ext4: introduce ext4_get_group_number()

Currently on many places in ext4 we're using
ext4_get_group_no_and_offset() even though we're only interested in
knowing the block group of the particular block, not the offset within
the block group so we can use more efficient way to compute block
group.

This patch introduces ext4_get_group_number() which computes block
group for a given block much more efficiently. Use this function
instead of ext4_get_group_no_and_offset() everywhere where we're only
interested in knowing the block group.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 580aada3d1bb..8c8d05218021 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3344,7 +3344,7 @@ static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
         if (pa->pa_type == MB_GROUP_PA)
                 grp_blk--;
 
-        ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
+        grp = ext4_get_group_number(sb, grp_blk);
 
         /*
          * possible race:
@@ -3809,7 +3809,7 @@ repeat:
 
         list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
                 BUG_ON(pa->pa_type != MB_INODE_PA);
-                ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
+                group = ext4_get_group_number(sb, pa->pa_pstart);
 
                 err = ext4_mb_load_buddy(sb, group, &e4b);
                 if (err) {
@@ -4071,7 +4071,7 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb,
 
         list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
 
-                ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
+                group = ext4_get_group_number(sb, pa->pa_pstart);
                 if (ext4_mb_load_buddy(sb, group, &e4b)) {
                         ext4_error(sb, "Error loading buddy information for %u",
                                         group);