[PATCH] w1: use kthread api.

This patch removes old-style kernel thread initialization
and changes w1 to use kthread api.
It is based on Christoph Hellwig <hch@lst.de> work.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 28 insertions, 65 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index d640c1e1f8cd..a698b517e863 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -30,6 +30,7 @@
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/kthread.h>
 
 #include <asm/atomic.h>
 
@@ -57,9 +58,7 @@ module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
 DEFINE_SPINLOCK(w1_mlock);
 LIST_HEAD(w1_masters);
 
-static pid_t control_thread;
-static int control_needs_exit;
-static DECLARE_COMPLETION(w1_control_complete);
+static struct task_struct *w1_control_thread;
 
 static int w1_master_match(struct device *dev, struct device_driver *drv)
 {
@@ -717,22 +716,16 @@ static int w1_control(void *data)
 {
         struct w1_slave *sl, *sln;
         struct w1_master *dev, *n;
-        int err, have_to_wait = 0;
+        int have_to_wait = 0;
 
-        daemonize("w1_control");
-        allow_signal(SIGTERM);
-
-        while (!control_needs_exit || have_to_wait) {
+        while (!kthread_should_stop() || have_to_wait) {
                 have_to_wait = 0;
 
                 try_to_freeze();
                 msleep_interruptible(w1_control_timeout * 1000);
 
-                if (signal_pending(current))
-                        flush_signals(current);
-
                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
-                        if (!control_needs_exit && !dev->flags)
+                        if (!kthread_should_stop() && !dev->flags)
                                 continue;
                         /*
                          * Little race: we can create thread but not set the flag.
@@ -743,21 +736,12 @@ static int w1_control(void *data)
                                 continue;
                         }
 
-                        if (control_needs_exit) {
+                        if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 
-                                err = kill_proc(dev->kpid, SIGTERM, 1);
-                                if (err)
-                                        dev_err(&dev->dev,
-                                                 "Failed to send signal to w1 kernel thread %d.\n",
-                                                 dev->kpid);
-                        }
-
-                        if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
-                                wait_for_completion(&dev->dev_exited);
-                                spin_lock_bh(&w1_mlock);
+                                spin_lock(&w1_mlock);
                                 list_del(&dev->w1_master_entry);
-                                spin_unlock_bh(&w1_mlock);
+                                spin_unlock(&w1_mlock);
 
                                 down(&dev->mutex);
                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
@@ -789,7 +773,7 @@ static int w1_control(void *data)
                 }
         }
 
-        complete_and_exit(&w1_control_complete, 0);
+        return 0;
 }
 
 int w1_process(void *data)
@@ -797,17 +781,11 @@ int w1_process(void *data)
         struct w1_master *dev = (struct w1_master *) data;
         struct w1_slave *sl, *sln;
 
-        daemonize("%s", dev->name);
-        allow_signal(SIGTERM);
-
-        while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
+        while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
                 try_to_freeze();
                 msleep_interruptible(w1_timeout * 1000);
 
-                if (signal_pending(current))
-                        flush_signals(current);
-
-                if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
+                if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
                         break;
 
                 if (!dev->initialized)
@@ -840,7 +818,6 @@ int w1_process(void *data)
         }
 
         atomic_dec(&dev->refcnt);
-        complete_and_exit(&dev->dev_exited, 0);
 
         return 0;
 }
@@ -873,11 +850,11 @@ static int w1_init(void)
                 goto err_out_master_unregister;
         }
 
-        control_thread = kernel_thread(&w1_control, NULL, 0);
-        if (control_thread < 0) {
+        w1_control_thread = kthread_run(w1_control, NULL, "w1_control");
+        if (IS_ERR(w1_control_thread)) {
+                retval = PTR_ERR(w1_control_thread);
                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
-                        control_thread);
-                retval = control_thread;
+                        retval);
                 goto err_out_slave_unregister;
         }
 
@@ -903,8 +880,7 @@ static void w1_fini(void)
         list_for_each_entry(dev, &w1_masters, w1_master_entry)
                 __w1_remove_master_device(dev);
 
