From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@canonical.com>
Cc: Jens Axboe <axboe@fb.com>,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Al Viro <viro@zeniv.linux.org.uk>,
Maxim Patlasov <mpatlasov@parallels.com>
Subject: Re: [PATCH 1/3] block: loop: use kmap(page) instead of page_address(page)
Date: Tue, 24 Mar 2015 11:29:05 +0100 [thread overview]
Message-ID: <20150324102905.GA7002@lst.de> (raw)
In-Reply-To: <1427012095-4095-2-git-send-email-ming.lei@canonical.com>
On Sun, Mar 22, 2015 at 04:14:52PM +0800, Ming Lei wrote:
> The raw page allocated in lo_send() can be a highmem page,
> so kmap(page) should be used for read/write on the page.
>
> Also the patch removes kmap()/kunmap() in lo_send() because
> it isn't needed at all.
The description seems odd, what it seems to do is to shift the
kmap from lo_send into do_lo_send_write. This does not seem
very useful as it now means a kmap per segment instead of just
a single one per I/O. What would make more sense is to just
not allocate a highmem page.
next prev parent reply other threads:[~2015-03-24 10:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-22 8:14 [PATCH 0/3] block: loop: switch to VFS ITER_BVEC Ming Lei
2015-03-22 8:14 ` [PATCH 1/3] block: loop: use kmap(page) instead of page_address(page) Ming Lei
2015-03-24 10:29 ` Christoph Hellwig [this message]
2015-03-24 10:49 ` Ming Lei
2015-03-24 11:09 ` Christoph Hellwig
2015-03-24 11:24 ` Ming Lei
2015-03-22 8:14 ` [PATCH 2/3] block: loop: unify interface type of lo_send and lo_receive Ming Lei
2015-03-24 10:30 ` Christoph Hellwig
2015-03-24 10:55 ` Ming Lei
2015-03-22 8:14 ` [PATCH 3/3] block: loop: use vfs ITER_BVEC to read/write backing file Ming Lei
2015-03-24 10:31 ` Christoph Hellwig
2015-03-24 11:01 ` Ming Lei
2015-03-24 10:32 ` [PATCH 0/3] block: loop: switch to VFS ITER_BVEC Christoph Hellwig
2015-03-24 10:53 ` Ming Lei
2015-03-24 18:01 ` Christoph Hellwig
2015-03-25 7:23 ` Ming Lei
2015-03-25 15:27 ` Christoph Hellwig
2015-03-31 22:22 ` Al Viro
2015-04-04 5:20 ` Al Viro
2015-04-07 16:23 ` Christoph Hellwig
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