Re: [PATCH] Remove deprecated IRQF_DISABLED flag entirely

Hannes Reinecke
2015-03-05T13:11:31Z

On 03/05/2015 01:59 PM, Valentin Rothberg wrote:
> The IRQF_DISABLED is a NOOP and has been scheduled for removal since
> Linux v2.6.36 by commit 6932bf37bed4 ("genirq: Remove IRQF_DISABLED from
> core code").
>
> According to commit e58aa3d2d0cc ("genirq: Run irq handlers with
> interrupts disabled") running IRQ handlers with interrupts enabled can
> cause stack overflows when the interrupt line of the issuing device is
> still active.
>
> This patch ends the grace period for IRQF_DISABLED (i.e., SA_INTERRUPT
> in older versions of Linux) and removes the definition and all remaining
> usages of this flag.
>
> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
> ---
> The bigger hunk in Documentation/scsi/ncr53c8xx.txt is removed entirely
> as IRQF_DISABLED is gone now; the usage in older kernel versions
> (including the old SA_INTERRUPT flag) should be discouraged. The
> trouble of using IRQF_SHARED is a general problem and not specific to
> any driver.
>
> I left the reference in Documentation/PCI/MSI-HOWTO.txt untouched since
> it has already been removed in linux-next by commit b0e1ee8e1405
> ("MSI-HOWTO.txt: remove reference on IRQF_DISABLED").
>
> All remaining references are changelogs that I suggest to keep.

While you're at it: having '0x0' as a value for the irq flags looks
a bit silly, and makes you wonder what the parameter is for.

I would rather like to have

#define IRQF_NONE 0x0

and use it for these cases.
That way the scope of that parameter is clear.

Cheers,

Hannes
--
Dr. Hannes Reinecke zSeries & Storage
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