From: Peter Hurley <peter@hurleysoftware.com>
Date: Mon, 11 Mar 2013 20:44:40 +0000 (-0400)
Subject: tty: Separate release semantics of ldisc reference
X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~136^2~56
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ebc9baed42e42f9b51cf61672b7afb72f068d523;p=pandora-kernel.git

tty: Separate release semantics of ldisc reference

tty_ldisc_ref()/tty_ldisc_unref() have usage semantics
equivalent to down_read_trylock()/up_read(). Only
callers of tty_ldisc_put() are performing the additional
operations necessary for proper ldisc teardown, and then only
after ensuring no outstanding 'read lock' remains.

Thus, tty_ldisc_unref() should never be the last reference;
WARN if it is. Conversely, tty_ldisc_put() should never be
destructing if the use count != 1.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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