Re: [PATCH RFC v3 21/22] scsi: libsas: Queue internal abort commands as requests

[John Garry <john.g.garry@xxxxxxxxxx>]

On 29/10/2022 02:15, chenxiang (M) wrote:
> Hi John,
>
> For internal abort commands, it allocates and deliver requests through 
> sdev->request_queue.
>
> Is it possible that we still need to send internal abort commands even 
> if sdev is freed?
>
> I  notices that in sas_destruct_devices, it calls sas_rphy_delete() to 
> remove target, and then call i->dft->lldd_dev_gone()
>
> which will call internal abort commands.

Good question. I did not properly check the removal path and, indeed, 
the sdev would be gone when we call lldd_dev_gone -> 
internal_task_abort_dev, so that should fail to execute.

However I do wonder why we really need to call internal_task_abort_dev 
in the lldd_dev_gone callback. At the point lldd_dev_gone is called all 
IO should be complete - indeed, it is now accounted for as requests 
associated with the sdev. If it is really required to be called (HW 
requirement?) then maybe it could be relocated to sdev/starget teardown 
callback.

Thanks,
John

> 在 2022/10/25 18:18, John Garry 写道:
> > Like what we did for SMP commands, send internal abort commands through
> > the block layer.
> >
> > At this point we can delete special handling in sas_task_abort() for SAS
> > "internal" commands, as every slow task now has a request associated.
> >
> > Function sas_task_internal_timedout() is no longer referenced, so delete
> > it.
> >
> > Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> > ---
> >   drivers/scsi/hisi_sas/hisi_sas_main.c | 36 +++++++++----------
> >   drivers/scsi/libsas/sas_expander.c    |  2 +-
> >   drivers/scsi/libsas/sas_init.c        | 12 +++++--
> >   drivers/scsi/libsas/sas_internal.h    |  3 +-
> >   drivers/scsi/libsas/sas_scsi_host.c   | 52 ++++++---------------------
> >   include/scsi/libsas.h                 |  1 -
> >   6 files changed, 38 insertions(+), 68 deletions(-)
> >
> > diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c 
> > b/drivers/scsi/hisi_sas/hisi_sas_main.c
> > index fe2752d24fe8..65475775c844 100644
> > --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
> > +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
> > @@ -465,7 +465,7 @@ static int hisi_sas_queue_command(struct sas_task 
> > *task, gfp_t gfp_flags)
> >       struct hisi_sas_port *port;
> >       struct hisi_hba *hisi_hba;
> >       struct hisi_sas_slot *slot;
> > -    struct request *rq = NULL;
> > +    struct request *rq;
> >       struct device *dev;
> >       int rc;
> > @@ -485,6 +485,21 @@ static int hisi_sas_queue_command(struct sas_task 
> > *task, gfp_t gfp_flags)
> >       hisi_hba = dev_to_hisi_hba(device);
> >       dev = hisi_hba->dev;
> > +    rq = sas_task_find_rq(task);
> > +    if (rq) {
> > +        unsigned int dq_index;
> > +        u32 blk_tag;
> > +
> > +        blk_tag = blk_mq_unique_tag(rq);
> > +        dq_index = blk_mq_unique_tag_to_hwq(blk_tag);
> > +        dq = &hisi_hba->dq[dq_index];
> > +    } else {
> > +        struct Scsi_Host *shost = hisi_hba->shost;
> > +        struct blk_mq_queue_map *qmap = 
> > &shost->tag_set.map[HCTX_TYPE_DEFAULT];
> > +        int queue = qmap->mq_map[raw_smp_processor_id()];
> > +
> > +        dq = &hisi_hba->dq[queue];
> > +    }
> >       switch (task->task_proto) {
> >       case SAS_PROTOCOL_SSP:
> > @@ -519,22 +534,6 @@ static int hisi_sas_queue_command(struct sas_task 
> > *task, gfp_t gfp_flags)
> >                   return -ECOMM;
> >           }
> > -
> > -        rq = sas_task_find_rq(task);
> > -        if (rq) {
> > -            unsigned int dq_index;
> > -            u32 blk_tag;
> > -
> > -            blk_tag = blk_mq_unique_tag(rq);
> > -            dq_index = blk_mq_unique_tag_to_hwq(blk_tag);
> > -            dq = &hisi_hba->dq[dq_index];
> > -        } else {
