[PATCH] Make cpu_relax() imply barrier() on all arches
During the recent discussion of taking 'volatile' off of the spinlock, I noticed that while most arches #define cpu_relax() such that it implies barrier(), some arches define cpu_relax() to be empty. This patch changes the definition of cpu_relax() for frv, h8300, m68knommu, sh, sh64, v850 and xtensa from an empty while(0) to the compiler barrier(). Signed-off-by: Chase Venters <chase.venters@clientec.com> Acked-by: Arjan van de Ven <arjan@Linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Linus Torvalds

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@@ -21,6 +21,7 @@
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*/
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#define current_text_addr() ({ __label__ _l; _l: &&_l;})
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#include <linux/compiler.h>
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#include <linux/linkage.h>
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#include <asm/sections.h>
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#include <asm/segment.h>
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@@ -139,7 +140,7 @@ unsigned long get_wchan(struct task_struct *p);
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extern struct task_struct *alloc_task_struct(void);
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extern void free_task_struct(struct task_struct *p);
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#define cpu_relax() do { } while (0)
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#define cpu_relax() barrier()
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/* data cache prefetch */
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#define ARCH_HAS_PREFETCH
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