diff -urN 2.4.5pre3/arch/alpha/config.in rwsem/arch/alpha/config.in
--- 2.4.5pre3/arch/alpha/config.in Tue May 1 19:35:17 2001
+++ rwsem/arch/alpha/config.in Wed May 16 23:26:06 2001
@@ -6,7 +6,6 @@
define_bool CONFIG_ALPHA y
define_bool CONFIG_UID16 n
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_name "Kernel configuration of Linux for Alpha machines"
diff -urN 2.4.5pre3/arch/alpha/kernel/alpha_ksyms.c rwsem/arch/alpha/kernel/alpha_ksyms.c
--- 2.4.5pre3/arch/alpha/kernel/alpha_ksyms.c Tue May 1 19:35:17 2001
+++ rwsem/arch/alpha/kernel/alpha_ksyms.c Wed May 16 23:26:06 2001
@@ -173,10 +173,6 @@
EXPORT_SYMBOL(down_interruptible);
EXPORT_SYMBOL(down_trylock);
EXPORT_SYMBOL(up);
-EXPORT_SYMBOL(down_read);
-EXPORT_SYMBOL(down_write);
-EXPORT_SYMBOL(up_read);
-EXPORT_SYMBOL(up_write);
/*
* SMP-specific symbols.
diff -urN 2.4.5pre3/arch/arm/config.in rwsem/arch/arm/config.in
--- 2.4.5pre3/arch/arm/config.in Tue May 1 19:35:17 2001
+++ rwsem/arch/arm/config.in Wed May 16 23:26:06 2001
@@ -10,8 +10,6 @@
define_bool CONFIG_MCA n
define_bool CONFIG_UID16 y
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
-
mainmenu_option next_comment
comment 'Code maturity level options'
diff -urN 2.4.5pre3/arch/cris/config.in rwsem/arch/cris/config.in
--- 2.4.5pre3/arch/cris/config.in Wed May 16 22:02:37 2001
+++ rwsem/arch/cris/config.in Wed May 16 23:26:06 2001
@@ -6,7 +6,6 @@
define_bool CONFIG_UID16 y
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_option next_comment
comment 'Code maturity level options'
diff -urN 2.4.5pre3/arch/i386/config.in rwsem/arch/i386/config.in
--- 2.4.5pre3/arch/i386/config.in Wed May 16 22:02:37 2001
+++ rwsem/arch/i386/config.in Wed May 16 23:26:06 2001
@@ -51,7 +51,6 @@
define_bool CONFIG_X86_XADD n
define_int CONFIG_X86_L1_CACHE_SHIFT 4
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
- define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
else
define_bool CONFIG_X86_WP_WORKS_OK y
define_bool CONFIG_X86_INVLPG y
@@ -59,8 +58,7 @@
define_bool CONFIG_X86_XADD y
define_bool CONFIG_X86_BSWAP y
define_bool CONFIG_X86_POPAD_OK y
- define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
- define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
+ define_bool CONFIG_RWSEM_XCHGADD y
fi
if [ "$CONFIG_M486" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 4
diff -urN 2.4.5pre3/arch/ia64/config.in rwsem/arch/ia64/config.in
--- 2.4.5pre3/arch/ia64/config.in Tue May 1 19:35:18 2001
+++ rwsem/arch/ia64/config.in Wed May 16 23:26:06 2001
@@ -24,7 +24,6 @@
define_bool CONFIG_MCA n
define_bool CONFIG_SBUS n
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
choice 'IA-64 processor type' \
"Itanium CONFIG_ITANIUM \
diff -urN 2.4.5pre3/arch/m68k/config.in rwsem/arch/m68k/config.in
--- 2.4.5pre3/arch/m68k/config.in Tue May 1 19:35:19 2001
+++ rwsem/arch/m68k/config.in Wed May 16 23:26:06 2001
@@ -5,7 +5,6 @@
define_bool CONFIG_UID16 y
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_name "Linux/68k Kernel Configuration"
