Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[sfrench/cifs-2.6.git] / include / linux / sched.h

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4d568288abf9f66c85cf96297f076b94af962a07..26f499810dfaacf754fde496bb5b03a04c30903d 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1904,12 +1904,24 @@ static inline int _cond_resched(void) { return 0; }
 })
 
 extern int __cond_resched_lock(spinlock_t *lock);
+extern int __cond_resched_rwlock_read(rwlock_t *lock);
+extern int __cond_resched_rwlock_write(rwlock_t *lock);
 
 #define cond_resched_lock(lock) ({                             \
        ___might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);\
        __cond_resched_lock(lock);                              \
 })
 
+#define cond_resched_rwlock_read(lock) ({                      \
+       __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \
+       __cond_resched_rwlock_read(lock);                       \
+})
+
+#define cond_resched_rwlock_write(lock) ({                     \
+       __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \
+       __cond_resched_rwlock_write(lock);                      \
+})
+
 static inline void cond_resched_rcu(void)
 {
 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
@@ -1933,6 +1945,23 @@ static inline int spin_needbreak(spinlock_t *lock)
 #endif
 }
 
+/*
+ * Check if a rwlock is contended.
+ * Returns non-zero if there is another task waiting on the rwlock.
+ * Returns zero if the lock is not contended or the system / underlying
+ * rwlock implementation does not support contention detection.
+ * Technically does not depend on CONFIG_PREEMPTION, but a general need
+ * for low latency.
+ */
+static inline int rwlock_needbreak(rwlock_t *lock)
+{
+#ifdef CONFIG_PREEMPTION
+       return rwlock_is_contended(lock);
+#else
+       return 0;
+#endif
+}
+
 static __always_inline bool need_resched(void)
 {
        return unlikely(tif_need_resched());