ext4: remove page offset calculation in ext4_block_zero_page_range()

For bs <= ps scenarios, calculating the offset within the block is
sufficient. For bs > ps, an initial page offset calculation can lead to
incorrect behavior. Thus this redundant calculation has been removed.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251121090654.631996-2-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: Zhihao Cheng

fs/ext4/inode.c

@@ -4167,9 +4167,8 @@ static int ext4_block_zero_page_range(handle_t *handle,
 		struct address_space *mapping, loff_t from, loff_t length)
 {
 	struct inode *inode = mapping->host;
-	unsigned offset = from & (PAGE_SIZE-1);
 	unsigned blocksize = inode->i_sb->s_blocksize;
-	unsigned max = blocksize - (offset & (blocksize - 1));
+	unsigned int max = blocksize - (from & (blocksize - 1));
 
 	/*
 	 * correct length if it does not fall between