smp: Teach __smp_call_function_single() to check for offline cpus

Align __smp_call_function_single() with smp_call_function_single() so
that it also checks whether requested cpu is still online.

Signed-off-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: Jens Axboe <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 4991c6b..c39074c 100644 (file)
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -50,8 +50,7 @@ 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);
 
-void __smp_call_function_single(int cpuid, struct call_single_data *data,
-                               int wait);
+int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait);
 
 #ifdef CONFIG_SMP
 

diff --git a/kernel/smp.c b/kernel/smp.c
index e3852de..5ff14e3 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -276,18 +276,18 @@ EXPORT_SYMBOL_GPL(smp_call_function_any);
 /**
  * __smp_call_function_single(): Run a function on a specific CPU
  * @cpu: The CPU to run on.
- * @data: Pre-allocated and setup data structure
+ * @csd: Pre-allocated and setup data structure
  * @wait: If true, wait until function has completed on specified CPU.
  *
  * Like smp_call_function_single(), but allow caller to pass in a
  * pre-allocated data structure. Useful for embedding @data inside
  * other structures, for instance.
  */
-void __smp_call_function_single(int cpu, struct call_single_data *csd,
-                               int wait)
+int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait)
 {
        unsigned int this_cpu;
        unsigned long flags;
+       int err = 0;
 
        this_cpu = get_cpu();
        /*
@@ -303,11 +303,14 @@ void __smp_call_function_single(int cpu, struct call_single_data *csd,
                local_irq_save(flags);
                csd->func(csd->info);
                local_irq_restore(flags);
-       } else {
+       } 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 */
        }
        put_cpu();
+       return err;
 }
 EXPORT_SYMBOL_GPL(__smp_call_function_single);
 

diff --git a/kernel/up.c b/kernel/up.c
index 509403e..cdf03d1 100644 (file)
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -22,14 +22,15 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
 }
 EXPORT_SYMBOL(smp_call_function_single);
 
-void __smp_call_function_single(int cpu, struct call_single_data *csd,
-                               int wait)
+int __smp_call_function_single(int cpu, struct call_single_data *csd,
+                              int wait)
 {
        unsigned long flags;
 
        local_irq_save(flags);
        csd->func(csd->info);
        local_irq_restore(flags);
+       return 0;
 }
 EXPORT_SYMBOL(__smp_call_function_single);