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Date: Fri, 27 Nov 2015 04:22:39 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Tomas Winkler <tomas.winkler@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Subject: [bug] mei_fasync() bogosity
Message-ID: <20151127042237.GW22011@ZenIV.linux.org.uk>
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in "mei: implement fasync for event notification" a ->fasync() instance is
added as

static int mei_fasync(int fd, struct file *file, int band)
{

	struct mei_cl *cl = file->private_data;

	if (!mei_cl_is_connected(cl))
		return POLLERR;

	return fasync_helper(fd, file, band, &cl->ev_async);
}

Valid return values for ->fasync() are 0, 1 and -E...; 8 (aka POLLERR) is not.
What had been intended there?  -ENODEV?  Some other error?  As it is, the
thing is broken.