From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@canonical.com>
Cc: Christoph Hellwig <hch@lst.de>, Al Viro <viro@zeniv.linux.org.uk>,
Jens Axboe <axboe@fb.com>,
Nicholas Bellinger <nab@linux-iscsi.org>,
linux-fsdevel@vger.kernel.org, target-devel@vger.kernel.org
Subject: Re: [PATCH 3/3] target: use vfs_bvec_read/write
Date: Sun, 25 Jan 2015 14:43:04 +0100 [thread overview]
Message-ID: <20150125134304.GA21974@lst.de> (raw)
In-Reply-To: <CACVXFVMK0wBE+0s0-J9sow-ozk0E_T-G1ueiKZ-YtchLzjz1SA@mail.gmail.com>
On Fri, Jan 23, 2015 at 10:08:01PM +0800, Ming Lei wrote:
> >
> > for_each_sg(sgl, sg, sgl_nents, i) {
> > - iov[i].iov_len = sg->length;
> > - iov[i].iov_base = kmap(sg_page(sg)) + sg->offset;
> > - }
> > + bvec[i].bv_page = sg_page(sg);
> > + bvec[i].bv_len = sg->length;
> > + bvec[i].bv_offset = sg->offset;
>
> Sorry, I have one question: I understand one bvec should only cover
> one page, but
> one sg may cover lots of pages, so could ITER_BVEC handle that correctly?
Each scatterlist entry only contains a single page, which is returned
by sg_page(sg). The existing code already relies on it because it
kmaps that page.
next prev parent reply other threads:[~2015-01-25 13:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-18 15:07 switch loop and target to use ITER_BVEC iov_iter Christoph Hellwig
2015-01-18 15:07 ` [PATCH 1/3] fs: add vfs_bvec_{read,write} helpers Christoph Hellwig
2015-01-23 6:00 ` Al Viro
2015-01-18 15:07 ` [PATCH 2/3] loop: convert to vfs_bvec_write Christoph Hellwig
2015-01-18 15:07 ` [PATCH 3/3] target: use vfs_bvec_read/write Christoph Hellwig
2015-01-18 15:37 ` Sagi Grimberg
2015-01-20 23:32 ` Nicholas A. Bellinger
2015-01-23 14:08 ` Ming Lei
2015-01-25 13:43 ` Christoph Hellwig [this message]
2015-01-26 2:02 ` Ming Lei
2015-01-26 16:59 ` Christoph Hellwig
2015-01-27 5:14 ` Ming Lei
2015-01-22 4:11 ` switch loop and target to use ITER_BVEC iov_iter Ming Lei
2015-01-25 13:45 ` Christoph Hellwig
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