[PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu

From: Zhang Yanfei
Date: Fri Dec 07 2012 - 00:42:49 EST


This removes the sparse warning:
arch/x86/kernel/crash.c:49:32: sparse: incompatible types in comparison expression (different address spaces)

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
---
arch/x86/include/asm/kexec.h | 4 +++-
arch/x86/kernel/crash.c | 4 ++--
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 28feeba..16882cd 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -163,7 +163,9 @@ struct kimage_arch {
};
#endif

-extern void (*crash_vmclear_loaded_vmcss)(void);
+extern void __rcu (*crash_vmclear_loaded_vmcss)(void);
+#define vmclear_func_rcu(vmclear_func) \
+ ((void (*)(void)) rcu_dereference(vmclear_func))

#endif /* __ASSEMBLY__ */

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 2f6b8e8..50ce1d6 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -38,7 +38,7 @@ int in_crash_kexec;
*
* protected by rcu.
*/
-void (*crash_vmclear_loaded_vmcss)(void) = NULL;
+void __rcu (*crash_vmclear_loaded_vmcss)(void) = NULL;
EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);

static inline void cpu_crash_vmclear_loaded_vmcss(void)
@@ -46,7 +46,7 @@ static inline void cpu_crash_vmclear_loaded_vmcss(void)
void (*do_vmclear_operation)(void) = NULL;

rcu_read_lock();
- do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
+ do_vmclear_operation = vmclear_func_rcu(crash_vmclear_loaded_vmcss);
if (do_vmclear_operation)
do_vmclear_operation();
rcu_read_unlock();
--
1.7.1
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