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blk-mq-tag: cleanup the normal/reserved tag allocation

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This is in preparation for having another tag set available. Cleanup
the parameters, and allow passing in of tags for blk_mq_put_tag().

Signed-off-by: Jens Axboe <axboe@fb.com>
[hch: even more cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
This commit is contained in:
Jens Axboe 2017-01-13 08:09:05 -07:00
parent 2c3ad66790
commit 4941115bef
4 changed files with 45 additions and 62 deletions
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96
block/blk-mq-tag.c
View File

@ -90,32 +90,46 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
return atomic_read(&hctx->nr_active) < depth;
}
static int __bt_get(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt)
static int __blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt)
{
if (!hctx_may_queue(hctx, bt))
return -1;
return __sbitmap_queue_get(bt);
}
static int bt_get(struct blk_mq_alloc_data *data, struct sbitmap_queue *bt,
struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags)
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;
int tag;
tag = __bt_get(hctx, bt);
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->hctx, bt);
if (tag != -1)
return tag;
goto found_tag;
if (data->flags & BLK_MQ_REQ_NOWAIT)
return -1;
return BLK_MQ_TAG_FAIL;
ws = bt_wait_ptr(bt, hctx);
ws = bt_wait_ptr(bt, data->hctx);
do {
prepare_to_wait(&ws->wait, &wait, TASK_UNINTERRUPTIBLE);
tag = __bt_get(hctx, bt);
tag = __blk_mq_get_tag(data->hctx, bt);
if (tag != -1)
break;
@ -125,14 +139,14 @@ static int bt_get(struct blk_mq_alloc_data *data, struct sbitmap_queue *bt,
* some to complete. Note that hctx can be NULL here for
* reserved tag allocation.
*/
if (hctx)
blk_mq_run_hw_queue(hctx, false);
if (data->hctx)
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 = __bt_get(hctx, bt);
tag = __blk_mq_get_tag(data->hctx, bt);
if (tag != -1)
break;
@ -142,61 +156,25 @@ static int bt_get(struct blk_mq_alloc_data *data, struct sbitmap_queue *bt,
data->ctx = blk_mq_get_ctx(data->q);
data->hctx = blk_mq_map_queue(data->q, data->ctx->cpu);
if (data->flags & BLK_MQ_REQ_RESERVED) {
bt = &data->hctx->tags->breserved_tags;
} else {
hctx = data->hctx;
bt = &hctx->tags->bitmap_tags;
}
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);
ws = bt_wait_ptr(bt, hctx);
ws = bt_wait_ptr(bt, data->hctx);
} while (1);
finish_wait(&ws->wait, &wait);
return tag;
found_tag:
return tag + tag_offset;
}
static unsigned int __blk_mq_get_tag(struct blk_mq_alloc_data *data)
void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
struct blk_mq_ctx *ctx, unsigned int tag)
{
int tag;
tag = bt_get(data, &data->hctx->tags->bitmap_tags, data->hctx,
data->hctx->tags);
if (tag >= 0)
return tag + data->hctx->tags->nr_reserved_tags;
return BLK_MQ_TAG_FAIL;
}
static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_alloc_data *data)
{
int tag;
if (unlikely(!data->hctx->tags->nr_reserved_tags)) {
WARN_ON_ONCE(1);
return BLK_MQ_TAG_FAIL;
}
tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL,
data->hctx->tags);
if (tag < 0)
return BLK_MQ_TAG_FAIL;
return tag;
}
unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
{
if (data->flags & BLK_MQ_REQ_RESERVED)
return __blk_mq_get_reserved_tag(data);
return __blk_mq_get_tag(data);
}
void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
unsigned int tag)
{
struct blk_mq_tags *tags = hctx->tags;
if (tag >= tags->nr_reserved_tags) {
const int real_tag = tag - tags->nr_reserved_tags;

4
block/blk-mq-tag.h
View File

@ -24,8 +24,8 @@ extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int r
extern void blk_mq_free_tags(struct blk_mq_tags *tags);
extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
unsigned int tag);
extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
struct blk_mq_ctx *ctx, unsigned int tag);
extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);
extern int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int depth);

2
block/blk-mq.c
View File

@ -335,7 +335,7 @@ void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
clear_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags);
blk_mq_put_tag(hctx, ctx, tag);
blk_mq_put_tag(hctx, hctx->tags, ctx, tag);
blk_queue_exit(q);
}

5
block/blk-mq.h
View File

@ -118,6 +118,11 @@ static inline void blk_mq_set_alloc_data(struct blk_mq_alloc_data *data,
data->hctx = hctx;
}
static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
{
return data->hctx->tags;
}
/*
* Internal helpers for request allocation/init/free
*/