From: Ilya Dryomov <idryomov@gmail.com>
To: Al Viro <viro@zeniv.linux.org.uk>
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 12:46:42 +0100 [thread overview]
Message-ID: <CAOi1vP8Gu+Gc0+y8J5G9H14qGh=8o9SuHwYHKFQJgWy3vJQr8Q@mail.gmail.com> (raw)
In-Reply-To: <20170112113743.GX1555@ZenIV.linux.org.uk>
On Thu, Jan 12, 2017 at 12:37 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> 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...
No, not necessarily - it's also used by rbd (all of net/ceph has two
users: fs/ceph and drivers/block/rbd.c).
Thanks,
Ilya
next prev parent reply other threads:[~2017-01-12 11:46 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
2017-01-12 11:46 ` Ilya Dryomov [this message]
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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