[patch 05/10] cpu topology: convert siblings_show macro to accept non-lvalues.

Martin Schwidefsky
2008-03-12T17:33:52Z

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From: Heiko Carstens <heiko.carstens@de.ibm.com>

The sibling cpu masks on s390 can change because of dynamic cpu
reconfiguration. Therefore accesses to these masks are protected with
a lock so there aren't concurrent read and write accesses at the same
time. cpumask_scnprint in define_siblings_show_func expects an lvalue
for the cpu mask which would make the locking down in the s390 arch
code pointless. To solve this change the topology code to save a
snapshot of the sibling cpu mask and use that for output purposes.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

drivers/base/topology.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

Index: quilt-2.6/drivers/base/topology.c
===================================================================
--- quilt-2.6.orig/drivers/base/topology.c
+++ quilt-2.6/drivers/base/topology.c
@@ -40,13 +40,16 @@ static ssize_t show_##name(struct sys_de
return sprintf(buf, "%d\n", topology_##name(cpu)); \
}

-#define define_siblings_show_func(name) \
-static ssize_t show_##name(struct sys_device *dev, char *buf) \
-{ \
- ssize_t len = -1; \
- unsigned int cpu = dev->id; \
- len = cpumask_scnprintf(buf, NR_CPUS+1, topology_##name(cpu)); \
- return (len + sprintf(buf + len, "\n")); \
+#define define_siblings_show_func(name) \
+static ssize_t show_##name(struct sys_device *dev, char *buf) \
+{ \
+ ssize_t len = -1; \
+ unsigned int cpu = dev->id; \
+ cpumask_t mask; \
+ \
+ mask = topology_##name(cpu); \
+ len = cpumask_scnprintf(buf, NR_CPUS + 1, mask); \
+ return len + sprintf(buf + len, "\n"); \
}

#ifdef topology_physical_package_id

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.