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>

1 files changed, 38 insertions, 0 deletions

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 */