[PATCH] SRCU: report out-of-memory errors

Currently the init_srcu_struct() routine has no way to report out-of-memory
errors.  This patch (as761) makes it return -ENOMEM when the per-cpu data
allocation fails.

The patch also makes srcu_init_notifier_head() report a BUG if a notifier
head can't be initialized.  Perhaps it should return -ENOMEM instead, but
in the most likely cases where this might occur I don't think any recovery
is possible.  Notifier chains generally are not created dynamically.

[akpm@osdl.org: avoid statement-with-side-effect in macro]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/kernel/srcu.c b/kernel/srcu.c
index 7e1979f624ba..3507cabe963b 100644
--- a/kernel/srcu.c
+++ b/kernel/srcu.c
@@ -42,11 +42,12 @@
  * to any other function.  Each srcu_struct represents a separate domain
  * of SRCU protection.
  */
-void init_srcu_struct(struct srcu_struct *sp)
+int init_srcu_struct(struct srcu_struct *sp)
 {
         sp->completed = 0;
-        sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
         mutex_init(&sp->mutex);
+        sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
+        return (sp->per_cpu_ref ? 0 : -ENOMEM);
 }
 
 /*