[PATCH RFC 6/9] blk-mq: Refactor blk_mq_{alloc,free}_rqs

John Garry
2021-07-14T15:11:32Z

It will be required to be able to allocate and free static requests for a
tag set or a request queue (in addition to a struct blk_mq_tags), so break
out the common functionality of blk_mq_{alloc,free}_rqs, passing the
required static rqs ** and page list pointer to the core code.

Signed-off-by: John Garry <john.garry@huawei.com>
---
block/blk-mq.c | 61 +++++++++++++++++++++++++++++++++-----------------
block/blk-mq.h | 7 ++++++
2 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3ff5c15ce0eb..801af0993044 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2310,14 +2310,15 @@ static size_t order_to_size(unsigned int order)
}

/* called before freeing request pool in @tags */
-static void blk_mq_clear_rq_mapping(struct blk_mq_tag_set *set,
- struct blk_mq_tags *tags, unsigned int hctx_idx)
+void blk_mq_clear_rq_mapping(struct blk_mq_tag_set *set,
+ unsigned int hctx_idx,
+ struct list_head *page_list)
{
struct blk_mq_tags *drv_tags = set->tags[hctx_idx];
struct page *page;
unsigned long flags;

- list_for_each_entry(page, &tags->page_list, lru) {
+ list_for_each_entry(page, page_list, lru) {
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + order_to_size(page->private);
int i;
@@ -2343,28 +2344,29 @@ static void blk_mq_clear_rq_mapping(struct blk_mq_tag_set *set,
spin_unlock_irqrestore(&drv_tags->lock, flags);
}

-void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
- unsigned int hctx_idx)
+void __blk_mq_free_rqs(struct blk_mq_tag_set *set, unsigned int hctx_idx,
+ unsigned int depth, struct list_head *page_list,
+ struct request **static_rqs)
{
struct page *page;

- if (tags->static_rqs && set->ops->exit_request) {
+ if (static_rqs && set->ops->exit_request) {
int i;

- for (i = 0; i < tags->nr_tags; i++) {
- struct request *rq = tags->static_rqs[i];
+ for (i = 0; i < depth; i++) {
+ struct request *rq = static_rqs[i];

if (!rq)
continue;
set->ops->exit_request(set, rq, hctx_idx);
- tags->static_rqs[i] = NULL;
+ static_rqs[i] = NULL;
}
}

- blk_mq_clear_rq_mapping(set, tags, hctx_idx);
+ blk_mq_clear_rq_mapping(set, hctx_idx, page_list);

- while (!list_empty(&tags->page_list)) {
- page = list_first_entry(&tags->page_list, struct page, lru);
+ while (!list_empty(page_list)) {
+ page = list_first_entry(page_list, struct page, lru);
list_del_init(&page->lru);
/*
* Remove kmemleak object previously allocated in
@@ -2375,6 +2377,13 @@ void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
}
}

+void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
+ unsigned int hctx_idx)
+{
+ __blk_mq_free_rqs(set, hctx_idx, tags->nr_tags, &tags->page_list,
+ tags->static_rqs);
+}
+
void blk_mq_free_rq_map(struct blk_mq_tags *tags, unsigned int flags)
{
kfree(tags->rqs);
@@ -2437,8 +2446,10 @@ static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
return 0;
}

-int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
- unsigned int hctx_idx, unsigned int depth)
+
+int __blk_mq_alloc_rqs(struct blk_mq_tag_set *set, unsigned int hctx_idx,
+ unsigned int depth, struct list_head *page_list,
+ struct request **static_rqs)
{
unsigned int i, j, entries_per_page, max_order = 4;
size_t rq_size, left;
@@ -2448,7 +2459,7 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
if (node == NUMA_NO_NODE)
node = set->numa_node;

- INIT_LIST_HEAD(&tags->page_list);
+ INIT_LIST_HEAD(page_list);

/*
* rq_size is the size of the request plus driver payload, rounded
@@ -2483,7 +2494,7 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
goto fail;

page->private = this_order;
- list_add_tail(&page->lru, &tags->page_list);
+ list_add_tail(&page->lru, page_list);

p = page_address(page);
/*
@@ -2497,9 +2508,9 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
for (j = 0; j < to_do; j++) {
struct request *rq = p;

- tags->static_rqs[i] = rq;
+ static_rqs[i] = rq;
if (blk_mq_init_request(set, rq, hctx_idx, node)) {
- tags->static_rqs[i] = NULL;
+ static_rqs[i] = NULL;
goto fail;
}

@@ -2510,10 +2521,17 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
return 0;

fail:
- blk_mq_free_rqs(set, tags, hctx_idx);
+ __blk_mq_free_rqs(set, hctx_idx, depth, page_list, static_rqs);
return -ENOMEM;
}

+int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
+ unsigned int hctx_idx, unsigned int depth)
+{
+ return __blk_mq_alloc_rqs(set, hctx_idx, depth, &tags->page_list,
+ tags->static_rqs);
+}
+
struct rq_iter_data {
struct blk_mq_hw_ctx *hctx;
bool has_rq;
@@ -2856,12 +2874,13 @@ static bool __blk_mq_alloc_map_and_request(struct blk_mq_tag_set *set,
int ret = 0;

set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
- set->queue_depth, set->reserved_tags, flags);
+ set->queue_depth,
+ set->reserved_tags, flags);
if (!set->tags[hctx_idx])
return false;

ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx,
- set->queue_depth);
+ set->queue_depth);
if (!ret)
return true;

diff --git a/block/blk-mq.h b/block/blk-mq.h
index d08779f77a26..1e0fbb06412b 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -54,6 +54,9 @@ void blk_mq_put_rq_ref(struct request *rq);
*/
void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
unsigned int hctx_idx);
+void __blk_mq_free_rqs(struct blk_mq_tag_set *set, unsigned int hctx_idx,
+ unsigned int depth, struct list_head *page_list,
+ struct request **static_rqs);
void blk_mq_free_rq_map(struct blk_mq_tags *tags, unsigned int flags);
struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
unsigned int hctx_idx,
@@ -63,6 +66,10 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
unsigned int hctx_idx, unsigned int depth);

+int __blk_mq_alloc_rqs(struct blk_mq_tag_set *set, unsigned int hctx_idx,
+ unsigned int depth, struct list_head *page_list,
+ struct request **static_rqs);
+
/*
* Internal helpers for request insertion into sw queues
*/
--
2.26.2