[PATCH] EDAC: switch to kthread_ API

This patch was originally posted by Christoph Hellwig (see
http://lkml.org/lkml/2006/2/14/331):

"Christoph Hellwig" <hch@lst.de> wrote:
> Use the kthread_ API instead of opencoding lots of hairy code for kernel
> thread creation and teardown, including tasklist_lock abuse.
>

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Cc: <dave_peterson@pobox.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 9c20527..8a7a3ab 100644 (file)
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -29,6 +29,7 @@
 #include <linux/list.h>
 #include <linux/sysdev.h>
 #include <linux/ctype.h>
+#include <linux/kthread.h>
 
 #include <asm/uaccess.h>
 #include <asm/page.h>
@@ -64,6 +65,8 @@ static atomic_t pci_parity_count = ATOMIC_INIT(0);
 static DECLARE_MUTEX(mem_ctls_mutex);
 static struct list_head mc_devices = LIST_HEAD_INIT(mc_devices);
 
+static struct task_struct *edac_thread;
+
 /* Structure of the whitelist and blacklist arrays */
 struct edac_pci_device_list {
        unsigned int  vendor;           /* Vendor ID */
@@ -2073,7 +2076,6 @@ static inline void check_mc_devices (void)
  */
 static void do_edac_check(void)
 {
-
        debugf3("MC: " __FILE__ ": %s()\n", __func__);
 
        check_mc_devices();
@@ -2081,62 +2083,16 @@ static void do_edac_check(void)
        do_pci_parity_check();
 }
 
-
-/*
- * EDAC thread state information
- */
-struct bs_thread_info
-{
-       struct task_struct *task;
-       struct completion *event;
-       char *name;
-       void (*run)(void);
-};
-
-static struct bs_thread_info bs_thread;
-
-/*
- *  edac_kernel_thread
- *      This the kernel thread that processes edac operations
- *      in a normal thread environment
- */
 static int edac_kernel_thread(void *arg)
 {
-       struct bs_thread_info *thread = (struct bs_thread_info *) arg;
-
-       /* detach thread */
-       daemonize(thread->name);
-
-       current->exit_signal = SIGCHLD;
-       allow_signal(SIGKILL);
-       thread->task = current;
-
-       /* indicate to starting task we have started */
-       complete(thread->event);
-
-       /* loop forever, until we are told to stop */
-       while(thread->run != NULL) {
-               void (*run)(void);
-
-               /* call the function to check the memory controllers */
-               run = thread->run;
-               if (run)
-                       run();
-
-               if (signal_pending(current))
-                       flush_signals(current);
-
-               /* ensure we are interruptable */
-               set_current_state(TASK_INTERRUPTIBLE);
+       while (!kthread_should_stop()) {
+               do_edac_check();
 
                /* goto sleep for the interval */
-               schedule_timeout((HZ * poll_msec) / 1000);
+               schedule_timeout_interruptible((HZ * poll_msec) / 1000);
                try_to_freeze();
        }
 
-       /* notify waiter that we are exiting */
-       complete(thread->event);
-
        return 0;
 }
 
@@ -2146,9 +2102,6 @@ static int edac_kernel_thread(void *arg)
  */
 static int __init edac_mc_init(void)
 {
-       int ret;
-       struct completion event;
-
        printk(KERN_INFO "MC: " __FILE__ " version " EDAC_MC_VERSION "\n");
 
        /*
@@ -2176,24 +2129,15 @@ static int __init edac_mc_init(void)
                return -ENODEV;
        }
 
-       /* Create our kernel thread */
-       init_completion(&event);
-       bs_thread.event = &event;
-       bs_thread.name = "kedac";
-       bs_thread.run = do_edac_check;
-
        /* create our kernel thread */
-       ret = kernel_thread(edac_kernel_thread, &bs_thread, CLONE_KERNEL);
-       if (ret < 0) {
+       edac_thread = kthread_run(edac_kernel_thread, NULL, "kedac");
+       if (IS_ERR(edac_thread)) {
                /* remove the sysfs entries */
                edac_sysfs_memctrl_teardown();
                edac_sysfs_pci_teardown();
-               return -ENOMEM;
+               return PTR_ERR(edac_thread);
        }
 
-       /* wait for our kernel theard ack that it is up and running */
-       wait_for_completion(&event);
-
        return 0;
 }
 
@@ -2204,21 +2148,9 @@ static int __init edac_mc_init(void)
  */
 static void __exit edac_mc_exit(void)
 {
-       struct completion event;
-
        debugf0("MC: " __FILE__ ": %s()\n", __func__);
 
-       init_completion(&event);
-       bs_thread.event = &event;
-
-       /* As soon as ->run is set to NULL, the task could disappear,
-        * so we need to hold tasklist_lock until we have sent the signal
-        */
-       read_lock(&tasklist_lock);
-       bs_thread.run = NULL;
-       send_sig(SIGKILL, bs_thread.task, 1);
-       read_unlock(&tasklist_lock);
-       wait_for_completion(&event);
+       kthread_stop(edac_thread);
 
         /* tear down the sysfs device */
        edac_sysfs_memctrl_teardown();