W1: don't delay search start

Move the creation of the w1_process thread to after the device has been
initialized.  This way w1_process doesn't have to check to see if it has
been initialized and the bus search can proceed without sleeping.  That
also eliminates two checks in the w1_process loop.  The sleep now happens
at the end of the loop not the beginning.

Also added a comment for why the atomic_set was 2.

Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index aac03f1..730faa4 100644 (file)
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -813,21 +813,14 @@ int w1_process(void *data)
        struct w1_master *dev = (struct w1_master *) data;
 
        while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
+               if (dev->search_count) {
+                       mutex_lock(&dev->mutex);
+                       w1_search_process(dev, W1_SEARCH);
+                       mutex_unlock(&dev->mutex);
+               }
+
                try_to_freeze();
                msleep_interruptible(w1_timeout * 1000);
-
-               if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
-                       break;
-
-               if (!dev->initialized)
-                       continue;
-
-               if (dev->search_count == 0)
-                       continue;
-
-               mutex_lock(&dev->mutex);
-               w1_search_process(dev, W1_SEARCH);
-               mutex_unlock(&dev->mutex);
        }
 
        atomic_dec(&dev->refcnt);

diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index ed32280..36ff402 100644 (file)
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -61,6 +61,9 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
        dev->slave_ttl          = slave_ttl;
         dev->search_count      = -1; /* continual scan */
 
+       /* 1 for w1_process to decrement
+        * 1 for __w1_remove_master_device to decrement
+        */
        atomic_set(&dev->refcnt, 2);
 
        INIT_LIST_HEAD(&dev->slist);
@@ -109,23 +112,23 @@ int w1_add_master_device(struct w1_bus_master *master)
        if (!dev)
                return -ENOMEM;
 
+       retval =  w1_create_master_attributes(dev);
+       if (retval)
+               goto err_out_free_dev;
+
+       memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
+
+       dev->initialized = 1;
+
        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",
                         retval);
-               goto err_out_free_dev;
+               goto err_out_rm_attr;
        }
 
-       retval =  w1_create_master_attributes(dev);
-       if (retval)
-               goto err_out_kill_thread;
-
-       memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
-
-       dev->initialized = 1;
-
        mutex_lock(&w1_mlock);
        list_add(&dev->w1_master_entry, &w1_masters);
        mutex_unlock(&w1_mlock);
@@ -137,8 +140,13 @@ int w1_add_master_device(struct w1_bus_master *master)
 
        return 0;
 
+#if 0 /* Thread cleanup code, not required currently. */
 err_out_kill_thread:
+       set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
        kthread_stop(dev->thread);
+#endif
+err_out_rm_attr:
+       w1_destroy_master_attributes(dev);
 err_out_free_dev:
        w1_free_dev(dev);