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>

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index ee19ba28b59afe61d40ca183cbfa84880033ad56..6eecdec9da2b0de93d5f1243bb1504ca3c440e91 100644 (file)
--- 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:

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 104b7cea691e64cd8bd9ea722e72a277f4cea27c..5621df86967aea4e0b91346058d06c999e916603 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -722,14 +722,10 @@ static void drbd_md_set_sector_offsets(struct drbd_conf *mdev,
 {
        sector_t md_size_sect = 0;
        unsigned int al_size_sect = MD_32kB_SECT;
-       int meta_dev_idx;
-
-       rcu_read_lock();
-       meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;
 
        bdev->md.md_offset = drbd_md_ss(bdev);
 
-       switch (meta_dev_idx) {
+       switch (bdev->md.meta_dev_idx) {
        default:
                /* v07 style fixed size indexed meta data */
                bdev->md.md_size_sect = MD_128MB_SECT;
@@ -761,7 +757,6 @@ static void drbd_md_set_sector_offsets(struct drbd_conf *mdev,
                bdev->md.bm_offset   = -md_size_sect + MD_4kB_SECT;
                break;
        }
-       rcu_read_unlock();
 }
 
 /* input size is expected to be in KB */