ser_gigaset: convert mutex to completion

The ser_gigaset ISDN driver was using a mutex in its close() method for
waiting for other running ldisc methods to finish.  That's what completions
are for.  Incidentally, this also avoids a spurious "BUG: lock held at task
exit time" message when the driver's userspace daemon daemonizes itself.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Tilman Schmidt 2008-02-06 01:38:30 -08:00 committed by Linus Torvalds
parent e468c04894
commit ee51ef0ecb

View File

@ -17,6 +17,7 @@
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/poll.h>
#include <linux/completion.h>
/* Version Information */
#define DRIVER_AUTHOR "Tilman Schmidt"
@ -48,7 +49,7 @@ struct ser_cardstate {
struct platform_device dev;
struct tty_struct *tty;
atomic_t refcnt;
struct mutex dead_mutex;
struct completion dead_cmp;
};
static struct platform_driver device_driver = {
@ -498,7 +499,7 @@ static struct cardstate *cs_get(struct tty_struct *tty)
static void cs_put(struct cardstate *cs)
{
if (atomic_dec_and_test(&cs->hw.ser->refcnt))
mutex_unlock(&cs->hw.ser->dead_mutex);
complete(&cs->hw.ser->dead_cmp);
}
/*
@ -527,8 +528,8 @@ gigaset_tty_open(struct tty_struct *tty)
cs->dev = &cs->hw.ser->dev.dev;
cs->hw.ser->tty = tty;
mutex_init(&cs->hw.ser->dead_mutex);
atomic_set(&cs->hw.ser->refcnt, 1);
init_completion(&cs->hw.ser->dead_cmp);
tty->disc_data = cs;
@ -543,7 +544,6 @@ gigaset_tty_open(struct tty_struct *tty)
}
gig_dbg(DEBUG_INIT, "Startup of HLL done");
mutex_lock(&cs->hw.ser->dead_mutex);
return 0;
error:
@ -577,7 +577,7 @@ gigaset_tty_close(struct tty_struct *tty)
else {
/* wait for running methods to finish */
if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
mutex_lock(&cs->hw.ser->dead_mutex);
wait_for_completion(&cs->hw.ser->dead_cmp);
}
/* stop operations */