linux-kernel - [PATCH 19/21] ext4: remove repeat assignment to ac_f

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Date:   Fri, 10 Feb 2023 03:48:23 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz
Cc:     linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 19/21] ext4: remove repeat assignment to ac_f_ex

Call trace to assign ac_f_ex:
ext4_mb_use_best_found
	ac->ac_f_ex = ac->ac_b_ex;
	ext4_mb_new_preallocation
		ext4_mb_new_group_pa
			ac->ac_f_ex = ac->ac_b_ex;
		ext4_mb_new_inode_pa
			ac->ac_f_ex = ac->ac_b_ex;

Actually allocated blocks is already stored in ac_f_ex in
ext4_mb_use_best_found, so there is no need to assign ac_f_ex
in ext4_mb_new_group_pa and ext4_mb_new_inode_pa.
Just remove repeat assignment to ac_f_ex in ext4_mb_new_group_pa
and ext4_mb_new_inode_pa.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 fs/ext4/mballoc.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7d6991af50d8..dec716f331ac 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4635,10 +4635,6 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
 	}
 
-	/* preallocation can change ac_b_ex, thus we store actually
-	 * allocated blocks for history */
-	ac->ac_f_ex = ac->ac_b_ex;
-
 	pa->pa_lstart = ac->ac_b_ex.fe_logical;
 	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
 	pa->pa_len = ac->ac_b_ex.fe_len;
@@ -4689,10 +4685,6 @@ ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
 
 	pa = ac->ac_pa;
 
-	/* preallocation can change ac_b_ex, thus we store actually
-	 * allocated blocks for history */
-	ac->ac_f_ex = ac->ac_b_ex;
-
 	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
 	pa->pa_lstart = pa->pa_pstart;
 	pa->pa_len = ac->ac_b_ex.fe_len;
-- 
2.30.0