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SubjectRe: [PATCH 1/2] [SCSI] pm8001: Fix bogus interrupt state flag issue.
On Sun, Feb 26, 2012 at 07:03:30PM +0530, santosh nayak wrote:
> From: Santosh Nayak <santoshprasadnayak@gmail.com>
>
> Static checker is giving following warning:
> " error: calling 'spin_unlock_irqrestore()' with bogus flags"
>
> The code flow is as shown below:
> process_oq() --> process_one_iomb --> mpi_sata_completion
>
> In 'mpi_sata_completion'
> the first call for 'spin_unlock_irqrestore()' is with flags=0,
> which is as good as 'spin_unlock_irq()' ( unconditional interrupt
> enabling).
>
> So for better performance 'spin_unlock_irqrestore()' can be replaced
> with 'spin_unlock_irq()' and 'spin_lock_irqsave()' can be replaced by
> 'spin_lock_irq()'.
>

process_oq() is called from the interrupt handler pm8001_chip_isr()
with interrupts disabled.

drivers/scsi/pm8001/pm8001_hwi.c
4301 spin_lock_irqsave(&pm8001_ha->lock, flags);
4302 pm8001_chip_interrupt_disable(pm8001_ha);
4303 process_oq(pm8001_ha);
4304 pm8001_chip_interrupt_enable(pm8001_ha);
4305 spin_unlock_irqrestore(&pm8001_ha->lock, flags);

Probably we should just be doing a spin_lock() and spin_unlock()
without re-enabling the IRQs. Should we even be doing that in the
irq handler anyway?

regards,
dan carpenter

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