> > -            struct Scsi_Host *shost = hisi_hba->shost;
> > -            struct blk_mq_queue_map *qmap = 
> > &shost->tag_set.map[HCTX_TYPE_DEFAULT];
> > -            int queue = qmap->mq_map[raw_smp_processor_id()];
> > -
> > -            dq = &hisi_hba->dq[queue];
> > -        }
> >           break;
> >       case SAS_PROTOCOL_INTERNAL_ABORT:
> >           if (!hisi_hba->hw->prep_abort)
> > @@ -543,13 +542,10 @@ static int hisi_sas_queue_command(struct 
> > sas_task *task, gfp_t gfp_flags)
> >           if (test_bit(HISI_SAS_HW_FAULT_BIT, &hisi_hba->flags))
> >               return -EIO;
> > -        hisi_hba = dev_to_hisi_hba(device);
> > -
> >           if (unlikely(test_bit(HISI_SAS_REJECT_CMD_BIT, 
> > &hisi_hba->flags)))
> >               return -EINVAL;
> >           port = to_hisi_sas_port(sas_port);
> > -        dq = &hisi_hba->dq[task->abort_task.qid];
> >           break;
> >       default:
> >           dev_err(hisi_hba->dev, "task prep: unknown/unsupported proto 
> > (0x%x)\n",
> > diff --git a/drivers/scsi/libsas/sas_expander.c 
> > b/drivers/scsi/libsas/sas_expander.c
> > index cc41127ea5cc..e852f1565fe7 100644
> > --- a/drivers/scsi/libsas/sas_expander.c
> > +++ b/drivers/scsi/libsas/sas_expander.c
> > @@ -50,7 +50,7 @@ static int smp_execute_task_sg(struct domain_device 
> > *dev,
> >               break;
> >           }
> > -        task = sas_alloc_slow_task_rq(dev, GFP_KERNEL);
> > +        task = sas_alloc_slow_task_rq(dev, GFP_KERNEL, -1U);
> >           if (!task) {
> >               res = -ENOMEM;
> >               break;
> > diff --git a/drivers/scsi/libsas/sas_init.c 
> > b/drivers/scsi/libsas/sas_init.c
> > index 5f9e71a54799..c3f602bd2c4c 100644
> > --- a/drivers/scsi/libsas/sas_init.c
> > +++ b/drivers/scsi/libsas/sas_init.c
> > @@ -56,7 +56,7 @@ struct sas_task *sas_alloc_slow_task(gfp_t flags)
> >       return task;
> >   }
> > -struct sas_task *sas_alloc_slow_task_rq(struct domain_device *device, 
> > gfp_t flags)
> > +struct sas_task *sas_alloc_slow_task_rq(struct domain_device *device, 
> > gfp_t flags, unsigned int qid)
> >   {
> >       struct sas_ha_struct *sas_ha = device->port->ha;
> >       struct Scsi_Host *shost = sas_ha->core.shost;
> > @@ -86,8 +86,14 @@ struct sas_task *sas_alloc_slow_task_rq(struct 
> > domain_device *device, gfp_t flag
> >       task->dev = device;
> >       task->task_done = sas_task_complete_internal;
> > -    rq = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN,
> > -                BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
> > +    if (qid == -1U) {
> > +        rq = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN,
> > +                    BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
> > +    } else {
> > +        rq = scsi_alloc_request_hwq(sdev->request_queue, REQ_OP_DRV_IN,
> > +                    BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT,
> > +                    qid);
> > +    }
> >       if (IS_ERR(rq)) {
> >           sas_free_task(task);
> >           return NULL;
> > diff --git a/drivers/scsi/libsas/sas_internal.h 
> > b/drivers/scsi/libsas/sas_internal.h
> > index 9b58948c57c2..af4a4bf88830 100644
> > --- a/drivers/scsi/libsas/sas_internal.h
> > +++ b/drivers/scsi/libsas/sas_internal.h
> > @@ -54,7 +54,8 @@ void sas_free_event(struct asd_sas_event *event);
> >   struct sas_task *sas_alloc_task(gfp_t flags);
> >   struct sas_task *sas_alloc_slow_task(gfp_t flags);
> > -struct sas_task *sas_alloc_slow_task_rq(struct domain_device *device, 
> > gfp_t flags);
> > +struct sas_task *sas_alloc_slow_task_rq(struct domain_device *device, 
> > gfp_t flags,
> > +                      unsigned int qid);
> >   void sas_free_task(struct sas_task *task);
> >   int  sas_register_ports(struct sas_ha_struct *sas_ha);
> > diff --git a/drivers/scsi/libsas/sas_scsi_host.c 
> > b/drivers/scsi/libsas/sas_scsi_host.c
> > index e6ee8dd56a45..a93e019a7dbf 100644
> > --- a/drivers/scsi/libsas/sas_scsi_host.c
> > +++ b/drivers/scsi/libsas/sas_scsi_host.c
> > @@ -920,23 +920,6 @@ void sas_task_complete_internal(struct sas_task 
> > *task)
> >       scsi_done(scmd);
> >   }
> > -void sas_task_internal_timedout(struct timer_list *t)
> > -{
> > -    struct sas_task_slow *slow = from_timer(slow, t, timer);
> > -    struct sas_task *task = slow->task;
> > -    bool is_completed = true;
> > -    unsigned long flags;
> > -
> > -    spin_lock_irqsave(&task->task_state_lock, flags);
> > -    if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
> > -        task->task_state_flags |= SAS_TASK_STATE_ABORTED;
> > -        is_completed = false;
> > -    }
> > -    spin_unlock_irqrestore(&task->task_state_lock, flags);
> > -
> > -    if (!is_completed)
> > -        complete(&task->slow_task->completion);
> > -}
> >   enum blk_eh_timer_return sas_internal_timeout(struct scsi_cmnd *scmd)
> >   {
> >       struct sas_task *task = TO_SAS_TASK(scmd);
> > @@ -978,28 +961,23 @@ static int sas_execute_internal_abort(struct 
> > domain_device *device,
> >       int res, retry;
> >       for (retry = 0; retry < TASK_RETRY; retry++) {
> > -        task = sas_alloc_slow_task(GFP_KERNEL);
> > +        struct request *rq;
> > +
> > +        task = sas_alloc_slow_task_rq(device, GFP_KERNEL, qid);
> >           if (!task)
> >               return -ENOMEM;
> >           task->dev = device;
> >           task->task_proto = SAS_PROTOCOL_INTERNAL_ABORT;
> > -        task->task_done = sas_task_internal_done;
> > -        task->slow_task->timer.function = sas_task_internal_timedout;
> > -        task->slow_task->timer.expires = jiffies + TASK_TIMEOUT;
> > -        add_timer(&task->slow_task->timer);
> > +        task->task_done = sas_task_complete_internal;
> >           task->abort_task.tag = tag;
> >           task->abort_task.type = type;
> > -        task->abort_task.qid = qid;
> > -        res = i->dft->lldd_execute_task(task, GFP_KERNEL);
> > -        if (res) {
> > -            del_timer_sync(&task->slow_task->timer);
> > -            pr_err("Executing internal abort failed %016llx (%d)\n",
> > -                   SAS_ADDR(device->sas_addr), res);
> > -            break;
> > -        }
> > +        rq = scsi_cmd_to_rq(task->uldd_task);
> > +        rq->timeout = TASK_TIMEOUT;
> > +
> > +        blk_execute_rq_nowait(rq, true);
> >           wait_for_completion(&task->slow_task->completion);
> >           res = TMF_RESP_FUNC_FAILED;
> > @@ -1069,7 +1047,7 @@ int sas_execute_tmf(struct domain_device 
> > *device, void *parameter,
> >       for (retry = 0; retry < TASK_RETRY; retry++) {
> >           struct request *rq;
> > -        task = sas_alloc_slow_task_rq(device, GFP_KERNEL);
> > +        task = sas_alloc_slow_task_rq(device, GFP_KERNEL, -1U);
> >           if (!task)
> >               return -ENOMEM;
> > @@ -1251,17 +1229,7 @@ void sas_task_abort(struct sas_task *task)
> >   {
> >       struct scsi_cmnd *sc = task->uldd_task;
> > -    /* Escape for libsas internal commands */
> > -    if (!sc) {
> > -        struct sas_task_slow *slow = task->slow_task;
> > -
> > -        if (!slow)
> > -            return;
> > -        if (!del_timer(&slow->timer))
> > -            return;
> > -        slow->timer.function(&slow->timer);
> > -        return;
> > -    }
> > +    WARN_ON_ONCE(!sc);
> >       if (dev_is_sata(task->dev) && !task->slow_task)
> >           sas_ata_task_abort(task);
> > diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
> > index f02156ccd376..60543d8b01d4 100644
> > --- a/include/scsi/libsas.h
> > +++ b/include/scsi/libsas.h
> > @@ -565,7 +565,6 @@ enum sas_internal_abort {
> >   struct sas_internal_abort_task {
> >       enum sas_internal_abort type;
> > -    unsigned int qid;
> >       u16 tag;
> >   };