diff mbox series

[v4,1/2] scsi: ufs: Fix task management request completion timeout

Message ID 1617166236-39908-2-git-send-email-cang@codeaurora.org (mailing list archive)
State Superseded
Headers show
Series Two fixes for task management request implementation | expand

Commit Message

Can Guo March 31, 2021, 4:50 a.m. UTC
ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn = ufshcd_compl_tm()),
but since blk_mq_tagset_busy_iter() only iterates over all reserved tags
and requests which are not in IDLE state, ufshcd_compl_tm() never gets a
chance to run. Thus, TMR always ends up with completion timeout. Fix it by
calling blk_mq_start_request() in  __ufshcd_issue_tm_cmd().

Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to allocate and free TMFs")

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Avri Altman March 31, 2021, 4:45 p.m. UTC | #1
> ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn =
> ufshcd_compl_tm()),
> but since blk_mq_tagset_busy_iter() only iterates over all reserved tags
> and requests which are not in IDLE state, ufshcd_compl_tm() never gets a
> chance to run. Thus, TMR always ends up with completion timeout. Fix it by
> calling blk_mq_start_request() in  __ufshcd_issue_tm_cmd().
> 
> Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to allocate and
> free TMFs")
> 
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
>  drivers/scsi/ufs/ufshcd.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index b49555fa..d4f8cb2 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6464,6 +6464,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba
> *hba,
> 
>         spin_lock_irqsave(host->host_lock, flags);
>         task_tag = hba->nutrs + free_slot;
> +       blk_mq_start_request(req);
Maybe just set req->state to MQ_RQ_IN_FLIGHT
Without all other irrelevant initializations such as add timeout etc.

Thanks,
Avri
> 
>         treq->req_header.dword_0 |= cpu_to_be32(task_tag);
> 
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
> Linux Foundation Collaborative Project.
Can Guo April 1, 2021, 2:57 a.m. UTC | #2
On 2021-04-01 00:45, Avri Altman wrote:
>> ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn =
>> ufshcd_compl_tm()),
>> but since blk_mq_tagset_busy_iter() only iterates over all reserved 
>> tags
>> and requests which are not in IDLE state, ufshcd_compl_tm() never gets 
>> a
>> chance to run. Thus, TMR always ends up with completion timeout. Fix 
>> it by
>> calling blk_mq_start_request() in  __ufshcd_issue_tm_cmd().
>> 
>> Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to 
>> allocate and
>> free TMFs")
>> 
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>>  drivers/scsi/ufs/ufshcd.c | 1 +
>>  1 file changed, 1 insertion(+)
>> 
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index b49555fa..d4f8cb2 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -6464,6 +6464,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba
>> *hba,
>> 
>>         spin_lock_irqsave(host->host_lock, flags);
>>         task_tag = hba->nutrs + free_slot;
>> +       blk_mq_start_request(req);
> Maybe just set req->state to MQ_RQ_IN_FLIGHT
> Without all other irrelevant initializations such as add timeout etc.
> 

I don't see any other drivers do that, is it appropriate
to call WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT) outside
block layer?

Thanks,
Can Guo.

> Thanks,
> Avri
>> 
>>         treq->req_header.dword_0 |= cpu_to_be32(task_tag);
>> 
>> --
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
>> Linux Foundation Collaborative Project.
Bart Van Assche April 1, 2021, 3:39 a.m. UTC | #3
On 3/31/21 9:45 AM, Avri Altman wrote:
>> ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn =
>> ufshcd_compl_tm()),
>> but since blk_mq_tagset_busy_iter() only iterates over all reserved tags
>> and requests which are not in IDLE state, ufshcd_compl_tm() never gets a
>> chance to run. Thus, TMR always ends up with completion timeout. Fix it by
>> calling blk_mq_start_request() in  __ufshcd_issue_tm_cmd().
>>
>> Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to allocate and
>> free TMFs")
>>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>>  drivers/scsi/ufs/ufshcd.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index b49555fa..d4f8cb2 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -6464,6 +6464,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba
>> *hba,
>>
>>         spin_lock_irqsave(host->host_lock, flags);
>>         task_tag = hba->nutrs + free_slot;
>> +       blk_mq_start_request(req);
> Maybe just set req->state to MQ_RQ_IN_FLIGHT
> Without all other irrelevant initializations such as add timeout etc.

Hmm ... I'm not sure that any of the actions performed by
blk_mq_start_request() are irrelevant in this context. Additionally, no
other block or SCSI driver sets MQ_RQ_IN_FLIGHT directly.

Thanks,

Bart.
diff mbox series

Patch

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b49555fa..d4f8cb2 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6464,6 +6464,7 @@  static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
 
 	spin_lock_irqsave(host->host_lock, flags);
 	task_tag = hba->nutrs + free_slot;
+	blk_mq_start_request(req);
 
 	treq->req_header.dword_0 |= cpu_to_be32(task_tag);