Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 266 insertions, 0 deletions

diff --git a/include/asm-alpha/rwsem.h b/include/asm-alpha/rwsem.h
new file mode 100644
index 000000000000..8e058a67c9a4
--- /dev/null
+++ b/include/asm-alpha/rwsem.h
@@ -0,0 +1,266 @@
+#ifndef _ALPHA_RWSEM_H
+#define _ALPHA_RWSEM_H
+
+/*
+ * Written by Ivan Kokshaysky <ink@jurassic.park.msu.ru>, 2001.
+ * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
+ */
+
+#ifndef _LINUX_RWSEM_H
+#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
+#endif
+
+#ifdef __KERNEL__
+
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+
+struct rwsem_waiter;
+
+extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
+extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
+extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *);
+extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
+
+/*
+ * the semaphore definition
+ */
+struct rw_semaphore {
+        long                    count;
+#define RWSEM_UNLOCKED_VALUE            0x0000000000000000L
+#define RWSEM_ACTIVE_BIAS               0x0000000000000001L
+#define RWSEM_ACTIVE_MASK               0x00000000ffffffffL
+#define RWSEM_WAITING_BIAS              (-0x0000000100000000L)
+#define RWSEM_ACTIVE_READ_BIAS          RWSEM_ACTIVE_BIAS
+#define RWSEM_ACTIVE_WRITE_BIAS         (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
+        spinlock_t              wait_lock;
+        struct list_head        wait_list;
+#if RWSEM_DEBUG
+        int                     debug;
+#endif
+};
+
+#if RWSEM_DEBUG
+#define __RWSEM_DEBUG_INIT      , 0
+#else
+#define __RWSEM_DEBUG_INIT      /* */
+#endif
+
+#define __RWSEM_INITIALIZER(name) \
+        { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
+        LIST_HEAD_INIT((name).wait_list) __RWSEM_DEBUG_INIT }
+
+#define DECLARE_RWSEM(name) \
+        struct rw_semaphore name = __RWSEM_INITIALIZER(name)
+
+static inline void init_rwsem(struct rw_semaphore *sem)
+{
+        sem->count = RWSEM_UNLOCKED_VALUE;
+        spin_lock_init(&sem->wait_lock);
+        INIT_LIST_HEAD(&sem->wait_list);
+#if RWSEM_DEBUG
+        sem->debug = 0;
+#endif
+}
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+        long oldcount;
+#ifndef CONFIG_SMP
+        oldcount = sem->count;
+        sem->count += RWSEM_ACTIVE_READ_BIAS;
+#else
+        long temp;
+        __asm__ __volatile__(
+        "1:     ldq_l   %0,%1\n"
+        "       addq    %0,%3,%2\n"
+        "       stq_c   %2,%1\n"
+        "       beq     %2,2f\n"
+        "       mb\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
+        :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");
+#endif
+        if (unlikely(oldcount < 0))
+                rwsem_down_read_failed(sem);
+}
+
+/*
+ * trylock for reading -- returns 1 if successful, 0 if contention
+ */
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+        long old, new, res;
+
+        res = sem->count;
+        do {
+                new = res + RWSEM_ACTIVE_READ_BIAS;
+                if (new <= 0)
+                        break;
+                old = res;
+                res = cmpxchg(&sem->count, old, new);
+        } while (res != old);
+        return res >= 0 ? 1 : 0;
+}
+
+static inline void __down_write(struct rw_semaphore *sem)
+{
+        long oldcount;
+#ifndef CONFIG_SMP
+        oldcount = sem->count;
+        sem->count += RWSEM_ACTIVE_WRITE_BIAS;
+#else
+        long temp;
+        __asm__ __volatile__(
+        "1:     ldq_l   %0,%1\n"
+        "       addq    %0,%3,%2\n"
+        "       stq_c   %2,%1\n"
+        "       beq     %2,2f\n"
+        "       mb\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
