W1: w1_process, block or sleep

The w1_process thread's sleeping and termination has been modified.
msleep_interruptible was replaced by schedule_timeout and schedule to
allow for kthread_stop and wake_up_process to interrupt the sleep and the
unbounded sleeping when a bus search is disabled.  The W1_MASTER_NEED_EXIT
and flags variable were removed as they were redundant with
kthread_should_stop and kthread_stop.  If w1_process is sleeping,
requesting a search will immediately wake it up rather than waiting for
the end of msleep_interruptible previously.

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>

1 files changed, 17 insertions, 3 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 730faa49d8dc..9b5c11701c37 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -251,6 +251,7 @@ static ssize_t w1_master_attribute_store_search(struct device * dev,
         mutex_lock(&md->mutex);
         md->search_count = simple_strtol(buf, NULL, 0);
         mutex_unlock(&md->mutex);
+        wake_up_process(md->thread);
 
         return count;
 }
@@ -773,7 +774,7 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb
                         tmp64 = (triplet_ret >> 2);
                         rn |= (tmp64 << i);
 
-                        if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
+                        if (kthread_should_stop()) {
                                 printk(KERN_INFO "Abort w1_search (exiting)\n");
                                 return;
                         }
@@ -811,8 +812,12 @@ void w1_search_process(struct w1_master *dev, u8 search_type)
 int w1_process(void *data)
 {
         struct w1_master *dev = (struct w1_master *) data;
+        /* As long as w1_timeout is only set by a module parameter the sleep
+         * time can be calculated in jiffies once.
+         */
+        const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
 
-        while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
+        while (!kthread_should_stop()) {
                 if (dev->search_count) {
                         mutex_lock(&dev->mutex);
                         w1_search_process(dev, W1_SEARCH);
@@ -820,7 +825,16 @@ int w1_process(void *data)
                 }
 
                 try_to_freeze();
-                msleep_interruptible(w1_timeout * 1000);
+                __set_current_state(TASK_INTERRUPTIBLE);
+
+                if (kthread_should_stop())
+                        break;
+
+                /* Only sleep when the search is active. */
+                if (dev->search_count)
+                        schedule_timeout(jtime);
+                else
+                        schedule();
         }
 
         atomic_dec(&dev->refcnt);