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Commit ee51ef0e authored by Tilman Schmidt's avatar Tilman Schmidt Committed by Linus Torvalds
Browse files

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: default avatarTilman Schmidt <tilman@imap.cc>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e468c048

drivers/isdn/gigaset/ser-gigaset.c

+5 −5
Original line number Diff line number Diff line
@@ -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 */