linux-ext4 - [PATCH] ext4: simplify 32bit calculation of lblk

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Message-Id: <20230403135304.19858-1-wuchi.zero@gmail.com>
Date:   Mon,  3 Apr 2023 21:53:04 +0800
From:   wuchi <wuchi.zero@...il.com>
To:     tytso@....edu, adilger.kernel@...ger.ca, ojaswin@...ux.ibm.com,
        ritesh.list@...il.com
Cc:     linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] ext4: simplify 32bit calculation of lblk

commit <ad4fb9cafe100a> (ext4: fix 32bit overflow in ext4_ext_find_goal())
uses value compare to fix 32bit overflow. Try to simplify that.

Signed-off-by: wuchi <wuchi.zero@...il.com>
---
 fs/ext4/extents.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 3559ea6b0781..324b7d1386e0 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -237,10 +237,7 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 
-			if (block > ext_block)
-				return ext_pblk + (block - ext_block);
-			else
-				return ext_pblk - (ext_block - block);
+			return ext_pblk + ((signed long long)block - (signed long long)ext_block);
 		}
 
 		/* it looks like index is empty;
-- 
2.20.1