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Message-Id: <11769658091138-git-send-email-ebiederm@xmission.com>
Date: Thu, 19 Apr 2007 00:55:53 -0600
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: "<Andrew Morton" <akpm@...l.org>
Cc: <containers@...ts.osdl.org>, Oleg Nesterov <oleg@...sign.ru>,
Christoph Hellwig <hch@...radead.org>,
<linux-kernel@...r.kernel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH] saa7134-tvaudio: Convert to kthread API.
From: Eric W. Biederman <ebiederm@...ssion.com> - unquoted
It is my goal to replace all kernel code that handles signals
from user space, calls kernel_thread or calls daemonize. All
of which the kthread_api makes unncessary. Handling signals
from user space is a maintenance problem becuase using a
kernel thread is an implementation detail and if user space
cares it does not allow us to change the implementation. Calling
daemonize is a problem because it has to undo a continually changing
set of state generated by user space, requiring the implemetation
to change continually. kernel_thread is a problem because it
returns a pid_t value. Numeric pids are inherently racy and
in the presence of a pid namespace they are no longer global
making them useless for general use in the kernel.
So this patch renames the pid member of struct saa7134_thread
started and changes it's type from pid_t to int. All it
has ever been used for is to detect if the kernel thread
is has been started so this works.
allow_signal(SIGTERM) and the calls to signal_pending have
been removed they are needed for the driver to operation.
The startup of tvaudio_thread and tvaudio_thread_dep have
been modified to use kthread_run instead of a combination
of kernel_thread and daemonize.
The result is code that is slightly simpler and more
maintainable.
Cc: Hartmut Hackmann <hartmut.hackmann@...nline.de>
Cc: Mauro Carvalho Chehab <mchehab@...radead.org>
Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
---
drivers/media/video/saa7134/saa7134-tvaudio.c | 27 ++++++++++++-------------
drivers/media/video/saa7134/saa7134.h | 2 +-
2 files changed, 14 insertions(+), 15 deletions(-)
diff --git a/drivers/media/video/saa7134/saa7134-tvaudio.c b/drivers/media/video/saa7134/saa7134-tvaudio.c
index 7b56041..b636cb1 100644
--- a/drivers/media/video/saa7134/saa7134-tvaudio.c
+++ b/drivers/media/video/saa7134/saa7134-tvaudio.c
@@ -27,6 +27,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/delay.h>
+#include <linux/kthread.h>
#include <asm/div64.h>
#include "saa7134-reg.h"
@@ -505,11 +506,9 @@ static int tvaudio_thread(void *data)
unsigned int i, audio, nscan;
int max1,max2,carrier,rx,mode,lastmode,default_carrier;
- daemonize("%s", dev->name);
- allow_signal(SIGTERM);
for (;;) {
tvaudio_sleep(dev,-1);
- if (dev->thread.shutdown || signal_pending(current))
+ if (dev->thread.shutdown)
goto done;
restart:
@@ -618,7 +617,7 @@ static int tvaudio_thread(void *data)
for (;;) {
if (tvaudio_sleep(dev,5000))
goto restart;
- if (dev->thread.shutdown || signal_pending(current))
+ if (dev->thread.shutdown)
break;
if (UNSET == dev->thread.mode) {
rx = tvaudio_getstereo(dev,&tvaudio[i]);
@@ -782,9 +781,6 @@ static int tvaudio_thread_ddep(void *data)
struct saa7134_dev *dev = data;
u32 value, norms, clock;
- daemonize("%s", dev->name);
- allow_signal(SIGTERM);
-
clock = saa7134_boards[dev->board].audio_clock;
if (UNSET != audio_clock_override)
clock = audio_clock_override;
@@ -796,7 +792,7 @@ static int tvaudio_thread_ddep(void *data)
for (;;) {
tvaudio_sleep(dev,-1);
- if (dev->thread.shutdown || signal_pending(current))
+ if (dev->thread.shutdown)
goto done;
restart:
@@ -986,14 +982,17 @@ int saa7134_tvaudio_init2(struct saa7134_dev *dev)
break;
}
- dev->thread.pid = -1;
+ dev->thread.started = 0;
if (my_thread) {
+ struct task_struct *task;
/* start tvaudio thread */
init_waitqueue_head(&dev->thread.wq);
init_completion(&dev->thread.exit);
- dev->thread.pid = kernel_thread(my_thread,dev,0);
- if (dev->thread.pid < 0)
- printk(KERN_WARNING "%s: kernel_thread() failed\n",
+ task = kthread_run(my_thread, dev, "%s", dev->name);
+ if (!IS_ERR(task))
+ dev->thread.started = 1;
+ else
+ printk(KERN_WARNING "%s: kthread_create() failed\n",
dev->name);
saa7134_tvaudio_do_scan(dev);
}
@@ -1005,7 +1004,7 @@ int saa7134_tvaudio_init2(struct saa7134_dev *dev)
int saa7134_tvaudio_fini(struct saa7134_dev *dev)
{
/* shutdown tvaudio thread */
- if (dev->thread.pid >= 0) {
+ if (dev->thread.started) {
dev->thread.shutdown = 1;
wake_up_interruptible(&dev->thread.wq);
wait_for_completion(&dev->thread.exit);
@@ -1020,7 +1019,7 @@ int saa7134_tvaudio_do_scan(struct saa7134_dev *dev)
dprintk("sound IF not in use, skipping scan\n");
dev->automute = 0;
saa7134_tvaudio_setmute(dev);
- } else if (dev->thread.pid >= 0) {
+ } else if (dev->thread.started) {
dev->thread.mode = UNSET;
dev->thread.scan2++;
wake_up_interruptible(&dev->thread.wq);
diff --git a/drivers/media/video/saa7134/saa7134.h b/drivers/media/video/saa7134/saa7134.h
index 62224cc..3a10ce7 100644
--- a/drivers/media/video/saa7134/saa7134.h
+++ b/drivers/media/video/saa7134/saa7134.h
@@ -324,7 +324,7 @@ struct saa7134_pgtable {
/* tvaudio thread status */
struct saa7134_thread {
- pid_t pid;
+ int started;
struct completion exit;
wait_queue_head_t wq;
unsigned int shutdown;
--
1.5.0.g53756
-
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