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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Ilya Dryomov <idryomov@gmail.com>
Cc: Jeff Layton <jlayton@redhat.com>, "Yan, Zheng" <zyan@redhat.com>,
	Sage Weil <sage@redhat.com>,
	Ceph Development <ceph-devel@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Zhu, Caifeng" <zhucaifeng@unissoft-nj.com>
Subject: Re: [PATCH v2] ceph/iov_iter: fix bad iov_iter handling in ceph splice codepaths
Date: Thu, 12 Jan 2017 11:37:43 +0000	[thread overview]
Message-ID: <20170112113743.GX1555@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CAOi1vP_EB5Eq6eGsDzVyYQpwDRYk=3JuTnro_EJRfqTNcYKknQ@mail.gmail.com>

On Thu, Jan 12, 2017 at 12:13:31PM +0100, Ilya Dryomov wrote:

> It would be a significant and wide-reaching change, but I've been
> meaning to look into switching to iov_iter for a couple of releases
> now.  There is a lot of ugly code in net/ceph/messenger.c to hangle
> iteration over "page vectors", "page lists" and "bio lists".  All of it
> predates iov_iter proliferation and is mostly incomplete anyway: IIRC
> you can send out of a pagelist but can't recv into a pagelist, etc.

Wait a sec...  Is it done from the same thread that has issued a syscall?
If so, we certainly could just pass iov_iter without bothering with any
form of ..._get_pages(); if not, we'll need at least to get from iovec
to bio_vec, since userland addresses make sense only in the caller's
context...

  reply	other threads:[~2017-01-12 11:37 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-06 18:23 [PATCH] ceph/iov_iter: fix bad iov_iter handling in ceph splice codepaths Jeff Layton
2017-01-06 20:36 ` Jeff Layton
2017-01-09 23:11 ` Jeff Layton
2017-01-10 12:57 ` [PATCH v2] " Jeff Layton
2017-01-11  2:42   ` Yan, Zheng
2017-01-12  7:59   ` Al Viro
2017-01-12 11:13     ` Ilya Dryomov
2017-01-12 11:37       ` Al Viro [this message]
2017-01-12 11:46         ` Ilya Dryomov
2017-01-12 11:53           ` Al Viro
2017-01-12 12:17             ` Ilya Dryomov
2017-01-12 11:57           ` Jeff Layton
2017-01-12 11:27     ` Jeff Layton
2017-01-12 11:37       ` Ilya Dryomov
2017-01-18 12:14         ` Jeff Layton
2017-01-24 15:00           ` Jeff Layton
2017-01-24 20:51             ` Jeff Layton

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