From: Christoph Hellwig <hch@infradead.org>
To: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: David Sterba <dsterba@suse.cz>,
"linux-btrfs @ vger . kernel . org" <linux-btrfs@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v7 2/8] btrfs: don't kmap() pages from block devices
Date: Tue, 11 Feb 2020 23:25:24 -0800 [thread overview]
Message-ID: <20200212072524.GA30977@infradead.org> (raw)
In-Reply-To: <20200212071704.17505-3-johannes.thumshirn@wdc.com>
On Wed, Feb 12, 2020 at 04:16:58PM +0900, Johannes Thumshirn wrote:
> Block device mappings are never in highmem so kmap() / kunmap() calls for
> pages from block devices are unneeded. Use page_address() instead of
> kmap() to get to the virtual addreses.
>
> While we're at it, read_cache_page_gfp() doesn't return NULL on error,
> only an ERR_PTR, so use IS_ERR() to check for errors.
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2020-02-12 7:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 7:16 [PATCH v7 0/8] btrfs: remove buffer heads form superblock handling Johannes Thumshirn
2020-02-12 7:16 ` [PATCH v7 1/8] btrfs: Export btrfs_release_disk_super Johannes Thumshirn
2020-02-12 7:16 ` [PATCH v7 2/8] btrfs: don't kmap() pages from block devices Johannes Thumshirn
2020-02-12 7:25 ` Christoph Hellwig [this message]
2020-02-12 7:16 ` [PATCH v7 3/8] btrfs: unexport btrfs_scratch_superblocks Johannes Thumshirn
2020-02-12 7:27 ` Christoph Hellwig
2020-02-12 7:51 ` Johannes Thumshirn
2020-02-12 7:17 ` [PATCH v7 4/8] btrfs: use the page-cache for super block reading Johannes Thumshirn
2020-02-12 7:28 ` Christoph Hellwig
2020-02-12 7:43 ` Johannes Thumshirn
2020-02-12 7:17 ` [PATCH v7 5/8] btrfs: use BIOs instead of buffer_heads from superblock writeout Johannes Thumshirn
2020-02-12 7:30 ` Christoph Hellwig
2020-02-12 7:17 ` [PATCH v7 6/8] btrfs: remove btrfsic_submit_bh() Johannes Thumshirn
2020-02-12 7:17 ` [PATCH v7 7/8] btrfs: remove buffer_heads from btrfsic_process_written_block() Johannes Thumshirn
2020-02-12 7:17 ` [PATCH v7 8/8] btrfs: remove buffer_heads form superblock mirror integrity checking Johannes Thumshirn
2020-02-12 17:06 ` David Sterba
2020-02-13 9:12 ` Johannes Thumshirn
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