2021-01-28 04:21:05

by Can Guo

[permalink] [raw]
Subject: [PATCH v3 1/3] scsi: ufs: Fix task management request completion timeout

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 <[email protected]>
---
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 8da75e6..c0c5925 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6395,6 +6395,7 @@ 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);

--
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2021-01-29 03:25:04

by Bart Van Assche

[permalink] [raw]
Subject: Re: [PATCH v3 1/3] scsi: ufs: Fix task management request completion timeout

On 1/27/21 8:16 PM, Can Guo 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 <[email protected]>
> ---
> 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 8da75e6..c0c5925 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6395,6 +6395,7 @@ 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);

blk_mq_start_request() not only marks a request as in-flight but also
starts a timer. However, no timeout handler has been defined in
ufshcd_tmf_ops. Should a timeout handler be defined in that data structure?

Thanks,

Bart.

2021-01-29 05:51:46

by Can Guo

[permalink] [raw]
Subject: Re: [PATCH v3 1/3] scsi: ufs: Fix task management request completion timeout

On 2021-01-29 11:22, Bart Van Assche wrote:
> On 1/27/21 8:16 PM, Can Guo 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 <[email protected]>
>> ---
>> 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 8da75e6..c0c5925 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -6395,6 +6395,7 @@ 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);
>
> blk_mq_start_request() not only marks a request as in-flight but also
> starts a timer. However, no timeout handler has been defined in
> ufshcd_tmf_ops. Should a timeout handler be defined in that data
> structure?
>

Block mq driver gives 30s as default timeout,
TMR timeout is 100ms in UFS driver. So we don't
need a timeout handler as of now.

Thanks,
Can Guo.

> Thanks,
>
> Bart.