smp: Consolidate the various smp_call_function_single() declensions

__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().

Reviewed-by: Jan Kara <jack@suse.cz>
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 <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/kernel/smp.c b/kernel/smp.c
index 5ff14e3739ca4e3f49f9d20a75730bf92b54652b..64bb0d48e96f05a3a2a0906149c44a02c98fd469 100644 (file)
--- 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);