From: Ming Lei <ming.lei@xxxxxxxxxx>
blk_mq_alloc_request_hctx() asks blk-mq to allocate request from a
specified hctx, which is usually bound with fixed cpu mapping, and
request is supposed to be allocated on CPU in hctx->cpumask.
Use smp_call_function_any() to allocate a request on a CPU that is set
in hctx->cpumask and return it in blk_mq_alloc_data instead to prepare
for better CPU hotplug support in blk-mq.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
[hch: reuse blk_mq_alloc_data for the smp_call_function_any argument]
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-mq.c | 24 ++++++++++++++++++------
block/blk-mq.h | 3 +++
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index fcfce666457e2..540b5845cd1d3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -386,6 +386,20 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data)
return rq;
}
+static void __blk_mq_alloc_request_cb(void *__data)
+{
+ struct blk_mq_alloc_data *data = __data;
+
+ data->rq = __blk_mq_alloc_request(data);
+}
+
+static struct request *__blk_mq_alloc_request_on_cpumask(const cpumask_t *mask,
+ struct blk_mq_alloc_data *data)
+{
+ smp_call_function_any(mask, __blk_mq_alloc_request_cb, data, 1);
+ return data->rq;
+}
+
struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
blk_mq_req_flags_t flags)
{
@@ -423,7 +437,7 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
.cmd_flags = op,
};
struct request *rq;
- unsigned int cpu;
+ struct blk_mq_hw_ctx *hctx;
int ret;
/*
@@ -447,14 +461,12 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
* If not tell the caller that it should skip this queue.
*/
ret = -EXDEV;
- data.hctx = q->queue_hw_ctx[hctx_idx];
- if (!blk_mq_hw_queue_mapped(data.hctx))
+ hctx = q->queue_hw_ctx[hctx_idx];
+ if (!blk_mq_hw_queue_mapped(hctx))
goto out_queue_exit;
- cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
- data.ctx = __blk_mq_get_ctx(q, cpu);
ret = -EWOULDBLOCK;
- rq = __blk_mq_alloc_request(&data);
+ rq = __blk_mq_alloc_request_on_cpumask(hctx->cpumask, &data);
if (!rq)
goto out_queue_exit;
return rq;
diff --git a/block/blk-mq.h b/block/blk-mq.h
index e7d1da4b1f731..82921b30b6afa 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -155,6 +155,9 @@ struct blk_mq_alloc_data {
/* input & output parameter */
struct blk_mq_ctx *ctx;
struct blk_mq_hw_ctx *hctx;
+
+ /* output parameter for __blk_mq_alloc_request_cb */
+ struct request *rq;
};
static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
--
2.26.2
