctx->queue->tag_set;
+		struct blk_mq_tags *new;
+		bool ret;
+
+		if (!can_grow)
+			return -EINVAL;
+
+		/*
+		 * We need some sort of upper limit, set it high enough that
+		 * no valid use cases should require more.
+		 */
+		if (tdepth > 16 * BLKDEV_MAX_RQ)
+			return -EINVAL;
+
+		new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth,
+				tags->nr_reserved_tags);
+		if (!new)
+			return -ENOMEM;
+		ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
+		if (ret) {
+			blk_mq_free_rq_map(new);
+			return -ENOMEM;
+		}
+
+		blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
+		blk_mq_free_rq_map(*tagsptr);
+		*tagsptr = new;
+	} else {
+		/*
+		 * Don't need (or can't) update reserved tags here, they
+		 * remain static and should never need resizing.
+		 */
+		sbitmap_queue_resize(&tags->bitmap_tags,
+				tdepth - tags->nr_reserved_tags);
+	}
+
+	return 0;
+}
+
+/**
+ * blk_mq_unique_tag() - return a tag that is unique queue-wide
+ * @rq: request for which to compute a unique tag
+ *
+ * The tag field in struct request is unique per hardware queue but not over
+ * all hardware queues. Hence this function that returns a tag with the
+ * hardware context index in the upper bits and the per hardware queue tag in
+ * the lower bits.
+ *
+ * Note: When called for a request that is queued on a non-multiqueue request
+ * queue, the hardware context index is set to zero.
+ */
+u32 blk_mq_unique_tag(struct request *rq)
+{
+	struct request_queue *q = rq->q;
+	struct blk_mq_hw_ctx *hctx;
+	int hwq = 0;
+
+	if (q->mq_ops) {
+		hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu);
+		hwq = hctx->queue_num;
+	}
+
+	return (hwq << BLK_MQ_UNIQUE_TAG_BITS) |
+		(rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
+}
+EXPORT_SYMBOL(blk_mq_unique_tag);