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From: Chunguang Xu <brookxu.cn@gmail.com>
To: tytso@mit.edu, adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org
Subject: [PATCH RESEND 3/8] ext4: simplify the code of mb_find_order_for_block
Date: Sat,  7 Nov 2020 23:58:13 +0800	[thread overview]
Message-ID: <1604764698-4269-3-git-send-email-brookxu@tencent.com> (raw)
In-Reply-To: <1604764698-4269-1-git-send-email-brookxu@tencent.com>

From: Chunguang Xu <brookxu@tencent.com>

The code of mb_find_order_for_block is a bit obscure, but we can
simplify it with mb_find_buddy(), make the code more concise.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
 fs/ext4/mballoc.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 5b74555..29dfeb04 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1289,22 +1289,18 @@ static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
 
 static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
 {
-	int order = 1;
-	int bb_incr = 1 << (e4b->bd_blkbits - 1);
+	int order = 1, max;
 	void *bb;
 
 	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
 	BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
 
-	bb = e4b->bd_buddy;
 	while (order <= e4b->bd_blkbits + 1) {
-		block = block >> 1;
-		if (!mb_test_bit(block, bb)) {
+		bb = mb_find_buddy(e4b, order, &max);
+		if (!mb_test_bit(block >> order, bb)) {
 			/* this block is part of buddy of order 'order' */
 			return order;
 		}
-		bb += bb_incr;
-		bb_incr >>= 1;
 		order++;
 	}
 	return 0;
-- 
1.8.3.1


  parent reply	other threads:[~2020-11-07 15:58 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-07 15:58 [PATCH RESEND 1/8] ext4: use ext4_assert() to replace J_ASSERT() Chunguang Xu
2020-11-07 15:58 ` [PATCH RESEND 2/8] ext4: remove redundant mb_regenerate_buddy() Chunguang Xu
2020-12-03 14:42   ` Theodore Y. Ts'o
2020-11-07 15:58 ` Chunguang Xu [this message]
2020-12-03 14:43   ` [PATCH RESEND 3/8] ext4: simplify the code of mb_find_order_for_block Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH RESEND 4/8] ext4: add the gdt block of meta_bg to system_zone Chunguang Xu
2020-12-03 15:08   ` Theodore Y. Ts'o
2020-12-04  1:26     ` brookxu
2020-12-09  4:34       ` Theodore Y. Ts'o
2020-12-09 11:48         ` brookxu
2020-12-09 19:39           ` Theodore Y. Ts'o
2020-12-10 11:00             ` brookxu
2020-12-15  1:14             ` brookxu
2020-12-15 20:13               ` Theodore Y. Ts'o
2020-12-17 16:01                 ` Andreas Dilger
2020-12-04  1:29     ` brookxu
2020-11-07 15:58 ` [PATCH RESEND 5/8] ext4: update ext4_data_block_valid related comments Chunguang Xu
2020-12-09 19:11   ` Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH 6/8] ext4: add a helper function to validate metadata block Chunguang Xu
2020-12-09  4:55   ` Theodore Y. Ts'o
2020-12-09 12:12     ` brookxu
2020-11-07 15:58 ` [PATCH RESEND 7/8] ext4: delete invalid code inside ext4_xattr_block_set() Chunguang Xu
2020-12-09 19:24   ` Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH RESEND 8/8] ext4: fix a memory leak of ext4_free_data Chunguang Xu
2020-12-09 19:29   ` Theodore Y. Ts'o
2020-12-03 14:38 ` [PATCH RESEND 1/8] ext4: use ext4_assert() to replace J_ASSERT() Theodore Y. Ts'o

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