LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Davide Libenzi <davidel@xmailserver.org>
To: Roland Dreier <rdreier@cisco.com>
Cc: Christoph Hellwig <hch@lst.de>,
	linux-fsdevel@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Avi Kivity <avi@qumranet.com>,
	kvm-devel@lists.sourceforge.net,
	Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@ftp.linux.org.uk>
Subject: Re: [PATCH/RFC 1/2] anon-inodes: Remove fd_install() from anon_inode_getfd()
Date: Thu, 28 Feb 2008 12:04:10 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0802281150060.7660@alien.or.mcafeemobile.com> (raw)
In-Reply-To: <adar6eyx8y5.fsf@cisco.com>

On Wed, 27 Feb 2008, Roland Dreier wrote:

>  > http://git.kernel.org/?p=linux/kernel/git/viro/vfs-2.6.git;a=commit;h=49be4f8114e6ff0efdab10ebba2493fb67bc3034
> 
> Actually, looking closer at the kvm changes here, I think that
> create_vcpu_fd() needs the same treatment as kvm_dev_ioctl_create_vm()
> gets in the patch because of the race I mentioned in the changelog
> for my patch: otherwise kvm_vcpu_release() could drop the last
> reference to vcpu->kvm->filp before the get_file() gets an extra
> reference.
> 
> I'm beginning to think that moving the fd_install() out of
> anon_inode_getfd() really is worth it to make a safer interface.

If we let the caller call fd_install(), then it may be messed up WRT 
cleanup (fd, file, inode).
How about removing the inode pointer handout altogether, and *doing* 
fd_install() inside anon_inode_getfd() like:

	if (pfile != NULL) {
		get_file(file);
		*pfile = file;
	}
	fd_install(fd, file);

In this way, if the caller want the file* back, he gets the reference 
bumped before fd_install().



- Davide



  parent reply	other threads:[~2008-02-28 20:04 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20080225191043.GA32342@lst.de>
2008-02-27 19:16 ` Roland Dreier
2008-02-27 19:18   ` [PATCH 2/2] IB/uverbs: Use anonymous inodes instead of private filesystem Roland Dreier
2008-02-27 19:20   ` [PATCH/RFC 1/2] anon-inodes: Remove fd_install() from anon_inode_getfd() Avi Kivity
2008-02-27 19:41   ` Davide Libenzi
2008-02-27 20:14     ` Roland Dreier
2008-02-27 20:30       ` Davide Libenzi
2008-02-27 21:05         ` Roland Dreier
2008-02-27 23:42           ` Roland Dreier
2008-02-28  7:52             ` Avi Kivity
2008-02-28 20:04             ` Davide Libenzi [this message]
2008-02-28 20:24               ` Roland Dreier
2008-02-28 20:52                 ` Davide Libenzi
2008-03-05  9:32                   ` [kvm-devel] " Avi Kivity
2008-03-06 15:14             ` Christoph Hellwig
2008-03-09  2:45               ` Roland Dreier
2008-03-17 10:40                 ` Christoph Hellwig
2008-03-17 10:48                   ` Avi Kivity
2008-03-09  2:46               ` Roland Dreier
2008-03-06 15:14   ` Al Viro

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Pine.LNX.4.64.0802281150060.7660@alien.or.mcafeemobile.com \
    --to=davidel@xmailserver.org \
    --cc=akpm@linux-foundation.org \
    --cc=avi@qumranet.com \
    --cc=hch@lst.de \
    --cc=kvm-devel@lists.sourceforge.net \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rdreier@cisco.com \
    --cc=viro@ftp.linux.org.uk \
    --subject='Re: [PATCH/RFC 1/2] anon-inodes: Remove fd_install() from anon_inode_getfd()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).