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Date: Tue, 3 Mar 2015 22:20:08 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Holler <holler@ahsoftware.de>,
        Richard Weinberger <richard.weinberger@gmail.com>,
        USB list <linux-usb@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, Felipe Balbi <balbi@ti.com>
Subject: Re: gadgetfs broken since 7f7f25e8
Message-ID: <20150303222007.GT29656@ZenIV.linux.org.uk>
References: <20150303083934.GR29656@ZenIV.linux.org.uk>
 <Pine.LNX.4.44L0.1503031042200.1655-100000@iolanthe.rowland.org>
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On Tue, Mar 03, 2015 at 10:47:14AM -0500, Alan Stern wrote:
> @@ -1279,6 +1284,9 @@ ep0_poll (struct file *fd, poll_table *w
>         struct dev_data         *dev = fd->private_data;
>         int                     mask = 0;
>  
> +	if (dev->state <= STATE_DEV_OPENED)
> +		return -ENODEV;
> +
>         poll_wait(fd, &dev->wait, wait);
>  
>         spin_lock_irq (&dev->lock);

That, BTW, is wrong.  ->poll() does *not* return negatives - to imitate
"we don't have ->poll()" we need it to return DEFAULT_POLLMASK.