tty: Separate release semantics of ldisc reference

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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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Peter Hurley 2013-03-11 16:44:40 -04:00 • committed by Greg Kroah-Hartman

parent 8842dda236

commit ebc9baed42

1 changed files with 35 additions and 34 deletions

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drivers/tty/tty_ldisc.c

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