btrfs: read number of data stripes from map only once

There are several places that call nr_data_stripes, but this value does
not change.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 0827bdf4faf14a3718e277f755fe74961e748c95..e51929a55af4c3902116deb9f1af7bb3ec11a4ec 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2660,18 +2660,18 @@ static int get_raid56_logic_offset(u64 physical, int num,
        u64 last_offset;
        u32 stripe_index;
        u32 rot;
+       const int data_stripes = nr_data_stripes(map);
 
-       last_offset = (physical - map->stripes[num].physical) *
-                     nr_data_stripes(map);
+       last_offset = (physical - map->stripes[num].physical) * data_stripes;
        if (stripe_start)
                *stripe_start = last_offset;
 
        *offset = last_offset;
-       for (i = 0; i < nr_data_stripes(map); i++) {
+       for (i = 0; i < data_stripes; i++) {
                *offset = last_offset + i * map->stripe_len;
 
                stripe_nr = div64_u64(*offset, map->stripe_len);
-               stripe_nr = div_u64(stripe_nr, nr_data_stripes(map));
+               stripe_nr = div_u64(stripe_nr, data_stripes);
 
                /* Work out the disk rotation on this stripe-set */
                stripe_nr = div_u64_rem(stripe_nr, map->num_stripes, &rot);

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index eb737bcd7aac6493e2040f2ab1345ce55dfa88bd..5514ae801f4c3954bc78866b53d1b2f01bbb3ac2 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5918,6 +5918,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
        u64 stripe_nr;
        u64 stripe_len;
        u32 stripe_index;
+       int data_stripes;
        int i;
        int ret = 0;
        int num_stripes;
@@ -5949,6 +5950,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
         * to get to this block
         */
        stripe_nr = div64_u64(stripe_nr, stripe_len);
+       data_stripes = nr_data_stripes(map);
 
        stripe_offset = stripe_nr * stripe_len;
        if (offset < stripe_offset) {
@@ -5965,7 +5967,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 
        /* if we're here for raid56, we need to know the stripe aligned start */
        if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
-               unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
+               unsigned long full_stripe_len = stripe_len * data_stripes;
                raid56_full_stripe_start = offset;
 
                /* allow a write of a full stripe, but make sure we don't
@@ -5983,7 +5985,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
                   stripe (on a single disk). */
                if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
                    (op == BTRFS_MAP_WRITE)) {
-                       max_len = stripe_len * nr_data_stripes(map) -
+                       max_len = stripe_len * data_stripes -
                                (offset - raid56_full_stripe_start);
                } else {
                        /* we limit the length of each bio to what fits in a stripe */
@@ -6073,7 +6075,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
                if (need_raid_map && (need_full_stripe(op) || mirror_num > 1)) {
                        /* push stripe_nr back to the start of the full stripe */
                        stripe_nr = div64_u64(raid56_full_stripe_start,
-                                       stripe_len * nr_data_stripes(map));
+                                       stripe_len * data_stripes);
 
                        /* RAID[56] write or recovery. Return all stripes */
                        num_stripes = map->num_stripes;
@@ -6089,10 +6091,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
                         * Mirror #3 is RAID6 Q block.
                         */
                        stripe_nr = div_u64_rem(stripe_nr,
-                                       nr_data_stripes(map), &stripe_index);
+                                       data_stripes, &stripe_index);
                        if (mirror_num > 1)
-                               stripe_index = nr_data_stripes(map) +
-                                               mirror_num - 2;
+                               stripe_index = data_stripes + mirror_num - 2;
 
                        /* We distribute the parity blocks across stripes */
                        div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
@@ -6150,8 +6151,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
                div_u64_rem(stripe_nr, num_stripes, &rot);
 
                /* Fill in the logical address of each stripe */
-               tmp = stripe_nr * nr_data_stripes(map);
-               for (i = 0; i < nr_data_stripes(map); i++)
+               tmp = stripe_nr * data_stripes;
+               for (i = 0; i < data_stripes; i++)
                        bbio->raid_map[(i+rot) % num_stripes] =
                                em->start + (tmp + i) * map->stripe_len;