[PATCH v2 11/16] ext4: factor out __ext4_mb_scan_group()

Baokun Li
2025-06-23T07:47:05Z

Extract __ext4_mb_scan_group() to make the code clearer and to
prepare for the later conversion of 'choose group' to 'scan groups'.
No functional changes.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
fs/ext4/mballoc.c | 45 +++++++++++++++++++++++++++------------------
fs/ext4/mballoc.h | 2 ++
2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index dc82124f0905..db5d8b1e5cce 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2569,6 +2569,30 @@ void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
}
}

+static void __ext4_mb_scan_group(struct ext4_allocation_context *ac)
+{
+ bool is_stripe_aligned;
+ struct ext4_sb_info *sbi;
+ enum criteria cr = ac->ac_criteria;
+
+ ac->ac_groups_scanned++;
+ if (cr == CR_POWER2_ALIGNED)
+ return ext4_mb_simple_scan_group(ac, ac->ac_e4b);
+
+ sbi = EXT4_SB(ac->ac_sb);
+ is_stripe_aligned = false;
+ if ((sbi->s_stripe >= sbi->s_cluster_ratio) &&
+ !(ac->ac_g_ex.fe_len % EXT4_NUM_B2C(sbi, sbi->s_stripe)))
+ is_stripe_aligned = true;
+
+ if ((cr == CR_GOAL_LEN_FAST || cr == CR_BEST_AVAIL_LEN) &&
+ is_stripe_aligned)
+ ext4_mb_scan_aligned(ac, ac->ac_e4b);
+
+ if (ac->ac_status == AC_STATUS_CONTINUE)
+ ext4_mb_complex_scan_group(ac, ac->ac_e4b);
+}
+
/*
* This is also called BEFORE we load the buddy bitmap.
* Returns either 1 or 0 indicating that the group is either suitable
@@ -2855,6 +2879,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
*/
if (ac->ac_2order)
cr = CR_POWER2_ALIGNED;
+
+ ac->ac_e4b = &e4b;
repeat:
for (; cr < EXT4_MB_NUM_CRS && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
ac->ac_criteria = cr;
@@ -2932,24 +2958,7 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
continue;
}

- ac->ac_groups_scanned++;
- if (cr == CR_POWER2_ALIGNED)
- ext4_mb_simple_scan_group(ac, &e4b);
- else {
- bool is_stripe_aligned =
- (sbi->s_stripe >=
- sbi->s_cluster_ratio) &&
- !(ac->ac_g_ex.fe_len %
- EXT4_NUM_B2C(sbi, sbi->s_stripe));
-
- if ((cr == CR_GOAL_LEN_FAST ||
- cr == CR_BEST_AVAIL_LEN) &&
- is_stripe_aligned)
- ext4_mb_scan_aligned(ac, &e4b);
-
- if (ac->ac_status == AC_STATUS_CONTINUE)
- ext4_mb_complex_scan_group(ac, &e4b);
- }
+ __ext4_mb_scan_group(ac);

ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 38c37901728d..d61d690d237c 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -213,6 +213,8 @@ struct ext4_allocation_context {
__u8 ac_2order; /* if request is to allocate 2^N blocks and
* N > 0, the field stores N, otherwise 0 */
__u8 ac_op; /* operation, for history only */
+
+ struct ext4_buddy *ac_e4b;
struct folio *ac_bitmap_folio;
struct folio *ac_buddy_folio;
struct ext4_prealloc_space *ac_pa;
--
2.46.1