Commit f26cdc85 authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
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blk-mq: Shared tag enhancements



Storage controllers may expose multiple block devices that share hardware
resources managed by blk-mq. This patch enhances the shared tags so a
low-level driver can access the shared resources not tied to the unshared
h/w contexts. This way the LLD can dynamically add and delete disks and
request queues without having to track all the request_queue hctx's to
iterate outstanding tags.
Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent e548ca4e
......@@ -438,6 +438,39 @@ static void bt_for_each(struct blk_mq_hw_ctx *hctx,
}
}
static void bt_tags_for_each(struct blk_mq_tags *tags,
struct blk_mq_bitmap_tags *bt, unsigned int off,
busy_tag_iter_fn *fn, void *data, bool reserved)
{
struct request *rq;
int bit, i;
if (!tags->rqs)
return;
for (i = 0; i < bt->map_nr; i++) {
struct blk_align_bitmap *bm = &bt->map[i];
for (bit = find_first_bit(&bm->word, bm->depth);
bit < bm->depth;
bit = find_next_bit(&bm->word, bm->depth, bit + 1)) {
rq = blk_mq_tag_to_rq(tags, off + bit);
fn(rq, data, reserved);
}
off += (1 << bt->bits_per_word);
}
}
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, 0, fn, priv, true);
bt_tags_for_each(tags, &tags->bitmap_tags, tags->nr_reserved_tags, fn, priv,
false);
}
EXPORT_SYMBOL(blk_mq_all_tag_busy_iter);
void blk_mq_tag_busy_iter(struct blk_mq_hw_ctx *hctx, busy_iter_fn *fn,
void *priv)
{
......@@ -580,6 +613,11 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
if (!tags)
return NULL;
if (!zalloc_cpumask_var(&tags->cpumask, GFP_KERNEL)) {
kfree(tags);
return NULL;
}
tags->nr_tags = total_tags;
tags->nr_reserved_tags = reserved_tags;
......
......@@ -44,6 +44,7 @@ struct blk_mq_tags {
struct list_head page_list;
int alloc_policy;
cpumask_var_t cpumask;
};
......
......@@ -1525,7 +1525,6 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
i++;
}
}
return tags;
fail:
......@@ -1821,6 +1820,7 @@ static void blk_mq_map_swqueue(struct request_queue *q)
hctx = q->mq_ops->map_queue(q, i);
cpumask_set_cpu(i, hctx->cpumask);
cpumask_set_cpu(i, hctx->tags->cpumask);
ctx->index_hw = hctx->nr_ctx;
hctx->ctxs[hctx->nr_ctx++] = ctx;
}
......@@ -2187,6 +2187,12 @@ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
return 0;
}
struct cpumask *blk_mq_tags_cpumask(struct blk_mq_tags *tags)
{
return tags->cpumask;
}
EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask);
/*
* Alloc a tag set to be associated with one or more request queues.
* May fail with EINVAL for various error conditions. May adjust the
......@@ -2248,8 +2254,10 @@ void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
int i;
for (i = 0; i < set->nr_hw_queues; i++) {
if (set->tags[i])
if (set->tags[i]) {
blk_mq_free_rq_map(set, set->tags[i], i);
free_cpumask_var(set->tags[i]->cpumask);
}
}
kfree(set->tags);
......
......@@ -96,6 +96,7 @@ typedef void (exit_request_fn)(void *, struct request *, unsigned int,
typedef void (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
bool);
typedef void (busy_tag_iter_fn)(struct request *, void *, bool);
struct blk_mq_ops {
/*
......@@ -182,6 +183,7 @@ bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
gfp_t gfp, bool reserved);
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag);
struct cpumask *blk_mq_tags_cpumask(struct blk_mq_tags *tags);
enum {
BLK_MQ_UNIQUE_TAG_BITS = 16,
......@@ -224,6 +226,8 @@ void blk_mq_run_hw_queues(struct request_queue *q, bool async);
void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
void blk_mq_tag_busy_iter(struct blk_mq_hw_ctx *hctx, busy_iter_fn *fn,
void *priv);
void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
void *priv);
void blk_mq_freeze_queue(struct request_queue *q);
void blk_mq_unfreeze_queue(struct request_queue *q);
void blk_mq_freeze_queue_start(struct request_queue *q);
......
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