Implement a proper rw_tryupgrade

[mirror_spl.git] / include / linux / rwsem_compat.h

diff --git a/include/linux/rwsem_compat.h b/include/linux/rwsem_compat.h
index 5841d7c286978011df049ecbc2520edb249bdf7a..9a4df26738c8bac289040126e5fa6af20dac8552 100644 (file)
--- a/include/linux/rwsem_compat.h
+++ b/include/linux/rwsem_compat.h
@@ -27,6 +27,23 @@
 
 #include <linux/rwsem.h>
 
+#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
+#define        SPL_RWSEM_SINGLE_READER_VALUE   (1)
+#define        SPL_RWSEM_SINGLE_WRITER_VALUE   (-1)
+#else
+#define        SPL_RWSEM_SINGLE_READER_VALUE   (RWSEM_ACTIVE_READ_BIAS)
+#define        SPL_RWSEM_SINGLE_WRITER_VALUE   (RWSEM_ACTIVE_WRITE_BIAS)
+#endif
+
+/* Linux 3.16 change activity to count for rwsem-spinlock */
+#ifdef HAVE_RWSEM_ACTIVITY
+#define        RWSEM_COUNT(sem)        sem->activity
+#else
+#define        RWSEM_COUNT(sem)        sem->count
+#endif
+
+int rwsem_tryupgrade(struct rw_semaphore *rwsem);
+
 #if defined(RWSEM_SPINLOCK_IS_RAW)
 #define spl_rwsem_lock_irqsave(lk, fl)       raw_spin_lock_irqsave(lk, fl)
 #define spl_rwsem_unlock_irqrestore(lk, fl)  raw_spin_unlock_irqrestore(lk, fl)