gru: handle failures to mmu_notifier_register

Under some conditions, mmu_notifier_register() will fail to register a
mmu_notifier.  Fix the GRU driver to correctly handle these failures.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/misc/sgi-gru/grutlbpurge.c b/drivers/misc/sgi-gru/grutlbpurge.c
index 1d125091f5e7..421c548e51f1 100644
--- a/drivers/misc/sgi-gru/grutlbpurge.c
+++ b/drivers/misc/sgi-gru/grutlbpurge.c
@@ -299,6 +299,7 @@ struct gru_mm_struct *gru_register_mmu_notifier(void)
 {
         struct gru_mm_struct *gms;
         struct mmu_notifier *mn;
+        int err;
 
         mn = mmu_find_ops(current->mm, &gru_mmuops);
         if (mn) {
@@ -311,12 +312,17 @@ struct gru_mm_struct *gru_register_mmu_notifier(void)
                         gms->ms_notifier.ops = &gru_mmuops;
                         atomic_set(&gms->ms_refcnt, 1);
                         init_waitqueue_head(&gms->ms_wait_queue);
-                        __mmu_notifier_register(&gms->ms_notifier, current->mm);
+                        err = __mmu_notifier_register(&gms->ms_notifier, current->mm);
+                        if (err)
+                                goto error;
                 }
         }
         gru_dbg(grudev, "gms %p, refcnt %d\n", gms,
                 atomic_read(&gms->ms_refcnt));
         return gms;
+error:
+        kfree(gms);
+        return ERR_PTR(err);
 }
 
 void gru_drop_mmu_notifier(struct gru_mm_struct *gms)