The patch titled
percpu: fix DEBUG_PREEMPT per_cpu checking
has been added to the -mm tree. Its filename is
percpu-fix-debug_preempt-per_cpu-checking.patch
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------------------------------------------------------
Subject: percpu: fix DEBUG_PREEMPT per_cpu checking
From: Hugh Dickins <hugh@xxxxxxxxxxx>
Recent percpu changes have broken CONFIG_DEBUG_PREEMPT's per_cpu checking
on several architectures. On s390, sparc64 and x86 it's been weakened to
not checking at all; whereas on powerpc64 it's become too strict, issuing
warnings from __raw_get_cpu_var in io_schedule and init_timer for example.
Fix this by weakening powerpc's __my_cpu_offset to use the non-checking
local_paca instead of get_paca (which itself contains such a check); and
strengthening the generic my_cpu_offset to go the old slow way via
smp_processor_id when CONFIG_DEBUG_PREEMPT (debug_smp_processor_id is where
all the knowledge of what's correct when lives).
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/asm-generic/percpu.h | 2 ++
include/asm-powerpc/percpu.h | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff -puN include/asm-generic/percpu.h~percpu-fix-debug_preempt-per_cpu-checking include/asm-generic/percpu.h
--- a/include/asm-generic/percpu.h~percpu-fix-debug_preempt-per_cpu-checking
+++ a/include/asm-generic/percpu.h
@@ -32,6 +32,8 @@ extern unsigned long __per_cpu_offset[NR
*/
#ifndef __my_cpu_offset
#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
+#endif
+#ifdef CONFIG_DEBUG_PREEMPT
#define my_cpu_offset per_cpu_offset(smp_processor_id())
#else
#define my_cpu_offset __my_cpu_offset
diff -puN include/asm-powerpc/percpu.h~percpu-fix-debug_preempt-per_cpu-checking include/asm-powerpc/percpu.h
--- a/include/asm-powerpc/percpu.h~percpu-fix-debug_preempt-per_cpu-checking
+++ a/include/asm-powerpc/percpu.h
@@ -13,7 +13,7 @@
#include <asm/paca.h>
#define __per_cpu_offset(cpu) (paca[cpu].data_offset)
-#define __my_cpu_offset get_paca()->data_offset
+#define __my_cpu_offset local_paca->data_offset
#define per_cpu_offset(x) (__per_cpu_offset(x))
#endif /* CONFIG_SMP */
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
origin.patch
git-unionfs.patch
git-x86.patch
percpu-fix-debug_preempt-per_cpu-checking.patch
r-o-bind-mounts-track-number-of-mount-writers.patch
procfs-task-exe-symlink.patch
procfs-task-exe-symlink-fix.patch
prio_tree-debugging-patch.patch
-
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