[PATCH] md: use kthread infrastructure in md

Switch MD to use the kthread infrastructure, to simplify the code and get rid
of tasklist_lock abuse in md_unregister_thread.

Also don't flush signals in md_thread, as the called thread will always do
that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 38 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 008149e2bc4a..30e3624f3d90 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -34,6 +34,7 @@
 
 #include <linux/module.h>
 #include <linux/config.h>
+#include <linux/kthread.h>
 #include <linux/linkage.h>
 #include <linux/raid/md.h>
 #include <linux/raid/bitmap.h>
@@ -3049,18 +3050,6 @@ static int md_thread(void * arg)
 {
         mdk_thread_t *thread = arg;
 
-        lock_kernel();
-
-        /*
-         * Detach thread
-         */
-
-        daemonize(thread->name, mdname(thread->mddev));
-
-        current->exit_signal = SIGCHLD;
-        allow_signal(SIGKILL);
-        thread->tsk = current;
-
         /*
          * md_thread is a 'system-thread', it's priority should be very
          * high. We avoid resource deadlocks individually in each
@@ -3072,14 +3061,14 @@ static int md_thread(void * arg)
          * bdflush, otherwise bdflush will deadlock if there are too
          * many dirty RAID5 blocks.
          */
-        unlock_kernel();
 
         complete(thread->event);
-        while (thread->run) {
+        while (!kthread_should_stop()) {
                 void (*run)(mddev_t *);
 
                 wait_event_interruptible_timeout(thread->wqueue,
-                                                 test_bit(THREAD_WAKEUP, &thread->flags),
+                                                 test_bit(THREAD_WAKEUP, &thread->flags)
+                                                 || kthread_should_stop(),
                                                  thread->timeout);
                 try_to_freeze();
 
@@ -3088,11 +3077,8 @@ static int md_thread(void * arg)
                 run = thread->run;
                 if (run)
                         run(thread->mddev);
-
-                if (signal_pending(current))
-                        flush_signals(current);
         }
-        complete(thread->event);
+
         return 0;
 }
 
@@ -3109,11 +3095,9 @@ mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
                                  const char *name)
 {
         mdk_thread_t *thread;
-        int ret;
         struct completion event;
 
-        thread = (mdk_thread_t *) kmalloc
-                                (sizeof(mdk_thread_t), GFP_KERNEL);
+        thread = kmalloc(sizeof(mdk_thread_t), GFP_KERNEL);
         if (!thread)
                 return NULL;
 
@@ -3126,8 +3110,8 @@ mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
         thread->mddev = mddev;
         thread->name = name;
         thread->timeout = MAX_SCHEDULE_TIMEOUT;
-        ret = kernel_thread(md_thread, thread, 0);
-        if (ret < 0) {
+        thread->tsk = kthread_run(md_thread, thread, mdname(thread->mddev));
+        if (IS_ERR(thread->tsk)) {
                 kfree(thread);
                 return NULL;
         }
@@ -3137,21 +3121,9 @@ mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
 
 void md_unregister_thread(mdk_thread_t *thread)
 {
-        struct completion event;
-
-        init_completion(&event);
-
-        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
-         */
         dprintk("interrupting MD-thread pid %d\n", thread->tsk->pid);
-        read_lock(&tasklist_lock);
-        thread->run = NULL;
-        send_sig(SIGKILL, thread->tsk, 1);
-        read_unlock(&tasklist_lock);
-        wait_for_completion(&event);
+
+        kthread_stop(thread->tsk);
         kfree(thread);
 }