md: Protect access to mddev->disks list using RCU
[pandora-kernel.git] / drivers / md / bitmap.c
index eba83e2..621a272 100644 (file)
@@ -241,10 +241,10 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 {
        mdk_rdev_t *rdev;
-       struct list_head *tmp;
        mddev_t *mddev = bitmap->mddev;
 
-       rdev_for_each(rdev, tmp, mddev)
+       rcu_read_lock();
+       rdev_for_each_rcu(rdev, mddev)
                if (test_bit(In_sync, &rdev->flags)
                    && !test_bit(Faulty, &rdev->flags)) {
                        int size = PAGE_SIZE;
@@ -260,11 +260,11 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                                    + (long)(page->index * (PAGE_SIZE/512))
                                    + size/512 > 0)
                                        /* bitmap runs in to metadata */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                                if (rdev->data_offset + mddev->size*2
                                    > rdev->sb_start + bitmap->offset)
                                        /* data runs in to bitmap */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                        } else if (rdev->sb_start < rdev->data_offset) {
                                /* METADATA BITMAP DATA */
                                if (rdev->sb_start
@@ -272,7 +272,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                                    + page->index*(PAGE_SIZE/512) + size/512
                                    > rdev->data_offset)
                                        /* bitmap runs in to data */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                        } else {
                                /* DATA METADATA BITMAP - no problems */
                        }
@@ -282,10 +282,15 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                                       size,
                                       page);
                }
+       rcu_read_unlock();
 
        if (wait)
                md_super_wait(mddev);
        return 0;
+
+ bad_alignment:
+       rcu_read_unlock();
+       return -EINVAL;
 }
 
 static void bitmap_file_kick(struct bitmap *bitmap);