Re: [PATCH v2 1/1] blk-mq: Inline request status checkers

[Jens Axboe]

On 9/30/19 2:12 PM, Pavel Begunkov wrote:
> On 30/09/2019 22:53, Bart Van Assche wrote:
>> On 9/30/19 12:43 PM, Pavel Begunkov (Silence) wrote:
>>> @@ -282,7 +282,7 @@ static bool bt_tags_iter(struct sbitmap *bitmap, 
>>> unsigned int bitnr, void *data)
>>>  * test and set the bit before assining ->rqs[].
>>>  */
>>> rq = tags->rqs[bitnr];
>>> -   if (rq && blk_mq_request_started(rq))
>>> +   if (rq && blk_mq_rq_state(rq) != MQ_RQ_IDLE)
>>> return iter_data->fn(rq, iter_data->data, reserved);
>>>   
>>> return true>
>>> @@ -360,7 +360,7 @@ static bool blk_mq_tagset_count_completed_rqs(struct 
>>> request *rq,
>>>   {
>>> unsigned *count = data;
>>>   
>>> -   if (blk_mq_request_completed(rq))
>>> +   if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
>>> (*count)++;
>>> return true;
>>>   }
>>
>> Changes like the above significantly reduce readability of the code in
>> the block layer core. I don't like this. I think this patch is a step
>> backwards instead of a step forwards.
> 
> Yep, looks too bulky.
> 
> Jens, could you consider the first version?

Yes, first one is fine, I have applied it. Thanks.

-- 
Jens Axboe

[PATCH v2 1/1] blk-mq: Inline request status checkers

[Pavel Begunkov (Silence)]

From: Pavel Begunkov 

blk_mq_request_completed() and blk_mq_request_started() are
short, inline it.

v2: by Christoph suggestion inline them by hand

Signed-off-by: Pavel Begunkov 
---
 block/blk-mq-tag.c   |  4 ++--
 block/blk-mq.c   | 14 +-
 block/blk-mq.h   |  9 -
 drivers/block/nbd.c  |  2 +-
 drivers/nvme/host/core.c |  2 +-
 include/linux/blk-mq.h   | 10 --
 6 files changed, 13 insertions(+), 28 deletions(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 008388e82b5c..32d63b607391 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -282,7 +282,7 @@ static bool bt_tags_iter(struct sbitmap *bitmap, unsigned 
int bitnr, void *data)
 * test and set the bit before assining ->rqs[].
 */
rq = tags->rqs[bitnr];
-   if (rq && blk_mq_request_started(rq))
+   if (rq && blk_mq_rq_state(rq) != MQ_RQ_IDLE)
return iter_data->fn(rq, iter_data->data, reserved);
 
return true;
@@ -360,7 +360,7 @@ static bool blk_mq_tagset_count_completed_rqs(struct 
request *rq,
 {
unsigned *count = data;
 
-   if (blk_mq_request_completed(rq))
+   if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
(*count)++;
return true;
 }
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 29275f5a996f..a30f108d96be 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -663,18 +663,6 @@ bool blk_mq_complete_request(struct request *rq)
 }
 EXPORT_SYMBOL(blk_mq_complete_request);
 
-int blk_mq_request_started(struct request *rq)
-{
-   return blk_mq_rq_state(rq) != MQ_RQ_IDLE;
-}
-EXPORT_SYMBOL_GPL(blk_mq_request_started);
-
-int blk_mq_request_completed(struct request *rq)
-{
-   return blk_mq_rq_state(rq) == MQ_RQ_COMPLETE;
-}
-EXPORT_SYMBOL_GPL(blk_mq_request_completed);
-
 void blk_mq_start_request(struct request *rq)
 {
struct request_queue *q = rq->q;
@@ -718,7 +706,7 @@ static void __blk_mq_requeue_request(struct request *rq)
trace_block_rq_requeue(q, rq);
rq_qos_requeue(q, rq);
 
-   if (blk_mq_request_started(rq)) {
+   if (blk_mq_rq_state(rq) != MQ_RQ_IDLE) {
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
rq->rq_flags &= ~RQF_TIMED_OUT;
if (q->dma_drain_size && blk_rq_bytes(rq))
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 32c62c64e6c2..eaaca8fc1c28 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -128,15 +128,6 @@ extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx 
*hctx);
 
 void blk_mq_release(struct request_queue *q);
 
