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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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