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>

2 files changed, 23 insertions, 22 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index aac03f151fe..730faa49d8d 100644
--- 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 ed3228017da..36ff40250b6 100644
--- 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);