Messages in this thread Patch in this message | | | From | Grant Likely <> | Subject | [PATCH] powerpc: Fix spin_event_timeout() to be robust over context switches | Date | Mon, 29 Jun 2009 17:40:51 -0600 |
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From: Grant Likely <grant.likely@secretlab.ca>
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@secretlab.ca> ---
arch/powerpc/include/asm/delay.h | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/delay.h b/arch/powerpc/include/asm/delay.h index 1e2eb41..52e4d54 100644 --- a/arch/powerpc/include/asm/delay.h +++ b/arch/powerpc/include/asm/delay.h @@ -63,6 +63,8 @@ extern void udelay(unsigned long usecs); udelay(delay); \ else \ cpu_relax(); \ + if (!__ret) \ + __ret = (condition); \ __ret; \ })
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