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authorArnd Bergmann <arnd@arndb.de>2010-06-01 22:53:05 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-10 13:47:43 -0700
commitbe1bc2889a4db4961ef69f47fb471ecae9f23ade (patch)
treefd6d5e46e69efd9d66e6baa184988461f608f49a /include
parent4e608671674b62e97166f903830d5553e37970e8 (diff)
tty: introduce wait_event_interruptible_tty
Calling wait_event_interruptible implicitly releases the BKL when it sleeps, but we need to do this explcitly when we have converted it to a mutex. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include')
-rw-r--r--include/linux/tty.h42
1 files changed, 42 insertions, 0 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 6ead6b60c743..955d72ea71c0 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -607,5 +607,47 @@ static inline void tty_unlock(void) __releases(kernel_lock)
}
#define tty_locked() (kernel_locked())
+/*
+ * wait_event_interruptible_tty -- wait for a condition with the tty lock held
+ *
+ * The condition we are waiting for might take a long time to
+ * become true, or might depend on another thread taking the
+ * BTM. In either case, we need to drop the BTM to guarantee
+ * forward progress. This is a leftover from the conversion
+ * from the BKL and should eventually get removed as the BTM
+ * falls out of use.
+ *
+ * Do not use in new code.
+ */
+#define wait_event_interruptible_tty(wq, condition) \
+({ \
+ int __ret = 0; \
+ if (!(condition)) { \
+ __wait_event_interruptible_tty(wq, condition, __ret); \
+ } \
+ __ret; \
+})
+
+#define __wait_event_interruptible_tty(wq, condition, ret) \
+do { \
+ DEFINE_WAIT(__wait); \
+ \
+ for (;;) { \
+ prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
+ if (condition) \
+ break; \
+ if (!signal_pending(current)) { \
+ tty_unlock(); \
+ schedule(); \
+ tty_lock(); \
+ continue; \
+ } \
+ ret = -ERESTARTSYS; \
+ break; \
+ } \
+ finish_wait(&wq, &__wait); \
+} while (0)
+
+
#endif /* __KERNEL__ */
#endif