[Devel] Re: [PATCH/RFC] kthread API conversion for dvb_frontend and av7110

[Cedric Le Goater]

Cedric Le Goater wrote:
> Andrew de Quincey wrote:
> 
>> Hi - the conversion looks good to me.. I can't really offer any more 
>> constructive suggestions beyond what Cedric has already said. 
> 
> ok. so, should we just resend a refreshed version of the patch when 2.6.19
> comes out ?  
> 
>> Theres another thread in dvb_ca_en50221.c that could be converted as well 
>> though, hint hint ;)
> 
> ok ok :) i'll look at it ...

Here's a try. Compiles and boots but I have no hardware to test the
patch :( 

could we replace wait_event_interruptible_timeout() with  
wait_event_timeout() ? I don't see who would signal the thread.

thanks,

C.


Signed-off-by: Cedric Le Goater <clg at fr.ibm.com>
---
 drivers/media/dvb/dvb-core/dvb_ca_en50221.c |   59 ++++++++--------------------
 1 file changed, 18 insertions(+), 41 deletions(-)

Index: 2.6.20-rc4-mm1/drivers/media/dvb/dvb-core/dvb_ca_en50221.c
===================================================================
--- 2.6.20-rc4-mm1.orig/drivers/media/dvb/dvb-core/dvb_ca_en50221.c
+++ 2.6.20-rc4-mm1/drivers/media/dvb/dvb-core/dvb_ca_en50221.c
@@ -37,6 +37,7 @@
 #include <linux/delay.h>
 #include <linux/spinlock.h>
 #include <linux/sched.h>
+#include <linux/kthread.h>
 
 #include "dvb_ca_en50221.h"
 #include "dvb_ringbuffer.h"
@@ -140,14 +141,11 @@ struct dvb_ca_private {
 	wait_queue_head_t wait_queue;
 
 	/* PID of the monitoring thread */
-	pid_t thread_pid;
+	struct task_struct* thread;
 
 	/* Wait queue used when shutting thread down */
 	wait_queue_head_t thread_queue;
 
-	/* Flag indicating when thread should exit */
-	unsigned int exit:1;
-
 	/* Flag indicating if the CA device is open */
 	unsigned int open:1;
 
@@ -916,8 +914,6 @@ static int dvb_ca_en50221_thread_should_
 		ca->wakeup = 0;
 		return 1;
 	}
-	if (ca->exit)
-		return 1;
 
 	return 0;
 }
@@ -982,7 +978,6 @@ static void dvb_ca_en50221_thread_update
 static int dvb_ca_en50221_thread(void *data)
 {
 	struct dvb_ca_private *ca = data;
-	char name[15];
 	int slot;
 	int flags;
 	int status;
@@ -991,28 +986,19 @@ static int dvb_ca_en50221_thread(void *d
 
 	dprintk("%s\n", __FUNCTION__);
 
-	/* setup kernel thread */
-	snprintf(name, sizeof(name), "kdvb-ca-%i:%i", ca->dvbdev->adapter->num, ca->dvbdev->id);
-
-	lock_kernel();
-	daemonize(name);
-	sigfillset(&current->blocked);
-	unlock_kernel();
-
 	/* choose the correct initial delay */
 	dvb_ca_en50221_thread_update_delay(ca);
 
 	/* main loop */
-	while (!ca->exit) {
+	while (1) {
 		/* sleep for a bit */
 		if (!ca->wakeup) {
-			flags = wait_event_interruptible_timeout(ca->thread_queue,
-								 dvb_ca_en50221_thread_should_wakeup(ca),
-								 ca->delay);
-			if ((flags == -ERESTARTSYS) || ca->exit) {
-				/* got signal or quitting */
+			flags = wait_event_interruptible_timeout(
+				ca->thread_queue,
+				dvb_ca_en50221_thread_should_wakeup(ca) || kthread_should_stop(),
+				ca->delay);
+			if ((flags == -ERESTARTSYS) || kthread_should_stop())
 				break;
-			}
 		}
 		ca->wakeup = 0;
 
@@ -1182,9 +1168,8 @@ static int dvb_ca_en50221_thread(void *d
 	}
 
 	/* completed */
-	ca->thread_pid = 0;
+	ca->thread = NULL;
 	mb();
-	wake_up_interruptible(&ca->thread_queue);
 	return 0;
 }
 
@@ -1663,6 +1648,7 @@ int dvb_ca_en50221_init(struct dvb_adapt
 	int ret;
 	struct dvb_ca_private *ca = NULL;
 	int i;
+	struct task_struct *thread;
 
 	dprintk("%s\n", __FUNCTION__);
 
@@ -1682,9 +1668,8 @@ int dvb_ca_en50221_init(struct dvb_adapt
 		goto error;
 	}
 	init_waitqueue_head(&ca->wait_queue);
-	ca->thread_pid = 0;
+	ca->thread = NULL;
 	init_waitqueue_head(&ca->thread_queue);
-	ca->exit = 0;
 	ca->open = 0;
 	ca->wakeup = 0;
 	ca->next_read_slot = 0;
@@ -1711,13 +1696,14 @@ int dvb_ca_en50221_init(struct dvb_adapt
 
 	/* create a kthread for monitoring this CA device */
 
-	ret = kernel_thread(dvb_ca_en50221_thread, ca, 0);
-
-	if (ret < 0) {
+	thread = kthread_run(dvb_ca_en50221_thread, ca, "kdvb-ca-%i:%i",
+			     ca->dvbdev->adapter->num, ca->dvbdev->id);
+	if (IS_ERR(thread)) {
+		ret = PTR_ERR(thread);
 		printk("dvb_ca_init: failed to start kernel_thread (%d)\n", ret);
 		goto error;
 	}
-	ca->thread_pid = ret;
+	ca->thread = thread;
 	return 0;
 
 error:
@@ -1748,17 +1734,8 @@ void dvb_ca_en50221_release(struct dvb_c
 	dprintk("%s\n", __FUNCTION__);
 
 	/* shutdown the thread if there was one */
-	if (ca->thread_pid) {
-		if (kill_proc(ca->thread_pid, 0, 1) == -ESRCH) {
-			printk("dvb_ca_release adapter %d: thread PID %d already died\n",
-			       ca->dvbdev->adapter->num, ca->thread_pid);
-		} else {
-			ca->exit = 1;
-			mb();
-			dvb_ca_en50221_thread_wakeup(ca);
-			wait_event_interruptible(ca->thread_queue, ca->thread_pid == 0);
-		}
-	}
+	if (ca->thread)
+		kthread_stop(ca->thread);
 
 	for (i = 0; i < ca->slot_count; i++) {
 		dvb_ca_en50221_slot_shutdown(ca, i);
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