drbd: use the cached meta_dev_idx

Now we have the cached meta_dev_idx member,
we can get rid of a few rcu_read_lock() sections and rcu_dereference().

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 5 insertions, 27 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index ee19ba28b59a..6eecdec9da2b 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1777,9 +1777,9 @@ static inline void drbd_chk_io_error_(struct drbd_conf *mdev,
  * BTW, for internal meta data, this happens to be the maximum capacity
  * we could agree upon with our peer node.
  */
-static inline sector_t _drbd_md_first_sector(int meta_dev_idx, struct drbd_backing_dev *bdev)
+static inline sector_t drbd_md_first_sector(struct drbd_backing_dev *bdev)
 {
-        switch (meta_dev_idx) {
+        switch (bdev->md.meta_dev_idx) {
         case DRBD_MD_INDEX_INTERNAL:
         case DRBD_MD_INDEX_FLEX_INT:
                 return bdev->md.md_offset + bdev->md.bm_offset;
@@ -1789,30 +1789,13 @@ static inline sector_t _drbd_md_first_sector(int meta_dev_idx, struct drbd_backi
         }
 }
 
-static inline sector_t drbd_md_first_sector(struct drbd_backing_dev *bdev)
-{
-        int meta_dev_idx;
-
-        rcu_read_lock();
-        meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;
-        rcu_read_unlock();
-
-        return _drbd_md_first_sector(meta_dev_idx, bdev);
-}
-
 /**
  * drbd_md_last_sector() - Return the last sector number of the meta data area
  * @bdev:       Meta data block device.
  */
 static inline sector_t drbd_md_last_sector(struct drbd_backing_dev *bdev)
 {
-        int meta_dev_idx;
-
-        rcu_read_lock();
-        meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;
-        rcu_read_unlock();
-
-        switch (meta_dev_idx) {
+        switch (bdev->md.meta_dev_idx) {
         case DRBD_MD_INDEX_INTERNAL:
         case DRBD_MD_INDEX_FLEX_INT:
                 return bdev->md.md_offset + MD_4kB_SECT -1;
@@ -1840,18 +1823,13 @@ static inline sector_t drbd_get_capacity(struct block_device *bdev)
 static inline sector_t drbd_get_max_capacity(struct drbd_backing_dev *bdev)
 {
         sector_t s;
-        int meta_dev_idx;
-
-        rcu_read_lock();
-        meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;
-        rcu_read_unlock();
 
-        switch (meta_dev_idx) {
+        switch (bdev->md.meta_dev_idx) {
         case DRBD_MD_INDEX_INTERNAL:
         case DRBD_MD_INDEX_FLEX_INT:
                 s = drbd_get_capacity(bdev->backing_bdev)
                         ? min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
-                                _drbd_md_first_sector(meta_dev_idx, bdev))
+                                drbd_md_first_sector(bdev))
                         : 0;
                 break;
         case DRBD_MD_INDEX_FLEX_EXT: