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Subject[PATCH 07/11] smp: Consolidate the various smp_call_function_single() declensions
Date
__smp_call_function_single() and smp_call_function_single() share some
code that can be factorized: execute inline when the target is local,
check if the target is online, lock the csd, call generic_exec_single().

Lets move the common parts to generic_exec_single().

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
kernel/smp.c | 80 +++++++++++++++++++++++++++++-------------------------------
1 file changed, 39 insertions(+), 41 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 5ff14e3..64bb0d4 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -117,13 +117,43 @@ static void csd_unlock(struct call_single_data *csd)
csd->flags &= ~CSD_FLAG_LOCK;
}

+static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
+
/*
* Insert a previously allocated call_single_data element
* for execution on the given CPU. data must already have
* ->func, ->info, and ->flags set.
*/
-static void generic_exec_single(int cpu, struct call_single_data *csd, int wait)
+static int generic_exec_single(int cpu, struct call_single_data *csd,
+ smp_call_func_t func, void *info, int wait)
{
+ struct call_single_data csd_stack = { .flags = 0 };
+ unsigned long flags;
+
+
+ if (cpu == smp_processor_id()) {
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
+ return 0;
+ }
+
+
+ if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu))
+ return -ENXIO;
+
+
+ if (!csd) {
+ csd = &csd_stack;
+ if (!wait)
+ csd = &__get_cpu_var(csd_data);
+ }
+
+ csd_lock(csd);
+
+ csd->func = func;
+ csd->info = info;
+
if (wait)
csd->flags |= CSD_FLAG_WAIT;

@@ -143,6 +173,8 @@ static void generic_exec_single(int cpu, struct call_single_data *csd, int wait)

if (wait)
csd_lock_wait(csd);
+
+ return 0;
}

/*
@@ -168,8 +200,6 @@ void generic_smp_call_function_single_interrupt(void)
}
}

-static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
-
/*
* smp_call_function_single - Run a function on a specific CPU
* @func: The function to run. This must be fast and non-blocking.
@@ -181,12 +211,8 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
int wait)
{
- struct call_single_data d = {
- .flags = 0,
- };
- unsigned long flags;
int this_cpu;
- int err = 0;
+ int err;

/*
* prevent preemption and reschedule on another processor,
@@ -203,26 +229,7 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
&& !oops_in_progress);

- if (cpu == this_cpu) {
- local_irq_save(flags);
- func(info);
- local_irq_restore(flags);
- } else {
- if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
- struct call_single_data *csd = &d;
-
- if (!wait)
- csd = &__get_cpu_var(csd_data);
-
- csd_lock(csd);
-
- csd->func = func;
- csd->info = info;
- generic_exec_single(cpu, csd, wait);
- } else {
- err = -ENXIO; /* CPU not online */
- }
- }
+ err = generic_exec_single(cpu, NULL, func, info, wait);

put_cpu();

@@ -285,9 +292,8 @@ EXPORT_SYMBOL_GPL(smp_call_function_any);
*/
int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait)
{
- unsigned int this_cpu;
- unsigned long flags;
int err = 0;
+ int this_cpu;

this_cpu = get_cpu();
/*
@@ -296,20 +302,12 @@ int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait)
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
- WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled()
+ WARN_ON_ONCE(cpu_online(this_cpu) && wait && irqs_disabled()
&& !oops_in_progress);

- if (cpu == this_cpu) {
- local_irq_save(flags);
- csd->func(csd->info);
- local_irq_restore(flags);
- } else if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
- csd_lock(csd);
- generic_exec_single(cpu, csd, wait);
- } else {
- err = -ENXIO; /* CPU not online */
- }
+ err = generic_exec_single(cpu, csd, csd->func, csd->info, wait);
put_cpu();
+
return err;
}
EXPORT_SYMBOL_GPL(__smp_call_function_single);
--
1.8.3.1


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