This splits the code into nicely readable chunks and also avoids
the refcount inc/dec manipulations.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/md/md.c | 84 +++++++++++++++++++++++--------------------------
1 file changed, 39 insertions(+), 45 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index ae076a7a87796..61eceef17d5fd 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3335,14 +3335,33 @@ rdev_size_show(struct md_rdev *rdev, char *page)
return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
}
-static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
+static int md_rdevs_overlap(struct md_rdev *a, struct md_rdev *b)
{
/* check if two start/length pairs overlap */
- if (s1+l1 <= s2)
- return 0;
- if (s2+l2 <= s1)
- return 0;
- return 1;
+ if (a->data_offset + a->sectors <= b->data_offset)
+ return false;
+ if (b->data_offset + b->sectors <= a->data_offset)
+ return false;
+ return true;
+}
+
+static bool md_rdev_overlaps(struct md_rdev *rdev)
+{
+ struct mddev *mddev;
+ struct md_rdev *rdev2;
+
+ spin_lock(&all_mddevs_lock);
+ list_for_each_entry(mddev, &all_mddevs, all_mddevs) {
+ rdev_for_each(rdev2, mddev) {
+ if (rdev != rdev2 && rdev->bdev == rdev2->bdev &&
+ md_rdevs_overlap(rdev, rdev2)) {
+ spin_unlock(&all_mddevs_lock);
+ return true;
+ }
+ }
+ }
+ spin_unlock(&all_mddevs_lock);
+ return false;
}
static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
@@ -3394,46 +3413,21 @@ rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len)
return -EINVAL; /* component must fit device */
rdev->sectors = sectors;
- if (sectors > oldsectors && my_mddev->external) {
- /* Need to check that all other rdevs with the same
- * ->bdev do not overlap. 'rcu' is sufficient to walk
- * the rdev lists safely.
- * This check does not provide a hard guarantee, it
- * just helps avoid dangerous mistakes.
- */
- struct mddev *mddev;
- int overlap = 0;
- struct list_head *tmp;
- rcu_read_lock();
- for_each_mddev(mddev, tmp) {
- struct md_rdev *rdev2;
-
- rdev_for_each(rdev2, mddev)
- if (rdev->bdev == rdev2->bdev &&
- rdev != rdev2 &&
- overlaps(rdev->data_offset, rdev->sectors,
- rdev2->data_offset,
- rdev2->sectors)) {
- overlap = 1;
- break;
- }
- if (overlap) {
- mddev_put(mddev);
- break;
- }
- }
- rcu_read_unlock();
- if (overlap) {
- /* Someone else could have slipped in a size
- * change here, but doing so is just silly.
- * We put oldsectors back because we *know* it is
- * safe, and trust userspace not to race with
- * itself
- */
- rdev->sectors = oldsectors;
- return -EBUSY;
- }
+ /*
+ * Check that all other rdevs with the same bdev do not overlap. This
+ * check does not provide a hard guarantee, it just helps avoid
+ * dangerous mistakes.
+ */
+ if (sectors > oldsectors && my_mddev->external &&
+ md_rdev_overlaps(rdev)) {
+ /*
+ * Someone else could have slipped in a size change here, but
+ * doing so is just silly. We put oldsectors back because we
+ * know it is safe, and trust userspace not to race with itself.
+ */
+ rdev->sectors = oldsectors;
+ return -EBUSY;
}
return len;
}
--
2.30.2
