Messages in this thread Patch in this message | | | Subject | [PATCH] synchronize_irq needs a barrier | From | Benjamin Herrenschmidt <> | Date | Thu, 18 Oct 2007 11:25:42 +1000 |
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synchronize_irq needs at the very least a compiler barrier and a read barrier on SMP, but there are enough cases around where a write barrier is also needed and it's not a hot path so I prefer using a full smp_mb() here.
It will degrade to a compiler barrier on !SMP.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> ---
Index: linux-work/kernel/irq/manage.c =================================================================== --- linux-work.orig/kernel/irq/manage.c 2007-10-18 11:22:16.000000000 +1000 +++ linux-work/kernel/irq/manage.c 2007-10-18 11:22:20.000000000 +1000 @@ -33,6 +33,7 @@ void synchronize_irq(unsigned int irq) if (irq >= NR_IRQS) return; + smp_mb(); while (desc->status & IRQ_INPROGRESS) cpu_relax(); }
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