netdev - Re: [PATCH v2 08/17] {macvtap,tun}_get_user(): switch to iov

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150203142728.GC29656@ZenIV.linux.org.uk>
Date:	Tue, 3 Feb 2015 14:27:28 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	"Michael S. Tsirkin" <mst@...hat.com>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 08/17] {macvtap,tun}_get_user(): switch to iov_iter

On Tue, Feb 03, 2015 at 12:10:44PM +0200, Michael S. Tsirkin wrote:

> Hmm does copy_from_iter actually modify the iovec?
> If so, won't this break aio on tun/macvtap, by
> reversing the effect of
> commit 6f26c9a7555e5bcca3560919db9b852015077dae
>     tun: fix tun_chr_aio_write so that aio works
> ?
> 
> 
> Maybe we should change iovec_iter to avoid modifying the
> underlying iovec?

iov_iter never changes the underlying iovec (or kvec, or bvec).
iter->iov_offset changes as you go and once you have consumed an
entire iovec element ->iov is incremented to point to the next one
(and ->iov_offset is reset to 0 at that point).  *Contents* of
iter->iov is never modified.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html