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authorYu Kuai <yukuai3@huawei.com>2025-09-10 16:04:42 +0800
committerJens Axboe <axboe@kernel.dk>2025-09-10 05:25:56 -0600
commit6293e336f6d7d3f3415346ce34993b3398846166 (patch)
treeb7459e1521b4ab70b9f0f40e9361213f66f92080 /block
parentblk-mq: split bitmap grow and resize case in blk_mq_update_nr_requests() (diff)
downloadlinux-6293e336f6d7d3f3415346ce34993b3398846166.tar.gz
linux-6293e336f6d7d3f3415346ce34993b3398846166.zip
blk-mq-sched: add new parameter nr_requests in blk_mq_alloc_sched_tags()
This helper only support to allocate the default number of requests, add a new parameter to support specific number of requests. Prepare to fix potential deadlock in the case nr_requests grow. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq-sched.c14
-rw-r--r--block/blk-mq-sched.h2
-rw-r--r--block/blk-mq.h11
-rw-r--r--block/elevator.c3
4 files changed, 19 insertions, 11 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index e2ce4a28e6c9..d06bb137a743 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -454,7 +454,7 @@ void blk_mq_free_sched_tags_batch(struct xarray *et_table,
}
struct elevator_tags *blk_mq_alloc_sched_tags(struct blk_mq_tag_set *set,
- unsigned int nr_hw_queues)
+ unsigned int nr_hw_queues, unsigned int nr_requests)
{
unsigned int nr_tags;
int i;
@@ -470,13 +470,8 @@ struct elevator_tags *blk_mq_alloc_sched_tags(struct blk_mq_tag_set *set,
nr_tags * sizeof(struct blk_mq_tags *), gfp);
if (!et)
return NULL;
- /*
- * Default to double of smaller one between hw queue_depth and
- * 128, since we don't split into sync/async like the old code
- * did. Additionally, this is a per-hw queue depth.
- */
- et->nr_requests = 2 * min_t(unsigned int, set->queue_depth,
- BLKDEV_DEFAULT_RQ);
+
+ et->nr_requests = nr_requests;
et->nr_hw_queues = nr_hw_queues;
if (blk_mq_is_shared_tags(set->flags)) {
@@ -521,7 +516,8 @@ int blk_mq_alloc_sched_tags_batch(struct xarray *et_table,
* concurrently.
*/
if (q->elevator) {
- et = blk_mq_alloc_sched_tags(set, nr_hw_queues);
+ et = blk_mq_alloc_sched_tags(set, nr_hw_queues,
+ blk_mq_default_nr_requests(set));
if (!et)
goto out_unwind;
if (xa_insert(et_table, q->id, et, gfp))
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index fe83187f41db..8e21a6b1415d 100644
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -24,7 +24,7 @@ void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e);
void blk_mq_sched_free_rqs(struct request_queue *q);
struct elevator_tags *blk_mq_alloc_sched_tags(struct blk_mq_tag_set *set,
- unsigned int nr_hw_queues);
+ unsigned int nr_hw_queues, unsigned int nr_requests);
int blk_mq_alloc_sched_tags_batch(struct xarray *et_table,
struct blk_mq_tag_set *set, unsigned int nr_hw_queues);
void blk_mq_free_sched_tags(struct elevator_tags *et,
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 5d42c7d3a952..3a1d4c37d1bc 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -110,6 +110,17 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(blk_opf_t opf,
}
/*
+ * Default to double of smaller one between hw queue_depth and
+ * 128, since we don't split into sync/async like the old code
+ * did. Additionally, this is a per-hw queue depth.
+ */
+static inline unsigned int blk_mq_default_nr_requests(
+ struct blk_mq_tag_set *set)
+{
+ return 2 * min_t(unsigned int, set->queue_depth, BLKDEV_DEFAULT_RQ);
+}
+
+/*
* sysfs helpers
*/
extern void blk_mq_sysfs_init(struct request_queue *q);
diff --git a/block/elevator.c b/block/elevator.c
index fe96c6f4753c..e2ebfbf107b3 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -669,7 +669,8 @@ static int elevator_change(struct request_queue *q, struct elv_change_ctx *ctx)
lockdep_assert_held(&set->update_nr_hwq_lock);
if (strncmp(ctx->name, "none", 4)) {
- ctx->et = blk_mq_alloc_sched_tags(set, set->nr_hw_queues);
+ ctx->et = blk_mq_alloc_sched_tags(set, set->nr_hw_queues,
+ blk_mq_default_nr_requests(set));
if (!ctx->et)
return -ENOMEM;
}