freezer: introduce freezer-friendly waiting macros

Introduce freezer-friendly wrappers around wait_event_interruptible() and
wait_event_interruptible_timeout(), originally defined in <linux/wait.h>, to
be used in freezable kernel threads.  Make some of the freezable kernel
threads use them.

This is necessary for the freezer to stop sending signals to kernel threads,
which is implemented in the next patch.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 45 insertions, 13 deletions

diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c
index 20896d5e5f0e..ec1b6cfefcd3 100644
--- a/drivers/input/gameport/gameport.c
+++ b/drivers/input/gameport/gameport.c
@@ -448,9 +448,8 @@ static int gameport_thread(void *nothing)
         set_freezable();
         do {
                 gameport_handle_event();
-                wait_event_interruptible(gameport_wait,
+                wait_event_freezable(gameport_wait,
                         kthread_should_stop() || !list_empty(&gameport_event_list));
-                try_to_freeze();
         } while (!kthread_should_stop());
 
         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index b3bc15acd3f5..7f5293828fbf 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -387,9 +387,8 @@ static int serio_thread(void *nothing)
         set_freezable();
         do {
                 serio_handle_event();
-                wait_event_interruptible(serio_wait,
+                wait_event_freezable(serio_wait,
                         kthread_should_stop() || !list_empty(&serio_event_list));
-                try_to_freeze();
         } while (!kthread_should_stop());
 
         printk(KERN_DEBUG "serio: kseriod exiting\n");
diff --git a/drivers/input/touchscreen/ucb1400_ts.c b/drivers/input/touchscreen/ucb1400_ts.c
index 86aed64ec0fb..89373b01d8f5 100644
--- a/drivers/input/touchscreen/ucb1400_ts.c
+++ b/drivers/input/touchscreen/ucb1400_ts.c
@@ -333,10 +333,9 @@ static int ucb1400_ts_thread(void *_ucb)
                         timeout = msecs_to_jiffies(10);
                 }
 
-                wait_event_interruptible_timeout(ucb->ts_wait,
+                wait_event_freezable_timeout(ucb->ts_wait,
                         ucb->irq_pending || ucb->ts_restart || kthread_should_stop(),
                         timeout);
-                try_to_freeze();
         }
 
         /* Send the "pen off" if we are stopping with the pen still active */
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index b203640ef1c5..445f02665577 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -527,7 +527,8 @@ static int dvb_frontend_thread(void *data)
                 up(&fepriv->sem);           /* is locked when we enter the thread... */
 restart:
                 timeout = wait_event_interruptible_timeout(fepriv->wait_queue,
-                        dvb_frontend_should_wakeup(fe) || kthread_should_stop(),
+                        dvb_frontend_should_wakeup(fe) || kthread_should_stop()
+                                || freezing(current),
                         fepriv->delay);
 
                 if (kthread_should_stop() || dvb_frontend_is_exiting(fe)) {
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 60a8f55a0cc7..036c3dea855e 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2870,10 +2870,9 @@ static int hub_thread(void *__unused)
         set_freezable();
         do {
                 hub_events();
-                wait_event_interruptible(khubd_wait,
+                wait_event_freezable(khubd_wait,
                                 !list_empty(&hub_event_list) ||
                                 kthread_should_stop());
-                try_to_freeze();
         } while (!kthread_should_stop() || !list_empty(&hub_event_list));
 
         pr_debug("%s: khubd exiting\n", usbcore_name);
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index 3451e8d03ab0..ac6114eea0c3 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -907,12 +907,9 @@ static int usb_stor_scan_thread(void * __us)
         if (delay_use > 0) {
                 printk(KERN_DEBUG "usb-storage: waiting for device "
                                 "to settle before scanning\n");
-retry:
-                wait_event_interruptible_timeout(us->delay_wait,
+                wait_event_freezable_timeout(us->delay_wait,
                                 test_bit(US_FLIDX_DISCONNECTING, &us->flags),
                                 delay_use * HZ);
-                if (try_to_freeze())
-                        goto retry;
         }
 
         /* If the device is still connected, perform the scanning */
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index efded00ad08c..08934995c7ab 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -4,6 +4,7 @@
 #define FREEZER_H_INCLUDED
 
 #include <linux/sched.h>
+#include <linux/wait.h>
 
 #ifdef CONFIG_PM_SLEEP
 /*
@@ -126,6 +127,36 @@ static inline void set_freezable(void)
         current->flags &= ~PF_NOFREEZE;
 }
 
+/*
+ * Freezer-friendly wrappers around wait_event_interruptible() and
+ * wait_event_interruptible_timeout(), originally defined in <linux/wait.h>
+ */
+
+#define wait_event_freezable(wq, condition)                             \
+({                                                                      \
+        int __retval;                                                   \
+        do {                                                            \
+                __retval = wait_event_interruptible(wq,                 \
+                                (condition) || freezing(current));      \
+                if (__retval && !freezing(current))                     \
+                        break;                                          \
+                else if (!(condition))                                  \
+                        __retval = -ERESTARTSYS;                        \
+        } while (try_to_freeze());                                      \
+        __retval;                                                       \
+})
+
+
+#define wait_event_freezable_timeout(wq, condition, timeout)            \
+({                                                                      \
+        long __retval = timeout;                                        \
+        do {                                                            \
+                __retval = wait_event_interruptible_timeout(wq,         \
+                                (condition) || freezing(current),       \
+                                __retval);                              \
+        } while (try_to_freeze());                                      \
+        __retval;                                                       \
+})
 #else /* !CONFIG_PM_SLEEP */
 static inline int frozen(struct task_struct *p) { return 0; }
 static inline int freezing(struct task_struct *p) { return 0; }
@@ -143,6 +174,13 @@ static inline void freezer_do_not_count(void) {}
 static inline void freezer_count(void) {}
 static inline int freezer_should_skip(struct task_struct *p) { return 0; }
 static inline void set_freezable(void) {}
+
+#define wait_event_freezable(wq, condition)                             \
+                wait_event_interruptible(wq, condition)
+
+#define wait_event_freezable_timeout(wq, condition, timeout)            \
+                wait_event_interruptible_timeout(wq, condition, timeout)
+
 #endif /* !CONFIG_PM_SLEEP */
 
 #endif  /* FREEZER_H_INCLUDED */