Messages in this thread |  | | Date | Thu, 13 Feb 2014 10:36:16 -0800 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 04/24] tty: Fix ref counting for port krefs |
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On Sun, Feb 09, 2014 at 08:59:04PM -0500, Peter Hurley wrote: > The tty core supports two models for handling tty_port lifetimes; > the tty_port can use the kref supplied by tty_port (which will > automatically destruct the tty_port when the ref count drops to > zero) or it can destruct the tty_port manually. > > For tty drivers that choose to use the port kref to manage the > tty_port lifetime, it is not possible to safely acquire a port > reference conditionally. If the last reference is released after > evaluating the condition but before acquiring the reference, a > bogus reference will be held while the tty_port destruction > commences. > > Rather, only acquire a port reference if the ref count is non-zero > and allow the caller to distinguish if a reference has successfully > been acquired. > > Cc: Jiri Slaby <jslaby@suse.cz> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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