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>

1 files changed, 7 insertions, 4 deletions

diff --git a/kernel/smp.c b/kernel/smp.c
index e3852de042a6..5ff14e3739ca 100644
--- 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);