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Subject[S390] Small barrier() and cpu_relax() cleanup.
From: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] Small barrier() and cpu_relax() cleanup.

cpu_relax() has barrier() semantics hence there is no need to use both
of them in conjunction in sclp_sync_wait(). Also change cpu_relax()
so it's more obvious that it has barrier semantics.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
drivers/s390/char/sclp.c | 1 -
include/asm-s390/processor.h | 5 ++---
2 files changed, 2 insertions(+), 4 deletions(-)
diff -urpN linux-2.6/drivers/s390/char/sclp.c linux-2.6-patched/drivers/s390/char/sclp.c
--- linux-2.6/drivers/s390/char/sclp.c 2007-01-26 17:27:59.000000000 +0100
+++ linux-2.6-patched/drivers/s390/char/sclp.c 2007-01-26 17:28:00.000000000 +0100
@@ -433,7 +433,6 @@ sclp_sync_wait(void)
get_clock() > timeout &&
del_timer(&sclp_request_timer))
sclp_request_timer.function(sclp_request_timer.data);
- barrier();
cpu_relax();
}
local_irq_disable();
diff -urpN linux-2.6/include/asm-s390/processor.h linux-2.6-patched/include/asm-s390/processor.h
--- linux-2.6/include/asm-s390/processor.h 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6-patched/include/asm-s390/processor.h 2007-01-26 17:28:00.000000000 +0100
@@ -201,9 +201,8 @@ unsigned long get_wchan(struct task_stru
static inline void cpu_relax(void)
{
if (MACHINE_HAS_DIAG44)
- asm volatile("diag 0,0,68" : : : "memory");
- else
- barrier();
+ asm volatile("diag 0,0,68");
+ barrier();
}

/*
-
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