diff -urN 2.4.5pre3/arch/mips/config.in rwsem/arch/mips/config.in
--- 2.4.5pre3/arch/mips/config.in Tue May 1 19:35:19 2001
+++ rwsem/arch/mips/config.in Wed May 16 23:26:06 2001
@@ -29,7 +29,6 @@
bool 'Support for SNI RM200 PCI' CONFIG_SNI_RM200_PCI
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
#
# Select some configuration options automatically for certain systems.
diff -urN 2.4.5pre3/arch/mips64/config.in rwsem/arch/mips64/config.in
--- 2.4.5pre3/arch/mips64/config.in Tue May 1 19:35:20 2001
+++ rwsem/arch/mips64/config.in Wed May 16 23:26:06 2001
@@ -26,7 +26,6 @@
endmenu
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
#
# Select some configuration options automatically based on user selections
diff -urN 2.4.5pre3/arch/parisc/config.in rwsem/arch/parisc/config.in
--- 2.4.5pre3/arch/parisc/config.in Tue May 1 19:35:20 2001
+++ rwsem/arch/parisc/config.in Wed May 16 23:26:06 2001
@@ -8,7 +8,6 @@
define_bool CONFIG_PARISC y
define_bool CONFIG_UID16 n
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_option next_comment
comment 'Code maturity level options'
diff -urN 2.4.5pre3/arch/ppc/config.in rwsem/arch/ppc/config.in
--- 2.4.5pre3/arch/ppc/config.in Wed May 16 22:02:38 2001
+++ rwsem/arch/ppc/config.in Wed May 16 23:27:35 2001
@@ -3,8 +3,7 @@
# see Documentation/kbuild/config-language.txt.
#
define_bool CONFIG_UID16 n
-define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
+define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
mainmenu_name "Linux/PowerPC Kernel Configuration"
diff -urN 2.4.5pre3/arch/s390/config.in rwsem/arch/s390/config.in
--- 2.4.5pre3/arch/s390/config.in Tue May 1 19:35:20 2001
+++ rwsem/arch/s390/config.in Wed May 16 23:26:06 2001
@@ -8,7 +8,6 @@
define_bool CONFIG_MCA n
define_bool CONFIG_UID16 y
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_name "Linux Kernel Configuration"
define_bool CONFIG_ARCH_S390 y
diff -urN 2.4.5pre3/arch/s390x/config.in rwsem/arch/s390x/config.in
--- 2.4.5pre3/arch/s390x/config.in Tue May 1 19:35:20 2001
+++ rwsem/arch/s390x/config.in Wed May 16 23:26:06 2001
@@ -7,7 +7,6 @@
define_bool CONFIG_EISA n
define_bool CONFIG_MCA n
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_name "Linux Kernel Configuration"
define_bool CONFIG_ARCH_S390 y
diff -urN 2.4.5pre3/arch/sh/config.in rwsem/arch/sh/config.in
--- 2.4.5pre3/arch/sh/config.in Tue May 1 19:35:20 2001
+++ rwsem/arch/sh/config.in Wed May 16 23:26:06 2001
@@ -8,7 +8,6 @@
define_bool CONFIG_UID16 y
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
mainmenu_option next_comment
comment 'Code maturity level options'
diff -urN 2.4.5pre3/arch/sparc/config.in rwsem/arch/sparc/config.in
--- 2.4.5pre3/arch/sparc/config.in Tue May 1 19:35:21 2001
+++ rwsem/arch/sparc/config.in Wed May 16 23:26:06 2001
@@ -49,7 +49,6 @@
define_bool CONFIG_SUN_AUXIO y
define_bool CONFIG_SUN_IO y
define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM n
bool 'Support for SUN4 machines (disables SUN4[CDM] support)' CONFIG_SUN4
if [ "$CONFIG_SUN4" != "y" ]; then
diff -urN 2.4.5pre3/arch/sparc64/config.in rwsem/arch/sparc64/config.in
--- 2.4.5pre3/arch/sparc64/config.in Wed May 16 22:02:41 2001
+++ rwsem/arch/sparc64/config.in Wed May 16 23:26:06 2001
@@ -33,8 +33,8 @@
# Global things across all Sun machines.
define_bool CONFIG_HAVE_DEC_LOCK y
-define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
-define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
+# sorry I broke it again
+define_bool CONFIG_RWSEM_GENERIC_SPINLOCK y
define_bool CONFIG_ISA n
define_bool CONFIG_EISA n
define_bool CONFIG_MCA n
diff -urN 2.4.5pre3/include/asm-alpha/rwsem_xchgadd.h rwsem/include/asm-alpha/rwsem_xchgadd.h
--- 2.4.5pre3/include/asm-alpha/rwsem_xchgadd.h Thu Jan 1 01:00:00 1970
+++ rwsem/include/asm-alpha/rwsem_xchgadd.h Wed May 16 23:26:06 2001
@@ -0,0 +1,27 @@
+#ifndef _ALPHA_RWSEM_XCHGADD_H
+#define _ALPHA_RWSEM_XCHGADD_H
+
+/* WRITEME */
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+}
+
+static inline void __down_write(struct rw_semaphore *sem)
+{
+}
+
+static inline void __up_read(struct rw_semaphore *sem)
+{
+}
+
+static inline void __up_write(struct rw_semaphore *sem)
+{
+}
+
+static inline long rwsem_xchgadd(long value, long * count)
+{
+ return value;
+}
+
+#endif
diff -urN 2.4.5pre3/include/asm-i386/rwsem.h rwsem/include/asm-i386/rwsem.h
--- 2.4.5pre3/include/asm-i386/rwsem.h Tue May 8 01:05:16 2001
+++ rwsem/include/asm-i386/rwsem.h Thu Jan 1 01:00:00 1970
@@ -1,226 +0,0 @@
-/* rwsem.h: R/W semaphores implemented using XADD/CMPXCHG for i486+
- *
- * Written by David Howells (dhowells@redhat.com).