-/**
- * blk_mq_rq_state() - read the current MQ_RQ_* state of a request
- * @rq: target request.
- */
-static inline enum mq_rq_state blk_mq_rq_state(struct request *rq)
-{
-   return READ_ONCE(rq->state);
-}
-
 static inline struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
   unsigned int cpu)
 {
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index ac07e8c94c79..71a13a65c9d1 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -696,7 +696,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device 
*nbd, int index)
if (hwq < nbd->tag_set.nr_hw_queues)
req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
   blk_mq_unique_tag_to_tag(tag));
-   if (!req || !blk_mq_request_started(req)) {
+   if (!req || !blk_mq_rq_state(req) != MQ_RQ_IDLE) {
dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
tag, req);
return ERR_PTR(-ENOENT);
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 108f60b46804..3a54677dc5ad 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -292,7 +292,7 @@ bool nvme_cancel_request(struct request *req, void *data, 
bool reserved)
"Cancelling I/O %d", req->tag);
 
/* don't abort one completed request */
-   if (blk_mq_request_completed(req))
+   if (blk_mq_rq_state(req) == MQ_RQ_COMPLETE)
return true;
 
nvme_req(req)->status = NVME_SC_HOST_PATH_ERROR;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0bf056de5cc3..e993ce19a8ec 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -301,9 +301,15 @@ static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
 }
 
+/**
+ * blk_mq_rq_state() - read the current MQ_RQ_* state of a request
+ * @rq: target request.
+ */
+static inline enum mq_rq_state blk_mq_rq_state(struct request *rq)
+{
+   return READ_ONCE(rq->state);
+}
 
-int blk_mq_request_started(struct request *rq);
-int blk_mq_request_completed(struct request *rq);
 void blk_mq_start_request(struct request *rq);
 void blk_mq_end_request(struct request *rq, blk_status_t error);
 void __blk_mq_end_request(struct request *rq, blk_status_t error);
-- 
2.23.0

Re: [PATCH v2 1/1] blk-mq: Inline request status checkers

[Mike Snitzer]

On Mon, Sep 30 2019 at  3:53pm -0400,
Bart Van Assche  wrote:

> On 9/30/19 12:43 PM, Pavel Begunkov (Silence) wrote:
> > @@ -282,7 +282,7 @@ static bool bt_tags_iter(struct sbitmap *bitmap, 
> > unsigned int bitnr, void *data)
> >  * test and set the bit before assining ->rqs[].
> >  */
> > rq = tags->rqs[bitnr];
> > -   if (rq && blk_mq_request_started(rq))
> > +   if (rq && blk_mq_rq_state(rq) != MQ_RQ_IDLE)
> > return iter_data->fn(rq, iter_data->data, reserved);
> >  
> > return true>
> > @@ -360,7 +360,7 @@ static bool blk_mq_tagset_count_completed_rqs(struct 
> > request *rq,
> >  {
> > unsigned *count = data;
> >  
> > -   if (blk_mq_request_completed(rq))
> > +   if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
> > (*count)++;
> > return true;
> >  }
> 
> Changes like the above significantly reduce readability of the code in
> the block layer core. I don't like this. I think this patch is a step
> backwards instead of a step forwards.

I agree, not helpful.

Re: [PATCH v2 1/1] blk-mq: Inline request status checkers

[Pavel Begunkov]

On 30/09/2019 22:53, Bart Van Assche wrote:
> On 9/30/19 12:43 PM, Pavel Begunkov (Silence) wrote:
>> @@ -282,7 +282,7 @@ static bool bt_tags_iter(struct sbitmap *bitmap, 
>> unsigned int bitnr, void *data)
>>   * test and set the bit before assining ->rqs[].
>>   */
>>  rq = tags->rqs[bitnr];
>> -if (rq && blk_mq_request_started(rq))
>> +if (rq && blk_mq_rq_state(rq) != MQ_RQ_IDLE)
>>  return iter_data->fn(rq, iter_data->data, reserved);
>>  
>>  return true>
>> @@ -360,7 +360,7 @@ static bool blk_mq_tagset_count_completed_rqs(struct 
>> request *rq,
>>  {
>>  unsigned *count = data;
>>  
>> -if (blk_mq_request_completed(rq))
>> +if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
>>  (*count)++;
>>  return true;
>>  }
> 
> Changes like the above significantly reduce readability of the code in
> the block layer core. I don't like this. I think this patch is a step
> backwards instead of a step forwards.

Yep, looks too bulky.

Jens, could you consider the first version?


-- 
Yours sincerely,
Pavel Begunkov



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