Date: Tue, 22 May 2007 01:18:51 +0100
From: Al Viro <viro@ftp.linux.org.uk>
To: akpm@linux-foundation.org
Cc: mm-commits@vger.kernel.org, kenchen@google.com, viro@zeniv.linux.org.uk,
       linux-kernel@vger.kernel.org
Subject: Re: + loop-preallocate-eight-loop-devices.patch added to -mm tree
Message-ID: <20070522001851.GE4095@ftp.linux.org.uk>
References: <200705212200.l4LM0tYK021050@shell0.pdx.osdl.net>
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On Mon, May 21, 2007 at 03:00:55PM -0700, akpm@linux-foundation.org wrote:
> +	if (register_blkdev(LOOP_MAJOR, "loop"))
> +		return -EIO;
> +	blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
> +				  THIS_MODULE, loop_probe, NULL, NULL);
> +
> +	for (i = 0; i < nr; i++) {
> +		if (!loop_init_one(i))
> +			goto err;
> +	}
> +
> +	printk(KERN_INFO "loop: module loaded\n");
> +	return 0;
> +err:
> +	loop_exit();

This isn't good.  You *can't* fail once a single disk has been registered.
Anyone could've opened it by now.

IOW, you need to
	* register region *after* you are past the point of no return
	* either not fail on failing loop_init_one() here, or separate
allocations and actual add_disk().
-
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