diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-06-16 09:17:01 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-10 16:05:19 -0700 |
| commit | c590f6b6cf04513c755b65bbeaf7bd1e88203bb0 (patch) | |
| tree | 786b7f83df2e7a1ed5462c914d759927427d33cf /drivers/tty/tty_port.c | |
| parent | addd4672bb442b23d16f91c5bae866ba1f9ffd4c (diff) | |
tty: Document locking for tty_port_block_til_ready()
The tty lock is held when the tty driver's open() method is called
(from tty_open()). The call-tree audit [1] of tty_port_block_til_ready()
is a closed graph of the callers of tty_port_block_til_ready();
ie., all callers originate only from tty_open().
Of these callers, none drop the tty lock.
Also, document tty_port_block_til_ready() may drop and reacquire
the tty lock when blocking, which means the tty or tty_port may have
changed state.
[1]
Call-tree audit of tty_port_block_til_ready()
* does not include call tree of tty_port_open() which is already
documented in 'tty: Document locking from tty_port_open()'
tty_open()
tty->ops->open() --+
|
cy_open():drivers/tty/cyclades.c
rp_open():drivers/tty/rocket.c
rs_open():drivers/tty/amiserial.c
moxa_open():drivers/tty/moxa.c
gsmtty_open():drivers/tty/n_gsm.c
rs_open():drivers/tty/serial/68328serial.c
uart_open():drivers/tty/serial/serial_core.c
isdn_tty_open():drivers/isdn/i4l/isdn_tty.c
mgslpc_open():drivers/char/pcmcia/synclink_cs.c
|
+- tty_port_block_til_ready()
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_port.c')
| -rw-r--r-- | drivers/tty/tty_port.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index f4698696abae..69e072b59127 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -348,6 +348,11 @@ EXPORT_SYMBOL(tty_port_lower_dtr_rts); * do carrier detect and the dtr_rts method if it supports software * management of these lines. Note that the dtr/rts raise is done each * iteration as a hangup may have previously dropped them while we wait. + * + * Caller holds tty lock. + * + * NB: May drop and reacquire tty lock when blocking, so tty and tty_port + * may have changed state (eg., may have been hung up). */ int tty_port_block_til_ready(struct tty_port *port, |