[PATCH] md: define and use safe_put_page for md

md sometimes call put_page on NULL pointers (treating it like kfree).  This is
not safe, so define and use a 'safe_put_page' which checks for NULL.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 9647ebb0983a..fb952000fae2 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -132,10 +132,10 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 
 out_free_pages:
         for ( ; i > 0 ; i--)
-                put_page(bio->bi_io_vec[i-1].bv_page);
+                safe_put_page(bio->bi_io_vec[i-1].bv_page);
         while (j--)
                 for (i = 0; i < RESYNC_PAGES ; i++)
-                        put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
+                        safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
         j = -1;
 out_free_bio:
         while ( ++j < nalloc )
@@ -155,7 +155,7 @@ static void r10buf_pool_free(void *__r10_bio, void *data)
                 struct bio *bio = r10bio->devs[j].bio;
                 if (bio) {
                         for (i = 0; i < RESYNC_PAGES; i++) {
-                                put_page(bio->bi_io_vec[i].bv_page);
+                                safe_put_page(bio->bi_io_vec[i].bv_page);
                                 bio->bi_io_vec[i].bv_page = NULL;
                         }
                         bio_put(bio);
@@ -2042,7 +2042,7 @@ static int run(mddev_t *mddev)
 out_free_conf:
         if (conf->r10bio_pool)
                 mempool_destroy(conf->r10bio_pool);
-        put_page(conf->tmppage);
+        safe_put_page(conf->tmppage);
         kfree(conf->mirrors);
         kfree(conf);
         mddev->private = NULL;