USB: usbatm: convert heavy init dances to kthread API

This is an attempt to kill two birds with one stone.

First, we kill one more user of kernel_thread, which is scheduled
for removal. Second - we kill one of the last users of kill_proc -
the function which is also to be removed, because it uses a pid_t
which is not safe now.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 16 insertions, 13 deletions

diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c
index e717f5b1caee..07228721cafe 100644
--- a/drivers/usb/atm/usbatm.c
+++ b/drivers/usb/atm/usbatm.c
@@ -80,6 +80,7 @@
 #include <linux/stat.h>
 #include <linux/timer.h>
 #include <linux/wait.h>
+#include <linux/kthread.h>
 
 #ifdef VERBOSE_DEBUG
 static int usbatm_print_packet(const unsigned char *data, int len);
@@ -1014,10 +1015,7 @@ static int usbatm_do_heavy_init(void *arg)
         struct usbatm_data *instance = arg;
         int ret;
 
-        daemonize(instance->driver->driver_name);
         allow_signal(SIGTERM);
-        instance->thread_pid = current->pid;
-
         complete(&instance->thread_started);
 
         ret = instance->driver->heavy_init(instance, instance->usb_intf);
@@ -1026,7 +1024,7 @@ static int usbatm_do_heavy_init(void *arg)
                 ret = usbatm_atm_init(instance);
 
         mutex_lock(&instance->serialize);
-        instance->thread_pid = -1;
+        instance->thread = NULL;
         mutex_unlock(&instance->serialize);
 
         complete_and_exit(&instance->thread_exited, ret);
@@ -1034,13 +1032,18 @@ static int usbatm_do_heavy_init(void *arg)
 
 static int usbatm_heavy_init(struct usbatm_data *instance)
 {
-        int ret = kernel_thread(usbatm_do_heavy_init, instance, CLONE_FS | CLONE_FILES);
-
-        if (ret < 0) {
-                usb_err(instance, "%s: failed to create kernel_thread (%d)!\n", __func__, ret);
-                return ret;
+        struct task_struct *t;
+
+        t = kthread_create(usbatm_do_heavy_init, instance,
+                        instance->driver->driver_name);
+        if (IS_ERR(t)) {
+                usb_err(instance, "%s: failed to create kernel_thread (%ld)!\n",
+                                __func__, PTR_ERR(t));
+                return PTR_ERR(t);
         }
 
+        instance->thread = t;
+        wake_up_process(t);
         wait_for_completion(&instance->thread_started);
 
         return 0;
@@ -1124,7 +1127,7 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
         kref_init(&instance->refcount);         /* dropped in usbatm_usb_disconnect */
         mutex_init(&instance->serialize);
 
-        instance->thread_pid = -1;
+        instance->thread = NULL;
         init_completion(&instance->thread_started);
         init_completion(&instance->thread_exited);
 
@@ -1287,8 +1290,8 @@ void usbatm_usb_disconnect(struct usb_interface *intf)
 
         mutex_lock(&instance->serialize);
         instance->disconnected = 1;
-        if (instance->thread_pid >= 0)
-                kill_proc(instance->thread_pid, SIGTERM, 1);
+        if (instance->thread != NULL)
+                send_sig(SIGTERM, instance->thread, 1);
         mutex_unlock(&instance->serialize);
 
         wait_for_completion(&instance->thread_exited);
diff --git a/drivers/usb/atm/usbatm.h b/drivers/usb/atm/usbatm.h
index fc6c2be5999c..e6887c6cf3cf 100644
--- a/drivers/usb/atm/usbatm.h
+++ b/drivers/usb/atm/usbatm.h
@@ -175,7 +175,7 @@ struct usbatm_data {
         int disconnected;
 
         /* heavy init */
-        int thread_pid;
+        struct task_struct *thread;
         struct completion thread_started;
         struct completion thread_exited;