- *
- * Derived from asm-i386/semaphore.h
- *
- *
- * The MSW of the count is the negated number of active writers and waiting
- * lockers, and the LSW is the total number of active locks
- *
- * The lock count is initialized to 0 (no active and no waiting lockers).
- *
- * When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an
- * uncontended lock. This can be determined because XADD returns the old value.
- * Readers increment by 1 and see a positive value when uncontended, negative
- * if there are writers (and maybe) readers waiting (in which case it goes to
- * sleep).
- *
- * The value of WAITING_BIAS supports up to 32766 waiting processes. This can
- * be extended to 65534 by manually checking the whole MSW rather than relying
- * on the S flag.
- *
- * The value of ACTIVE_BIAS supports up to 65535 active processes.
- *
- * This should be totally fair - if anything is waiting, a process that wants a
- * lock will go to the back of the queue. When the currently active lock is
- * released, if there's a writer at the front of the queue, then that and only
- * that will be woken up; if there's a bunch of consequtive readers at the
- * front, then they'll all be woken up, but no other readers will be.
- */
-
-#ifndef _I386_RWSEM_H
-#define _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 *FASTCALL(rwsem_down_read_failed(struct rw_semaphore *sem));
-extern struct rw_semaphore *FASTCALL(rwsem_down_write_failed(struct rw_semaphore *sem));
-extern struct rw_semaphore *FASTCALL(rwsem_wake(struct rw_semaphore *));
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- signed long count;
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
-#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
-};
-
-/*
- * initialisation
- */
-#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
-}
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
- "# beginning down_read\n\t"
-LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value */
- " js 2f\n\t" /* jump if we weren't granted the lock */
- "1:\n\t"
- ".section .text.lock,\"ax\"\n"
- "2:\n\t"
- " pushl %%ecx\n\t"
- " pushl %%edx\n\t"
- " call rwsem_down_read_failed\n\t"
- " popl %%edx\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- ".previous"
- "# ending down_read\n\t"
- : "+m"(sem->count)
- : "a"(sem)
- : "memory", "cc");
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = RWSEM_ACTIVE_WRITE_BIAS;
- __asm__ __volatile__(
- "# beginning down_write\n\t"
-LOCK_PREFIX " xadd %0,(%%eax)\n\t" /* subtract 0x0000ffff, returns the old value */
- " testl %0,%0\n\t" /* was the count 0 before? */
- " jnz 2f\n\t" /* jump if we weren't granted the lock */
- "1:\n\t"
- ".section .text.lock,\"ax\"\n"
- "2:\n\t"
- " pushl %%ecx\n\t"
- " call rwsem_down_write_failed\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- ".previous\n"
- "# ending down_write"
- : "+d"(tmp), "+m"(sem->count)
- : "a"(sem)
- : "memory", "cc");
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- __s32 tmp = -RWSEM_ACTIVE_READ_BIAS;
- __asm__ __volatile__(
- "# beginning __up_read\n\t"
-LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtracts 1, returns the old value */
- " js 2f\n\t" /* jump if the lock is being waited upon */
- "1:\n\t"
- ".section .text.lock,\"ax\"\n"
- "2:\n\t"
- " decw %%dx\n\t" /* do nothing if still outstanding active readers */
- " jnz 1b\n\t"
- " pushl %%ecx\n\t"
