Re: [PATCH] powerpc: Fix spin_event_timeout() to be robust over context switches

From: Timur Tabi
Date: Tue Jun 30 2009 - 11:03:00 EST


On Mon, Jun 29, 2009 at 6:40 PM, Grant Likely<grant.likely@xxxxxxxxxxxx> wrote:
> From: Grant Likely <grant.likely@xxxxxxxxxxxx>
>
> Current implementation of spin_event_timeout can be interrupted by an
> IRQ or context switch after testing the condition, but before checking
> the timeout.  This can cause the loop to report a timeout when the
> condition actually became true in the middle.
>
> This patch adds one final check of the condition upon exit of the loop
> if the last test of the condition was still false.
>
> Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx>

Acked-by: Timur Tabi <timur@xxxxxxxxxxxxx>

Ben, please pick this up for the next rc of 2.6.31.

--
Timur Tabi
Linux kernel developer at Freescale
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