On Fri, May 04, 2001 at 10:22:53AM +0100, David Howells wrote:
> I don't know whether it will (a) compile, or (b) work... I don't have an alpha
> to play with.

Neither (a) nor (b) ;-)  Corrected asm-alpha/rwsem.h attached.
Also small fix for lib/rwsem.c -- RWSEM_WAITING_BIAS-RWSEM_ACTIVE_BIAS
won't fit in the __s32 if counters are 64-bit.

--- linux/lib/rwsem.c.orig      Sat Apr 28 00:58:28 2001
+++ linux/lib/rwsem.c   Fri May  4 17:38:06 2001
@@ -112,7 +112,7 @@ static inline struct rw_semaphore *__rws
  */
 static inline struct rw_semaphore *rwsem_down_failed_common(struct rw_semaphore *sem,
                                                                 struct rwsem_waiter 
*waiter,
-                                                                __s32 adjustment)
+                                                                signed long 
+adjustment)
 {
        struct task_struct *tsk = current;
        signed long count;

Ivan.

#ifndef _ALPHA_RWSEM_H
#define _ALPHA_RWSEM_H

/*
 * Written by Ivan Kokshaysky <[EMAIL PROTECTED]>, 2001.
 * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
 */

#ifndef _LINUX_RWSEM_H
#error please dont include asm/rwsem.h directly, use linux/rwsem.h instead
#endif

#ifdef __KERNEL__

#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 *);

/*
 * 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, temp;
        __asm__ __volatile__(
        "1:     ldq_l   %0,%1\n"
        "       addq    %0,%3,%2\n"
        "       stq_c   %2,%1\n"
        "       beq     %2,2f\n"
#ifdef CONFIG_SMP
        "       mb\n"
#endif
        ".subsection 2\n"
        "2:     br      1b\n"
        ".previous"
        :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
        :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");

        if (oldcount < 0)
                rwsem_down_read_failed(sem);
}

static inline void __down_write(struct rw_semaphore *sem)
{
        long granted, temp;
        __asm__ __volatile__(
        "1:     ldq_l   %0,%1\n"
        "       addq    %0,%3,%2\n"
        "       stq_c   %2,%1\n"
        "       beq     %2,2f\n"
#ifdef CONFIG_SMP
        "       mb\n"
#endif
        "       cmpeq   %0,0,%0\n"
        ".subsection 2\n"
        "2:     br      1b\n"
        ".previous"
        :"=&r" (granted), "=m" (sem->count), "=&r" (temp)
        :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");

        if (!granted)
                rwsem_down_write_failed(sem);
}

static inline void __up_read(struct rw_semaphore *sem)
{
        long oldcount, temp;
        __asm__ __volatile__(
#ifdef CONFIG_SMP
        "       mb\n"
#endif
        "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");

        if (oldcount < 0)
                if ((oldcount & RWSEM_ACTIVE_MASK) == 0)
                        rwsem_wake(sem);
}

static inline void __up_write(struct rw_semaphore *sem)
{
        long count, cmp;
        __asm__ __volatile__(
#ifdef CONFIG_SMP
        "       mb\n"
#endif
        "1:     ldq_l   %0,%1\n"
        "       subq    %0,%3,%2\n"
        "       stq_c   %2,%1\n"
        "       beq     %2,2f\n"
        "       cmpeq   %0,%3,%2\n"
        ".subsection 2\n"
        "2:     br      1b\n"
        ".previous"
        :"=&r" (count), "=m" (sem->count), "=&r" (cmp)
        :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");

        if (!cmp)
                if ((int)count - RWSEM_ACTIVE_BIAS == 0)
                        rwsem_wake(sem);
}

static inline void rwsem_atomic_add(long val, struct rw_semaphore *sem)
{
        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));
}

static inline long rwsem_atomic_update(long val, struct rw_semaphore *sem)
{
        long temp, ret;
        __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 /* __KERNEL__ */
#endif /* _ALPHA_RWSEM_H */

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