linux-ext4 - Re: [PATCH 10/25] ext4: add EXT4_LBLK_TO_P and EXT4_P_TO

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Message-ID: <pgrk2x54egzxcvmfi4rra3exooxe3yxuvug6yvbtrgxm2oppym@fy52xh4weeww>
Date: Mon, 3 Nov 2025 09:26:47 +0100
From: Jan Kara <jack@...e.cz>
To: libaokun@...weicloud.com
Cc: linux-ext4@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca, 
	jack@...e.cz, linux-kernel@...r.kernel.org, kernel@...kajraghav.com, 
	mcgrof@...nel.org, linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, 
	yi.zhang@...wei.com, yangerkun@...wei.com, chengzhihao1@...wei.com, 
	libaokun1@...wei.com
Subject: Re: [PATCH 10/25] ext4: add EXT4_LBLK_TO_P and EXT4_P_TO_LBLK for
 block/page conversion

On Sat 25-10-25 11:22:06, libaokun@...weicloud.com wrote:
> From: Baokun Li <libaokun1@...wei.com>
> 
> As BS > PS support is coming, all block number to page index (and
> vice-versa) conversions must now go via bytes. Added EXT4_LBLK_TO_P()
> and EXT4_P_TO_LBLK() macros to simplify these conversions and handle
> both BS <= PS and BS > PS scenarios cleanly.
> 
> Signed-off-by: Baokun Li <libaokun1@...wei.com>
> Reviewed-by: Zhang Yi <yi.zhang@...wei.com>

'P' in the macro names seems too terse :). I'd probably use PG to give a
better hint this is about pages? So EXT4_LBLK_TO_PG() and
EXT4_PG_TO_LBLK(). BTW, patch 8 could already use these macros...

								Honza

> ---
>  fs/ext4/ext4.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 9b236f620b3a..8223ed29b343 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -369,6 +369,12 @@ struct ext4_io_submit {
>  	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
>  #define EXT4_LBLK_TO_B(inode, lblk) ((loff_t)(lblk) << (inode)->i_blkbits)
>  
> +/* Translate a block number to a page index */
> +#define EXT4_LBLK_TO_P(inode, lblk)	(EXT4_LBLK_TO_B((inode), (lblk)) >> \
> +					 PAGE_SHIFT)
> +/* Translate a page index to a block number */
> +#define EXT4_P_TO_LBLK(inode, pnum)	(((loff_t)(pnum) << PAGE_SHIFT) >> \
> +					 (inode)->i_blkbits)
>  /* Translate a block number to a cluster number */
>  #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
>  /* Translate a cluster number to a block number */
> -- 
> 2.46.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR