Re: [PATCH] afs: use kthread_ API

From: Christoph Hellwig
Date: Tue Feb 14 2006 - 13:24:00 EST

On Tue, Feb 14, 2006 at 06:22:09PM +0000, David Howells wrote:
> Christoph Hellwig <hch@xxxxxx> wrote:
>
> > Use the kthread_ API instead of opencoding lots of hairy code for kernel
> > thread creation and teardown.
>
> NAK. The kthread API appears nowhere in the patch.

Sorry, I accidentally attached a different afs patch. Here's the
correct one:


Index: linux-2.6/fs/afs/cmservice.c
===================================================================
--- linux-2.6.orig/fs/afs/cmservice.c 2006-01-11 11:55:42.000000000 +0100
+++ linux-2.6/fs/afs/cmservice.c 2006-02-10 14:27:05.000000000 +0100
@@ -13,6 +13,7 @@
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
+#include <linux/kthread.h>
#include "server.h"
#include "cell.h"
#include "transport.h"
@@ -97,14 +98,11 @@
.ops_end = &AFSCM_ops[sizeof(AFSCM_ops) / sizeof(AFSCM_ops[0])],
};

-static DECLARE_COMPLETION(kafscmd_alive);
-static DECLARE_COMPLETION(kafscmd_dead);
-static DECLARE_WAIT_QUEUE_HEAD(kafscmd_sleepq);
+static struct task_struct *kafscmd_thread;
static LIST_HEAD(kafscmd_attention_list);
static LIST_HEAD(afscm_calls);
static DEFINE_SPINLOCK(afscm_calls_lock);
static DEFINE_SPINLOCK(kafscmd_attention_lock);
-static int kafscmd_die;

/*****************************************************************************/
/*
@@ -112,39 +110,31 @@
*/
static int kafscmd(void *arg)
{
- DECLARE_WAITQUEUE(myself, current);
-
struct rxrpc_call *call;
_SRXAFSCM_xxxx_t func;
int die;

printk(KERN_INFO "kAFS: Started kafscmd %d\n", current->pid);

- daemonize("kafscmd");
-
- complete(&kafscmd_alive);
-
/* loop around looking for things to attend to */
do {
if (list_empty(&kafscmd_attention_list)) {
set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&kafscmd_sleepq, &myself);

for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (!list_empty(&kafscmd_attention_list) ||
signal_pending(current) ||
- kafscmd_die)
+ kthread_should_stop())
break;

schedule();
}

- remove_wait_queue(&kafscmd_sleepq, &myself);
set_current_state(TASK_RUNNING);
}

- die = kafscmd_die;
+ die = kthread_should_stop();

/* dequeue the next call requiring attention */
call = NULL;
@@ -175,9 +165,7 @@

} while(!die);

- /* and that's all */
- complete_and_exit(&kafscmd_dead, 0);
-
+ return 0;
} /* end kafscmd() */

/*****************************************************************************/
@@ -223,7 +211,7 @@

spin_unlock(&kafscmd_attention_lock);

- wake_up(&kafscmd_sleepq);
+ wake_up_process(kafscmd_thread);

_leave(" {u=%d}", atomic_read(&call->usage));
} /* end afscm_attention() */
@@ -263,7 +251,7 @@
if (removed)
rxrpc_put_call(call);

- wake_up(&kafscmd_sleepq);
+ wake_up_process(kafscmd_thread);

_leave("");
} /* end afscm_error() */
@@ -297,11 +285,11 @@

down_write(&afscm_sem);
if (!afscm_usage) {
- ret = kernel_thread(kafscmd, NULL, 0);
- if (ret < 0)
+ kafscmd_thread = kthread_run(kafscmd, NULL, "kafscmd");
+ if (IS_ERR(kafscmd_thread)) {
+ ret = PTR_ERR(kafscmd_thread);
goto out;
-
- wait_for_completion(&kafscmd_alive);
+ }

ret = rxrpc_add_service(afs_transport, &AFSCM_service);
if (ret < 0)
@@ -317,10 +305,7 @@
return 0;

kill:
- kafscmd_die = 1;
- wake_up(&kafscmd_sleepq);
- wait_for_completion(&kafscmd_dead);
-
+ kthread_stop(kafscmd_thread);
out:
up_write(&afscm_sem);
return ret;
@@ -369,10 +354,7 @@
}
spin_unlock(&afscm_calls_lock);

