linux-kernel - [PATCH v3 03/10] ext4: return found group directly in ext4_mb_choose_next_group_p2

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Message-Id: <20230801143204.2284343-4-shikemeng@huaweicloud.com>
Date:   Tue,  1 Aug 2023 22:31:57 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     tytso@....edu, adilger.kernel@...ger.ca, ritesh.list@...il.com,
        ojaswin@...ux.ibm.com, linux-ext4@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     shikemeng@...weicloud.com
Subject: [PATCH v3 03/10] ext4: return found group directly in ext4_mb_choose_next_group_p2_aligned

Return good group when it's found in loop to remove unnecessary NULL
initialization of grp and futher check if good group is found after loop.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>
---
 fs/ext4/mballoc.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a6635cba291a..4cbbe930e010 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -874,7 +874,7 @@ static void ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context
 			enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
-	struct ext4_group_info *iter, *grp;
+	struct ext4_group_info *iter;
 	int i;
 
 	if (ac->ac_status == AC_STATUS_FOUND)
@@ -883,7 +883,6 @@ static void ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context
 	if (unlikely(sbi->s_mb_stats && ac->ac_flags & EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED))
 		atomic_inc(&sbi->s_bal_p2_aligned_bad_suggestions);
 
-	grp = NULL;
 	for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) {
 		if (list_empty(&sbi->s_mb_largest_free_orders[i]))
 			continue;
@@ -892,28 +891,22 @@ static void ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context
 			read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
 			continue;
 		}
-		grp = NULL;
 		list_for_each_entry(iter, &sbi->s_mb_largest_free_orders[i],
 				    bb_largest_free_order_node) {
 			if (sbi->s_mb_stats)
 				atomic64_inc(&sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]);
 			if (likely(ext4_mb_good_group(ac, iter->bb_group, CR_POWER2_ALIGNED))) {
-				grp = iter;
-				break;
+				*group = iter->bb_group;
+				ac->ac_flags |= EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED;
+				read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
+				return;
 			}
 		}
 		read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
-		if (grp)
-			break;
 	}
 
-	if (!grp) {
-		/* Increment cr and search again */
-		*new_cr = CR_GOAL_LEN_FAST;
-	} else {
-		*group = grp->bb_group;
-		ac->ac_flags |= EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED;
-	}
+	/* Increment cr and search again if no group is found */
+	*new_cr = CR_GOAL_LEN_FAST;
 }
 
 /*
-- 
2.30.0