+        :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
+#endif
+        if (unlikely(oldcount))
+                rwsem_down_write_failed(sem);
+}
+
+/*
+ * trylock for writing -- returns 1 if successful, 0 if contention
+ */
+static inline int __down_write_trylock(struct rw_semaphore *sem)
+{
+        long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
+                           RWSEM_ACTIVE_WRITE_BIAS);
+        if (ret == RWSEM_UNLOCKED_VALUE)
+                return 1;
+        return 0;
+}
+
+static inline void __up_read(struct rw_semaphore *sem)
+{
+        long oldcount;
+#ifndef CONFIG_SMP
+        oldcount = sem->count;
+        sem->count -= RWSEM_ACTIVE_READ_BIAS;
+#else
+        long temp;
+        __asm__ __volatile__(
+        "       mb\n"
+        "1:     ldq_l   %0,%1\n"
+        "       subq    %0,%3,%2\n"
+        "       stq_c   %2,%1\n"
+        "       beq     %2,2f\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
+        :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");
+#endif
+        if (unlikely(oldcount < 0))
+                if ((int)oldcount - RWSEM_ACTIVE_READ_BIAS == 0)
+                        rwsem_wake(sem);
+}
+
+static inline void __up_write(struct rw_semaphore *sem)
+{
+        long count;
+#ifndef CONFIG_SMP
+        sem->count -= RWSEM_ACTIVE_WRITE_BIAS;
+        count = sem->count;
+#else
+        long temp;
+        __asm__ __volatile__(
+        "       mb\n"
+        "1:     ldq_l   %0,%1\n"
+        "       subq    %0,%3,%2\n"
+        "       stq_c   %2,%1\n"
+        "       beq     %2,2f\n"
+        "       subq    %0,%3,%0\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (count), "=m" (sem->count), "=&r" (temp)
+        :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
+#endif
+        if (unlikely(count))
+                if ((int)count == 0)
+                        rwsem_wake(sem);
+}
+
+/*
+ * downgrade write lock to read lock
+ */
+static inline void __downgrade_write(struct rw_semaphore *sem)
+{
+        long oldcount;
+#ifndef CONFIG_SMP
+        oldcount = sem->count;
+        sem->count -= RWSEM_WAITING_BIAS;
+#else
+        long temp;
+        __asm__ __volatile__(
+        "1:     ldq_l   %0,%1\n"
+        "       addq    %0,%3,%2\n"
+        "       stq_c   %2,%1\n"
+        "       beq     %2,2f\n"
+        "       mb\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
+        :"Ir" (-RWSEM_WAITING_BIAS), "m" (sem->count) : "memory");
+#endif
+        if (unlikely(oldcount < 0))
+                rwsem_downgrade_wake(sem);
+}
+
+static inline void rwsem_atomic_add(long val, struct rw_semaphore *sem)
+{
+#ifndef CONFIG_SMP
+        sem->count += val;
+#else
+        long temp;
+        __asm__ __volatile__(
+        "1:     ldq_l   %0,%1\n"
+        "       addq    %0,%2,%0\n"
+        "       stq_c   %0,%1\n"
+        "       beq     %0,2f\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (temp), "=m" (sem->count)
+        :"Ir" (val), "m" (sem->count));
+#endif
+}
+
+static inline long rwsem_atomic_update(long val, struct rw_semaphore *sem)
+{
+#ifndef CONFIG_SMP
+        sem->count += val;
+        return sem->count;
+#else
+        long ret, temp;
+        __asm__ __volatile__(
+        "1:     ldq_l   %0,%1\n"
+        "       addq    %0,%3,%2\n"
+        "       addq    %0,%3,%0\n"
+        "       stq_c   %2,%1\n"
+        "       beq     %2,2f\n"
+        ".subsection 2\n"
+        "2:     br      1b\n"
+        ".previous"
+        :"=&r" (ret), "=m" (sem->count), "=&r" (temp)
+        :"Ir" (val), "m" (sem->count));
+
+        return ret;
+#endif
+}
+
+#endif /* __KERNEL__ */
+#endif /* _ALPHA_RWSEM_H */