patch-2.1.36 linux/include/asm-alpha/spinlock.h

• Lines: 52
• Date: Tue Apr 22 22:38:40 1997
• Orig file: v2.1.35/linux/include/asm-alpha/spinlock.h
• Orig date: Wed Apr 16 14:15:00 1997

diff -u --recursive --new-file v2.1.35/linux/include/asm-alpha/spinlock.h linux/include/asm-alpha/spinlock.h
@@ -9,6 +9,7 @@
 #define spin_lock_init(lock)			do { } while(0)
 #define spin_lock(lock)				do { } while(0)
 #define spin_trylock(lock)			do { } while(0)
+#define spin_unlock_wait(lock)			do { } while(0)
 #define spin_unlock(lock)			do { } while(0)
 #define spin_lock_irq(lock)			setipl(7)
 #define spin_unlock_irq(lock)			setipl(0)
@@ -16,6 +17,33 @@
 #define spin_lock_irqsave(lock, flags)		swpipl(flags,7)
 #define spin_unlock_irqrestore(lock, flags)	setipl(flags)
 
+/*
+ * Read-write spinlocks, allowing multiple readers
+ * but only one writer.
+ *
+ * NOTE! it is quite common to have readers in interrupts
+ * but no interrupt writers. For those circumstances we
+ * can "mix" irq-safe locks - any writer needs to get a
+ * irq-safe write-lock, but readers can get non-irqsafe
+ * read-locks.
+ */
+typedef struct { } rwlock_t;
+#define RW_LOCK_UNLOCKED { }
+
+#define read_lock(lock)		do { } while(0)
+#define read_unlock(lock)	do { } while(0)
+#define write_lock(lock)	do { } while(0)
+#define write_unlock(lock)	do { } while(0)
+#define read_lock_irq(lock)	cli()
+#define read_unlock_irq(lock)	sti()
+#define write_lock_irq(lock)	cli()
+#define write_unlock_irq(lock)	sti()
+
+#define read_lock_irqsave(lock, flags)		save_and_cli(flags)
+#define read_unlock_irqrestore(lock, flags)	restore_flags(flags)
+#define write_lock_irqsave(lock, flags)		save_and_cli(flags)
+#define write_unlock_irqrestore(lock, flags)	restore_flags(flags)
+
 #else
 
 /* Simple spin lock operations.  There are two variants, one clears IRQ's
@@ -30,6 +58,9 @@
 } spinlock_t;
 
 #define SPIN_LOCK_UNLOCKED { 0, 0 }
+
+#define spin_lock_init(lock)	do { (lock)->lock = 0; (lock)->previous = 0; } while(0)
+#define spin_unlock_wait(lock)	do { barrier(); } while(((volatile spinlock_t *)lock)->lock)
 
 typedef struct { unsigned long a[100]; } __dummy_lock_t;
 #define __dummy_lock(lock) (*(__dummy_lock_t *)(lock))