Subject: + smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond.patch added to -mm tree
To: david.daney@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 06 Aug 2013 12:16:27 -0700
The patch titled
Subject: smp: quit unconditionally enabling irq in on_each_cpu_mask and on_each_cpu_cond
has been added to the -mm tree. Its filename is
smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond.patch
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------------------------------------------------------
From: David Daney <david.daney@xxxxxxxxxx>
Subject: smp: quit unconditionally enabling irq in on_each_cpu_mask and on_each_cpu_cond
As in f21afc25f9ed (:smp.h: Use local_irq_{save,restore}() in !SMP version
of on_each_cpu()"), we don't want to enable irqs if they are not already
enabled. There are currently no known problematical callers of these
functions, but since it is a known failure pattern, we preemptively fix
them.
Since they are not trivial functions, make them non-inline by moving them
to up.c. This also makes it so we don't have to fix #include dependancies
for preempt_{disable,enable}.
Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/smp.h | 62 ++++++++++--------------------------------
kernel/up.c | 39 ++++++++++++++++++++++++++
2 files changed, 55 insertions(+), 46 deletions(-)
diff -puN include/linux/smp.h~smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond include/linux/smp.h
--- a/include/linux/smp.h~smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond
+++ a/include/linux/smp.h
@@ -29,6 +29,22 @@ extern unsigned int total_cpus;
int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
int wait);
+/*
+ * Call a function on processors specified by mask, which might include
+ * the local one.
+ */
+void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
+ void *info, bool wait);
+
+/*
+ * Call a function on each processor for which the supplied function
+ * cond_func returns a positive value. This may include the local
+ * processor.
+ */
+void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
+ smp_call_func_t func, void *info, bool wait,
+ gfp_t gfp_flags);
+
#ifdef CONFIG_SMP
#include <linux/preempt.h>
@@ -101,22 +117,6 @@ static inline void call_function_init(vo
int on_each_cpu(smp_call_func_t func, void *info, int wait);
/*
- * Call a function on processors specified by mask, which might include
- * the local one.
- */
-void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
- void *info, bool wait);
-
-/*
- * Call a function on each processor for which the supplied function
- * cond_func returns a positive value. This may include the local
- * processor.
- */
-void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
- smp_call_func_t func, void *info, bool wait,
- gfp_t gfp_flags);
-
-/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
@@ -157,36 +157,6 @@ static inline void __smp_call_function_s
on_each_cpu(data->func, data->info, wait);
}
-/*
- * Note we still need to test the mask even for UP
- * because we actually can get an empty mask from
- * code that on SMP might call us without the local
- * CPU in the mask.
- */
-#define on_each_cpu_mask(mask, func, info, wait) \
- do { \
- if (cpumask_test_cpu(0, (mask))) { \
- local_irq_disable(); \
- (func)(info); \
- local_irq_enable(); \
- } \
- } while (0)
-/*
- * Preemption is disabled here to make sure the cond_func is called under the
- * same condtions in UP and SMP.
- */
-#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\
- do { \
- void *__info = (info); \
- preempt_disable(); \
- if ((cond_func)(0, __info)) { \
- local_irq_disable(); \
- (func)(__info); \
- local_irq_enable(); \
- } \
- preempt_enable(); \
- } while (0)
-
static inline void smp_send_reschedule(int cpu) { }
#define smp_prepare_boot_cpu() do {} while (0)
#define smp_call_function_many(mask, func, info, wait) \
diff -puN kernel/up.c~smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond kernel/up.c
--- a/kernel/up.c~smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond
+++ a/kernel/up.c
@@ -19,3 +19,42 @@ int smp_call_function_single(int cpu, vo
return 0;
}
EXPORT_SYMBOL(smp_call_function_single);
+
+/*
+ * Note we still need to test the mask even for UP
+ * because we actually can get an empty mask from
+ * code that on SMP might call us without the local
+ * CPU in the mask.
+ */
+void on_each_cpu_mask(const struct cpumask *mask,
+ smp_call_func_t func, void *info, bool wait)
+{
+ unsigned long flags;
+
+ if (cpumask_test_cpu(0, mask)) {
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
+ }
+}
+EXPORT_SYMBOL(on_each_cpu_mask);
+
+/*
+ * Preemption is disabled here to make sure the cond_func is called under the
+ * same condtions in UP and SMP.
+ */
+void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
+ smp_call_func_t func, void *info, bool wait,
+ gfp_t gfp_flags)
+{
+ unsigned long flags;
+
+ preempt_disable();
+ if (cond_func(0, info)) {
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
+ }
+ preempt_enable();
+}
+EXPORT_SYMBOL(on_each_cpu_cond);
_
Patches currently in -mm which might be from david.daney@xxxxxxxxxx are
revert-include-linux-smph-on_each_cpu-switch-back-to-a-macro.patch
smp-quit-unconditionally-enabling-irq-in-on_each_cpu_mask-and-on_each_cpu_cond.patch
upc-use-local_irq_saverestore-in-smp_call_function_single.patch
smph-move-smp-version-of-on_each_cpu-out-of-line.patch
linux-next.patch
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