The first is not called, just implement a interface, just reserved.
Thanks anyway.
Jack
>
> Thanks Jack for your response.
>
> 'process_oq' is called at two places.
>
>
> pm8001_8001_dispatch = {
> .......
>
> .isr = pm8001_chip_isr --> process_oq, // 1st
> place
> .isr_process_oq = process_oq, //
> 2nd place
> .....
> }
>
> regards
> santosh
>
> On Mon, Feb 27, 2012 at 10:18 AM, Jack Wang <jack_wang@xxxxxxxxx> wrote:
> > Infact , process_oq is only called in pm8001_chip_isr, but this patch
looks
> > OK for me. Move down the lock to process_oq is OK.
> >
> > Thanks for fix.
> > Acked-by : Jack Wang <jack_wang@xxxxxxxxx>
> >
> >> From: Santosh Nayak <santoshprasadnayak@xxxxxxxxx>
> >>
> >> There is a possble racing scenario.
> >>
> >> 'process_oq' is called by two routines, as shown below.
> >>
> >> pm8001_8001_dispatch = {
> >> .......
> >>
> >> .isr = pm8001_chip_isr --> process_oq,// A
> >> .isr_process_oq = process_oq, // B
> >> .....
> >> }
> >>
> >> process_oq() --> process_one_iomb() --> mpi_sata_completion()
> >>
> >> In 'mpi_sata_completion', "pm8001_ha->lock" is first released.
> >> It means lock is taken before, which is true for
> >> the context A, as 'pm8001_ha->lock' is taken in 'pm8001_chip_isr()'
> >>
> >> But for context B there is no lock taken before and pm8001_ha->lock
> >> is unlocked in 'mpi_sata_completion()'. This may unlock the lock
> >> taken in context A. Possible racing ??
> >>
> >> If 'pm8001_ha->lock' is taken in 'process_oq()' instead of
> >> 'pm8001_chip_isr' then the above issue can be avoided.
> >>
> >> Signed-off-by: Santosh Nayak <santoshprasadnayak@xxxxxxxxx>
> >> ---
> >> drivers/scsi/pm8001/pm8001_hwi.c | 6 +++---
> >> 1 files changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/scsi/pm8001/pm8001_hwi.c
> >> b/drivers/scsi/pm8001/pm8001_hwi.c
> >> index 838e3e2..6d9973b 100644
> >> --- a/drivers/scsi/pm8001/pm8001_hwi.c
> >> +++ b/drivers/scsi/pm8001/pm8001_hwi.c
> >> @@ -3663,7 +3663,9 @@ static int process_oq(struct pm8001_hba_info
> > *pm8001_ha)
> >> void *pMsg1 = NULL;
> >> u8 uninitialized_var(bc);
> >> u32 ret = MPI_IO_STATUS_FAIL;
> >> + unsigned long flags;
> >>
> >> + spin_lock_irqsave(&pm8001_ha->lock, flags);
> >> circularQ = &pm8001_ha->outbnd_q_tbl[0];
> >> do {
> >> ret = mpi_msg_consume(pm8001_ha, circularQ, &pMsg1, &bc);
> >> @@ -3682,6 +3684,7 @@ static int process_oq(struct pm8001_hba_info
> > *pm8001_ha)
> >> break;
> >> }
> >> } while (1);
> >> + spin_unlock_irqrestore(&pm8001_ha->lock, flags);
> >> return ret;
> >> }
> >>
> >> @@ -4087,12 +4090,9 @@ static u32 pm8001_chip_is_our_interupt(struct
> >> pm8001_hba_info *pm8001_ha)
> >> static irqreturn_t
> >> pm8001_chip_isr(struct pm8001_hba_info *pm8001_ha)
> >> {
> >> - unsigned long flags;
> >> - spin_lock_irqsave(&pm8001_ha->lock, flags);
> >> pm8001_chip_interrupt_disable(pm8001_ha);
> >> process_oq(pm8001_ha);
> >> pm8001_chip_interrupt_enable(pm8001_ha);
> >> - spin_unlock_irqrestore(&pm8001_ha->lock, flags);
> >> return IRQ_HANDLED;
> >> }
> >>
> >> --
> >> 1.7.4.4
> >>
> >> --
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> >
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