On 7/31/25 3:20 PM, Hannes Reinecke wrote:
> On 7/30/25 10:22, Yu Kuai wrote:
>> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>>
>> Replace the internal spinlock 'dd->lock' with the new spinlock in
>> elevator_queue, there are no functional changes.
>>
>> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
>> ---
>> block/mq-deadline.c | 58 +++++++++++++++++++++------------------------
>> 1 file changed, 27 insertions(+), 31 deletions(-)
>>
>> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
>> index 9ab6c6256695..2054c023e855 100644
>> --- a/block/mq-deadline.c
>> +++ b/block/mq-deadline.c
>> @@ -101,7 +101,7 @@ struct deadline_data {
>> u32 async_depth;
>> int prio_aging_expire;
>> - spinlock_t lock;
>> + spinlock_t *lock;
>> };
>> /* Maps an I/O priority class to a deadline scheduler priority. */
>> @@ -213,7 +213,7 @@ static void dd_merged_requests(struct request_queue *q,
>> struct request *req,
>> const u8 ioprio_class = dd_rq_ioclass(next);
>> const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
>> - lockdep_assert_held(&dd->lock);
>> + lockdep_assert_held(dd->lock);
>> dd->per_prio[prio].stats.merged++;
>> @@ -253,7 +253,7 @@ static u32 dd_queued(struct deadline_data *dd, enum
>> dd_prio prio)
>> {
>> const struct io_stats_per_prio *stats = &dd->per_prio[prio].stats;
>> - lockdep_assert_held(&dd->lock);
>> + lockdep_assert_held(dd->lock);
>> return stats->inserted - atomic_read(&stats->completed);
>> }
>> @@ -323,7 +323,7 @@ static struct request *__dd_dispatch_request(struct
>> deadline_data *dd,
>> enum dd_prio prio;
>> u8 ioprio_class;
>> - lockdep_assert_held(&dd->lock);
>> + lockdep_assert_held(dd->lock);
>> if (!list_empty(&per_prio->dispatch)) {
>> rq = list_first_entry(&per_prio->dispatch, struct request,
>> @@ -434,7 +434,7 @@ static struct request
>> *dd_dispatch_prio_aged_requests(struct deadline_data *dd,
>> enum dd_prio prio;
>> int prio_cnt;
>> - lockdep_assert_held(&dd->lock);
>> + lockdep_assert_held(dd->lock);
>> prio_cnt = !!dd_queued(dd, DD_RT_PRIO) + !!dd_queued(dd, DD_BE_PRIO) +
>> !!dd_queued(dd, DD_IDLE_PRIO);
>> @@ -466,10 +466,9 @@ static struct request *dd_dispatch_request(struct
>> blk_mq_hw_ctx *hctx)
>> struct request *rq;
>> enum dd_prio prio;
>> - spin_lock(&dd->lock);
>> rq = dd_dispatch_prio_aged_requests(dd, now);
>> if (rq)
>> - goto unlock;
>> + return rq;
>> /*
>> * Next, dispatch requests in priority order. Ignore lower priority
>> @@ -481,9 +480,6 @@ static struct request *dd_dispatch_request(struct
>> blk_mq_hw_ctx *hctx)
>> break;
>> }
>> -unlock:
>> - spin_unlock(&dd->lock);
>> -
>> return rq;
>> }
>> @@ -538,9 +534,9 @@ static void dd_exit_sched(struct elevator_queue *e)
>> WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_READ]));
>> WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_WRITE]));
>> - spin_lock(&dd->lock);
>> + spin_lock(dd->lock);
>> queued = dd_queued(dd, prio);
>> - spin_unlock(&dd->lock);
>> + spin_unlock(dd->lock);
>> WARN_ONCE(queued != 0,
>> "statistics for priority %d: i %u m %u d %u c %u\n",
>
> Do you still need 'dd->lock'? Can't you just refer to the lock from the
> elevator_queue structure directly?
Indeed. Little inline helpers for locking/unlocking q->elevator->lock would be
nice.
--
Damien Le Moal
Western Digital Research
