From: Eric Biggers <ebiggers@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Chao Yu <chao@kernel.org>, Christian Brauner <brauner@kernel.org>,
"Darrick J. Wong" <djwong@kernel.org>,
linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 14/14] ext4: use a byte granularity cursor in ext4_mpage_readpages
Date: Fri, 27 Feb 2026 14:29:50 -0800 [thread overview]
Message-ID: <20260227222950.GC5357@quark> (raw)
In-Reply-To: <20260226144954.142278-15-hch@lst.de>
On Thu, Feb 26, 2026 at 06:49:34AM -0800, Christoph Hellwig wrote:
> + block_in_file = EXT4_PG_TO_LBLK(inode, folio->index);
> + pos = (loff_t)block_in_file << blkbits;
The EXT4_PG_TO_LBLK() expands to:
(((loff_t)(folio->index) << PAGE_SHIFT) >> (inode)->i_blkbits)
So it calculates the pos as an intermediate step, and we end up with the
redundant pos = (pos >> blkbits) << blkbits.
It probably would make more sense to calculate the pos first, similar to
what other places in this series do:
pos = folio_pos(folio);
block_in_file = pos >> blkbits;
- Eric
WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
To: Christoph Hellwig <hch@lst.de>
Cc: Christian Brauner <brauner@kernel.org>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
"Darrick J. Wong" <djwong@kernel.org>,
linux-f2fs-devel@lists.sourceforge.net,
linux-fscrypt@vger.kernel.org,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-fsdevel@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
linux-ext4@vger.kernel.org
Subject: Re: [f2fs-dev] [PATCH 14/14] ext4: use a byte granularity cursor in ext4_mpage_readpages
Date: Fri, 27 Feb 2026 14:29:50 -0800 [thread overview]
Message-ID: <20260227222950.GC5357@quark> (raw)
In-Reply-To: <20260226144954.142278-15-hch@lst.de>
On Thu, Feb 26, 2026 at 06:49:34AM -0800, Christoph Hellwig wrote:
> + block_in_file = EXT4_PG_TO_LBLK(inode, folio->index);
> + pos = (loff_t)block_in_file << blkbits;
The EXT4_PG_TO_LBLK() expands to:
(((loff_t)(folio->index) << PAGE_SHIFT) >> (inode)->i_blkbits)
So it calculates the pos as an intermediate step, and we end up with the
redundant pos = (pos >> blkbits) << blkbits.
It probably would make more sense to calculate the pos first, similar to
what other places in this series do:
pos = folio_pos(folio);
block_in_file = pos >> blkbits;
- Eric
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https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2026-02-27 22:29 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-26 14:49 fscrypt API cleanups v2 Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 01/14] ext4: initialize the write hint in io_submit_init_bio Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-27 21:16 ` Eric Biggers
2026-02-27 21:16 ` [f2fs-dev] " Eric Biggers via Linux-f2fs-devel
2026-02-26 14:49 ` [PATCH 02/14] ext4: open code fscrypt_set_bio_crypt_ctx_bh Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-27 21:19 ` Eric Biggers
2026-02-27 21:19 ` [f2fs-dev] " Eric Biggers via Linux-f2fs-devel
2026-02-26 14:49 ` [PATCH 03/14] ext4: factor out a io_submit_need_new_bio helper Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 04/14] ext4, fscrypt: merge fscrypt_mergeable_bio_bh into io_submit_need_new_bio Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-27 21:22 ` Eric Biggers
2026-02-27 21:22 ` [f2fs-dev] " Eric Biggers via Linux-f2fs-devel
2026-02-26 14:49 ` [PATCH 05/14] fscrypt: move fscrypt_set_bio_crypt_ctx_bh to buffer.c Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-27 21:54 ` Eric Biggers
2026-02-27 21:54 ` [f2fs-dev] " Eric Biggers via Linux-f2fs-devel
2026-02-26 14:49 ` [PATCH 06/14] fscrypt: pass a byte offset to fscrypt_generate_dun Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 07/14] fscrypt: pass a byte offset to fscrypt_mergeable_bio Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 08/14] fscrypt: pass a byte offset to fscrypt_set_bio_crypt_ctx Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 09/14] fscrypt: pass a byte offset to fscrypt_zeroout_range_inline_crypt Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 10/14] fscrypt: pass a byte length " Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 11/14] fscrypt: pass a byte offset to fscrypt_zeroout_range Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 12/14] fscrypt: pass a byte length " Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-27 22:14 ` Eric Biggers
2026-02-27 22:14 ` [f2fs-dev] " Eric Biggers via Linux-f2fs-devel
2026-02-26 14:49 ` [PATCH 13/14] fscrypt: pass a real sector_t " Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-26 14:49 ` [PATCH 14/14] ext4: use a byte granularity cursor in ext4_mpage_readpages Christoph Hellwig
2026-02-26 14:49 ` [f2fs-dev] " Christoph Hellwig
2026-02-27 22:29 ` Eric Biggers [this message]
2026-02-27 22:29 ` Eric Biggers via Linux-f2fs-devel
-- strict thread matches above, loose matches on Subject: below --
2026-03-02 14:18 fscrypt API cleanups v3 Christoph Hellwig
2026-03-02 14:18 ` [PATCH 14/14] ext4: use a byte granularity cursor in ext4_mpage_readpages Christoph Hellwig
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