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SubjectRe: Re: [PATCH 1/2] [SCSI] pm8001: Fix bogus interrupt state flag issue.
Thanks Mark for look into this.You're right. The change for task_state_lock is not right.
Sorry for not look carefully about the change.



--------------
jack_wang
>NAK
>In the fragment below, the 'spin_lock_irqsave(&t->task_state_lock, flags);' is 100% legitimate. The change you did was not inert, and result in the IRQ being disabled upon exit should a SAS_TASK_STATE_ABORTED task state condition occur.
>
>I propose (annotated below) you leave the flags automatic variable, but uninitialized. The changes surrounding spin_*lock_irq*(&pm8001_ha->lock, flags) are OK, but revert back the changes surrounding the spin_*lock_irq*(&t->task->state_lock,flags) so that lock would be properly nested.
>
>To be pedantic, and to be more correct, this code should have spawned a work queue task to perform the t->task_done(t) operation in a separate thread rather than inline and precariously unlocked; but that would be beyond the scope of these changes and should be left for future work to decide if it is even necessary. Not sure how such a change would affect performance (using the work queue) ... so I am 'afraid' of pushing such a change in any case given the relatively reliable operation of this driver (and the dynamic nature of the changes Dan is making to the SATA side of things for instance ;-} ).
>
>I am sorry for taking so long to get to the task of reviewing this (and the previous) code. I look forward to your comments.
>
>Sincerely -- Mark Salyzyn
>
>On Feb 26, 2012, at 8:33 AM, santosh nayak wrote:
>
>> @@ -2207,7 +2206,6 @@ mpi_sata_completion(struct pm8001_hba_info *pm8001_ha, void *piomb)
>> static void mpi_sata_event(struct pm8001_hba_info *pm8001_ha , void *piomb)
>> {
>> struct sas_task *t;
>> - unsigned long flags = 0;
>MGS> unsigned long flags;
>> struct task_status_struct *ts;
>> struct pm8001_ccb_info *ccb;
>> struct pm8001_device *pm8001_dev;
>> @@ -2287,9 +2285,9 @@ static void mpi_sata_event(struct pm8001_hba_info *pm8001_ha , void *piomb)
>> ts->stat = SAS_QUEUE_FULL;
>> pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
>> mb();/*ditto*/
>> - spin_unlock_irqrestore(&pm8001_ha->lock, flags);
>> + spin_unlock_irq(&pm8001_ha->lock);
>> t->task_done(t);
>> - spin_lock_irqsave(&pm8001_ha->lock, flags);
>> + spin_lock_irq(&pm8001_ha->lock);
>> return;
>> }
>> break;
>> @@ -2387,31 +2385,31 @@ static void mpi_sata_event(struct pm8001_hba_info *pm8001_ha , void *piomb)
>> ts->stat = SAS_OPEN_TO;
>> break;
>> }
>> - spin_lock_irqsave(&t->task_state_lock, flags);
>> + spin_lock_irq(&t->task_state_lock);
>MGS> spin_lock_irqsave(&t->task_state_lock, flags);
>> t->task_state_flags &= ~SAS_TASK_STATE_PENDING;
>> t->task_state_flags &= ~SAS_TASK_AT_INITIATOR;
>> t->task_state_flags |= SAS_TASK_STATE_DONE;
>> if (unlikely((t->task_state_flags & SAS_TASK_STATE_ABORTED))) {
>> - spin_unlock_irqrestore(&t->task_state_lock, flags);
>> + spin_unlock_irq(&t->task_state_lock);
>MGS> spin_unlock_irqrestore(&t->task_state_lock, flags);
>> PM8001_FAIL_DBG(pm8001_ha,
>> pm8001_printk("task 0x%p done with io_status 0x%x"
>> " resp 0x%x stat 0x%x but aborted by upper layer!\n",
>> t, event, ts->resp, ts->stat));
>> pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
>> } else if (t->uldd_task) {
>> - spin_unlock_irqrestore(&t->task_state_lock, flags);
>> + spin_unlock_irq(&t->task_state_lock);
>> pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
>> mb();/* ditto */
>> - spin_unlock_irqrestore(&pm8001_ha->lock, flags);
>> + spin_unlock_irq(&pm8001_ha->lock);
>> t->task_done(t);
>> - spin_lock_irqsave(&pm8001_ha->lock, flags);
>> + spin_lock_irq(&pm8001_ha->lock);
>> } else if (!t->uldd_task) {
>> - spin_unlock_irqrestore(&t->task_state_lock, flags);
>> + spin_unlock_irq(&t->task_state_lock);
>> pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
>> mb();/*ditto*/
>> - spin_unlock_irqrestore(&pm8001_ha->lock, flags);
>> + spin_unlock_irq(&pm8001_ha->lock);
>> t->task_done(t);
>> - spin_lock_irqsave(&pm8001_ha->lock, flags);
>> + spin_lock_irq(&pm8001_ha->lock);
>> }
>> }
>
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