Date: Mon, 27 Aug 2007 23:59:01 +0100
From: Alasdair G Kergon <agk@redhat.com>
To: Al Viro <viro@ftp.linux.org.uk>
Cc: linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-fsdevel@vger.kernel.org, axboe@kernel.dk
Subject: Re: [RFC] block_device_operations prototype changes
Message-ID: <20070827225901.GB30122@agk.fab.redhat.com>
Mail-Followup-To: Al Viro <viro@ftp.linux.org.uk>,
	linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, axboe@kernel.dk
References: <20070827103053.GF21089@ftp.linux.org.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20070827103053.GF21089@ftp.linux.org.uk>
User-Agent: Mutt/1.4.1i
Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE.
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 954
Lines: 30

On Mon, Aug 27, 2007 at 11:30:53AM +0100, Al Viro wrote:
> 3) ->ioctl().  What a mess...  

Yup.

See also:
  Subject: [PATCH] dm: support ioctls on mapped devices: fix with fake file
  http://uwsg.indiana.edu/hypermail/linux/kernel/0606.2/2979.html

and related threads.

> First of all, we have 3 methods with different
> calling conventions:
> 	->ioctl(inode, file, cmd, arg)
> 	->unlocked_ioctl(inode, file, cmd, arg)

When I last looked it was:
  long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
with the lack of inode forcing dm to use ->ioctl (because file can be NULL when
only the block device is known) and immediately drop the pointless-for-us
lock!

Alasdair
-- 
agk@redhat.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/