- /* get rid of my daemon */
- kafscmd_die = 1;
- wake_up(&kafscmd_sleepq);
- wait_for_completion(&kafscmd_dead);
+ kthread_stop(kafscmd_thread);

/* dispose of any calls waiting for attention */
spin_lock(&kafscmd_attention_lock);
Index: linux-2.6/fs/afs/kafsasyncd.c
===================================================================
--- linux-2.6.orig/fs/afs/kafsasyncd.c 2005-12-27 18:30:31.000000000 +0100
+++ linux-2.6/fs/afs/kafsasyncd.c 2006-02-10 14:35:37.000000000 +0100
@@ -20,6 +20,7 @@
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
+#include <linux/kthread.h>
#include "cell.h"
#include "server.h"
#include "volume.h"
@@ -29,11 +30,8 @@
#include <asm/errno.h>
#include "internal.h"

-static DECLARE_COMPLETION(kafsasyncd_alive);
-static DECLARE_COMPLETION(kafsasyncd_dead);
-static DECLARE_WAIT_QUEUE_HEAD(kafsasyncd_sleepq);
+
static struct task_struct *kafsasyncd_task;
-static int kafsasyncd_die;

static int kafsasyncd(void *arg);

@@ -55,15 +53,10 @@
*/
int afs_kafsasyncd_start(void)
{
- int ret;
-
- ret = kernel_thread(kafsasyncd, NULL, 0);
- if (ret < 0)
- return ret;
-
- wait_for_completion(&kafsasyncd_alive);
-
- return ret;
+ kafsasyncd_task = kthread_run(kafsasyncd, NULL, "kafsasyncd");
+ if (IS_ERR(kafsasyncd_task))
+ return PTR_ERR(kafsasyncd_task);
+ return 0;
} /* end afs_kafsasyncd_start() */

/*****************************************************************************/
@@ -72,11 +65,7 @@
*/
void afs_kafsasyncd_stop(void)
{
- /* get rid of my daemon */
- kafsasyncd_die = 1;
- wake_up(&kafsasyncd_sleepq);
- wait_for_completion(&kafsasyncd_dead);
-
+ kthread_stop(kafsasyncd_task);
} /* end afs_kafsasyncd_stop() */

/*****************************************************************************/
@@ -88,32 +77,22 @@
struct afs_async_op *op;
int die;

- DECLARE_WAITQUEUE(myself, current);
-
- kafsasyncd_task = current;
-
printk("kAFS: Started kafsasyncd %d\n", current->pid);

- daemonize("kafsasyncd");
-
- complete(&kafsasyncd_alive);
-
/* loop around looking for things to attend to */
do {
set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&kafsasyncd_sleepq, &myself);

for (;;) {
if (!list_empty(&kafsasyncd_async_attnq) ||
signal_pending(current) ||
- kafsasyncd_die)
+ kthread_should_stop())
break;

schedule();
set_current_state(TASK_INTERRUPTIBLE);
}

- remove_wait_queue(&kafsasyncd_sleepq, &myself);
set_current_state(TASK_RUNNING);

try_to_freeze();
@@ -121,7 +100,7 @@
/* discard pending signals */
afs_discard_my_signals();

- die = kafsasyncd_die;
+ die = kthread_should_stop();

/* deal with the next asynchronous operation requiring
* attention */
@@ -156,7 +135,6 @@

/* need to kill all outstanding asynchronous operations before
* exiting */
- kafsasyncd_task = NULL;
spin_lock(&kafsasyncd_async_lock);

/* fold the busy and attention queues together */
@@ -186,8 +164,7 @@

/* and that's all */
_leave("");
- complete_and_exit(&kafsasyncd_dead, 0);
-
+ return 0;
} /* end kafsasyncd() */

