lkml.org 
[lkml]   [2007]   [Oct]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] synchronize_irq needs a barrier
From
Date
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();
}

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-18 03:29    [W:0.090 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site