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authorPeter Hurley <peter@hurleysoftware.com>2014-06-16 09:17:02 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-10 16:05:19 -0700
commit9c9928bded9b4e35326d608b636ac65ff16f0404 (patch)
treedcfdc9255d7cde98c6efa579617f1bb945a42538
parentc590f6b6cf04513c755b65bbeaf7bd1e88203bb0 (diff)
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tty: Document locking for tty_port_hangup()
The tty lock is held when the tty driver's hangup() method is called (from the lone call-site, __tty_hangup()). The call-tree audit [1] of tty_port_hangup() is a closed graph of the callers of tty_port_hangup(); ie., all callers originate only from __tty_hangup(). Of these callers, none drop the tty lock prior to calling tty_port_hangup(). [1] Call-tree audit of tty_port_hangup() __tty_hangup() tty->ops->hangup() --+ | rs_hangup():arch/ia64/hp/sim/simserial.c line_hangup():arch/um/drivers/line.c gdm_tty_hangup():drivers/staging/gdm724x/gdm_tty.c fwtty_hangup():drivers/staging/fwserial/fwserial.c acm_tty_hangup():drivers/usb/class/cdc-acm.c serial_hangup():drivers/usb/serial/usb-serial.c ipoctal_hangup():drivers/ipack/devices/ipoctal.c cy_hangup():drivers/tty/cyclades.c isicom_hangup():drivers/tty/isicom.c rp_hangup():drivers/tty/rocket.c dashtty_hangup():drivers/tty/metag_da.c moxa_hangup():drivers/tty/moxa.c gsmtty_hangup():drivers/tty/n_gsm.c goldfish_tty_hangup():drivers/tty/goldfish.c ehv_bc_tty_hangup():drivers/tty/ehv_bytechan.c mxser_hangup():drivers/tty/mxser.c kgdb_nmi_tty_hangup():drivers/tty/serial/kgdb_nmi.c ifx_spi_hangup():drivers/tty/serial/ifx6x60.c ntty_hangup():drivers/tty/nozomi.c capinc_tty_hangup():drivers/isdn/capi/capi.c mgslpc_hangup():drivers/char/pcmcia/synclink_cs.c sdio_uart_hangup():drivers/mmc/card/sdio_uart.c rfcomm_tty_hangup():net/bluetooth/rfcomm/tty.c | +- tty_port_hangup() Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/tty_port.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 69e072b..7309594 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -227,6 +227,8 @@ out:
*
* Perform port level tty hangup flag and count changes. Drop the tty
* reference.
+ *
+ * Caller holds tty lock.
*/
void tty_port_hangup(struct tty_port *port)
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