/*****************************************************************************/
@@ -228,7 +205,7 @@

spin_unlock(&kafsasyncd_async_lock);

- wake_up(&kafsasyncd_sleepq);
+ wake_up_process(kafsasyncd_task);

_leave("");
} /* end afs_kafsasyncd_attend_op() */
@@ -251,7 +228,7 @@

spin_unlock(&kafsasyncd_async_lock);

- wake_up(&kafsasyncd_sleepq);
+ wake_up_process(kafsasyncd_task);

_leave("");
} /* end afs_kafsasyncd_terminate_op() */
Index: linux-2.6/fs/afs/kafstimod.c
===================================================================
--- linux-2.6.orig/fs/afs/kafstimod.c 2005-12-27 18:30:31.000000000 +0100
+++ linux-2.6/fs/afs/kafstimod.c 2006-02-10 14:31:41.000000000 +0100
@@ -13,16 +13,14 @@
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
+#include <linux/kthread.h>
#include "cell.h"
#include "volume.h"
#include "kafstimod.h"
#include <asm/errno.h>
#include "internal.h"

-static DECLARE_COMPLETION(kafstimod_alive);
-static DECLARE_COMPLETION(kafstimod_dead);
-static DECLARE_WAIT_QUEUE_HEAD(kafstimod_sleepq);
-static int kafstimod_die;
+static struct task_struct *kafstimod_thread;

static LIST_HEAD(kafstimod_list);
static DEFINE_SPINLOCK(kafstimod_lock);
@@ -35,15 +33,11 @@
*/
int afs_kafstimod_start(void)
{
- int ret;
+ kafstimod_thread = kthread_run(kafstimod, NULL, "kafstimod");
+ if (IS_ERR(kafstimod_thread))
+ return PTR_ERR(kafstimod_thread);

- ret = kernel_thread(kafstimod, NULL, 0);
- if (ret < 0)
- return ret;
-
- wait_for_completion(&kafstimod_alive);
-
- return ret;
+ return 0;
} /* end afs_kafstimod_start() */

/*****************************************************************************/
@@ -52,11 +46,7 @@
*/
void afs_kafstimod_stop(void)
{
- /* get rid of my daemon */
- kafstimod_die = 1;
- wake_up(&kafstimod_sleepq);
- wait_for_completion(&kafstimod_dead);
-
+ kthread_stop(kafstimod_thread);
} /* end afs_kafstimod_stop() */

/*****************************************************************************/
@@ -67,28 +57,20 @@
{
struct afs_timer *timer;

- DECLARE_WAITQUEUE(myself, current);
-
printk("kAFS: Started kafstimod %d\n", current->pid);

- daemonize("kafstimod");
-
- complete(&kafstimod_alive);
-
/* loop around looking for things to attend to */
loop:
set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&kafstimod_sleepq, &myself);

for (;;) {
unsigned long jif;
signed long timeout;

/* deal with the server being asked to die */
- if (kafstimod_die) {
- remove_wait_queue(&kafstimod_sleepq, &myself);
+ if (kthread_should_stop()) {
_leave("");
- complete_and_exit(&kafstimod_dead, 0);
+ return 0;
}

try_to_freeze();
@@ -126,7 +108,6 @@
* entry
*/
immediate:
- remove_wait_queue(&kafstimod_sleepq, &myself);
set_current_state(TASK_RUNNING);

_debug("@@@ Begin Timeout of %p", timer);
@@ -172,7 +153,7 @@

spin_unlock(&kafstimod_lock);

- wake_up(&kafstimod_sleepq);
+ wake_up_process(kafstimod_thread);

_leave("");
} /* end afs_kafstimod_add_timer() */
@@ -197,7 +178,7 @@

spin_unlock(&kafstimod_lock);

- wake_up(&kafstimod_sleepq);
+ wake_up_process(kafstimod_thread);

_leave(" = %d", ret);
return ret;
-
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