-        control_needs_exit = 1;
-        wait_for_completion(&w1_control_complete);
+        kthread_stop(w1_control_thread);
 
         driver_unregister(&w1_slave_driver);
         driver_unregister(&w1_master_driver);
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 5f09213512bf..56980505e6c4 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -172,12 +172,11 @@ struct w1_master
 
         long                    flags;
 
-        pid_t                   kpid;
+        struct task_struct      *thread;
         struct semaphore        mutex;
 
         struct device_driver    *driver;
         struct device           dev;
-        struct completion       dev_exited;
 
         struct w1_bus_master    *bus_master;
 
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index a2f9065e1928..68565aacec7b 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -22,6 +22,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/delay.h>
+#include <linux/kthread.h>
 
 #include "w1.h"
 #include "w1_log.h"
@@ -56,7 +57,6 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
         dev->max_slave_count    = slave_count;
         dev->slave_count        = 0;
         dev->attempts           = 0;
-        dev->kpid               = -1;
         dev->initialized        = 0;
         dev->id                 = id;
         dev->slave_ttl          = slave_ttl;
@@ -67,8 +67,6 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
         INIT_LIST_HEAD(&dev->slist);
         init_MUTEX(&dev->mutex);
 
-        init_completion(&dev->dev_exited);
-
         memcpy(&dev->dev, device, sizeof(struct device));
         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
                   "w1_bus_master%u", dev->id);
@@ -116,12 +114,12 @@ int w1_add_master_device(struct w1_bus_master *master)
         if (!dev)
                 return -ENOMEM;
 
-        dev->kpid = kernel_thread(&w1_process, dev, 0);
-        if (dev->kpid < 0) {
+        dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
+        if (IS_ERR(dev->thread)) {
+                retval = PTR_ERR(dev->thread);
                 dev_err(&dev->dev,
                          "Failed to create new kernel thread. err=%d\n",
-                         dev->kpid);
-                retval = dev->kpid;
+                         retval);
                 goto err_out_free_dev;
         }
 
@@ -138,20 +136,14 @@ int w1_add_master_device(struct w1_bus_master *master)
         spin_unlock(&w1_mlock);
 
         msg.id.mst.id = dev->id;
-        msg.id.mst.pid = dev->kpid;
+        msg.id.mst.pid = dev->thread->pid;
         msg.type = W1_MASTER_ADD;
         w1_netlink_send(dev, &msg);
 
         return 0;
 
 err_out_kill_thread:
-        set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
-        if (kill_proc(dev->kpid, SIGTERM, 1))
-                dev_err(&dev->dev,
-                         "Failed to send signal to w1 kernel thread %d.\n",
-                         dev->kpid);
-        wait_for_completion(&dev->dev_exited);
-
+        kthread_stop(dev->thread);
 err_out_free_dev:
         w1_free_dev(dev);
 
@@ -160,18 +152,14 @@ err_out_free_dev:
 
 void __w1_remove_master_device(struct w1_master *dev)
 {
-        int err;
         struct w1_netlink_msg msg;
+        pid_t pid = dev->thread->pid;
 
         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
-        err = kill_proc(dev->kpid, SIGTERM, 1);
-        if (err)
-                dev_err(&dev->dev,
-                         "%s: Failed to send signal to w1 kernel thread %d.\n",
-                         __func__, dev->kpid);
+        kthread_stop(dev->thread);
 
         while (atomic_read(&dev->refcnt)) {
-                dev_dbg(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
+                dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
                                 dev->name, atomic_read(&dev->refcnt));
 
                 if (msleep_interruptible(1000))
@@ -179,7 +167,7 @@ void __w1_remove_master_device(struct w1_master *dev)
         }
 
         msg.id.mst.id = dev->id;
-        msg.id.mst.pid = dev->kpid;
+        msg.id.mst.pid = pid;
         msg.type = W1_MASTER_REMOVE;
         w1_netlink_send(dev, &msg);