- " call rwsem_wake\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- ".previous\n"
- "# ending __up_read\n"
- : "+m"(sem->count), "+d"(tmp)
- : "a"(sem)
- : "memory", "cc");
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
- "# beginning __up_write\n\t"
- " movl %2,%%edx\n\t"
-LOCK_PREFIX " xaddl %%edx,(%%eax)\n\t" /* tries to transition 0xffff0001 -> 0x00000000 */
- " jnz 2f\n\t" /* jump if the lock is being waited upon */
- "1:\n\t"
- ".section .text.lock,\"ax\"\n"
- "2:\n\t"
- " decw %%dx\n\t" /* did the active count reduce to 0? */
- " jnz 1b\n\t" /* jump back if not */
- " pushl %%ecx\n\t"
- " call rwsem_wake\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- ".previous\n"
- "# ending __up_write\n"
- : "+m"(sem->count)
- : "a"(sem), "i"(-RWSEM_ACTIVE_WRITE_BIAS)
- : "memory", "cc", "edx");
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
-LOCK_PREFIX "addl %1,%0"
- :"=m"(sem->count)
- :"ir"(delta), "m"(sem->count));
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
- int tmp = delta;
-
- __asm__ __volatile__(
-LOCK_PREFIX "xadd %0,(%2)"
- : "+r"(tmp), "=m"(sem->count)
- : "r"(sem), "m"(sem->count)
- : "memory");
-
- return tmp+delta;
-}
-
-#endif /* __KERNEL__ */
-#endif /* _I386_RWSEM_H */
diff -urN 2.4.5pre3/include/asm-i386/rwsem_xchgadd.h rwsem/include/asm-i386/rwsem_xchgadd.h
--- 2.4.5pre3/include/asm-i386/rwsem_xchgadd.h Thu Jan 1 01:00:00 1970
+++ rwsem/include/asm-i386/rwsem_xchgadd.h Wed May 16 23:26:06 2001
@@ -0,0 +1,93 @@
+#ifndef _X86_RWSEM_XCHGADD_H
+#define _X86_RWSEM_XCHGADD_H
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+ __asm__ __volatile__(LOCK "incl %0\n\t"
+ "js 2f\n"
+ "1:\n"
+ ".section .text.lock,\"ax\"\n"
+ "2:\t"
+ "pushl %%edx\n\t"
+ "pushl %%ecx\n\t"
+ "movl %2, %%edx\n\t"
+ "call rwsem_down_failed\n\t"
+ "popl %%ecx\n\t"
+ "popl %%edx\n\t"
+ "jmp 1b\n"
+ ".previous"
+ : "+m" (sem->count)
+ : "a" (sem), "i" (RWSEM_READ_BLOCKING_BIAS)
+ : "memory", "cc");
+}
+
+static inline void __down_write(struct rw_semaphore *sem)
+{
+ long count;
+
+ count = RWSEM_WRITE_BIAS + RWSEM_READ_BIAS;
+ __asm__ __volatile(LOCK "xaddl %0, %1\n\t"
+ "testl %0,%0\n\t"
+ "jnz 2f\n"
+ "1:\n"
+ ".section .text.lock,\"ax\"\n"
+ "2:\t"
+ "pushl %%ecx\n\t"
+ "movl %3, %%edx\n\t"
+ "call rwsem_down_failed\n\t"
+ "popl %%ecx\n\t"
+ "jmp 1b\n"
+ ".previous"
+ : "+d" (count), "+m" (sem->count)
+ : "a" (sem), "i" (RWSEM_WRITE_BLOCKING_BIAS)
+ : "memory", "cc");
+}
+
+static inline void __up_read(struct rw_semaphore *sem)
+{
+ long count;
+
+ count = -RWSEM_READ_BIAS;
+ __asm__ __volatile__(LOCK "xaddl %0, %1\n\t"
+ "js 2f\n"
+ "1:\n"
+ ".section .text.lock,\"ax\"\n"
+ "2:\t"
+ "cmpw $1, %w0\n\t"
+ "jnz 1b\n\t"
+ "pushl %%ecx\n\t"
+ "call rwsem_wake\n\t"
+ "popl %%ecx\n\t"
+ "jmp 1b\n"
+ ".previous"
+ : "+d" (count), "+m" (sem->count)
+ : "a" (sem)
+ : "memory", "cc");
+}
+static inline void __up_write(struct rw_semaphore *sem)
+{
+ __asm__ __volatile__(LOCK "subl %2, %0\n\t"
+ "js 2f\n"
+ "1:\n"
+ ".section .text.lock,\"ax\"\n"
+ "2:\t"
+ "pushl %%edx\n\t"
+ "pushl %%ecx\n\t"
+ "call rwsem_wake\n\t"
+ "popl %%ecx\n\t"
+ "popl %%edx\n\t"
+ "jmp 1b\n"
+ ".previous"
+ : "+m" (sem->count)
+ : "a" (sem), "i" (RWSEM_READ_BIAS + RWSEM_WRITE_BIAS)
+ : "memory", "cc");
+}
+
+static inline long rwsem_xchgadd(long value, long * count)
+{
+ __asm__ __volatile__(LOCK "xaddl %0,%1"
+ : "+r" (value), "+m" (*count));
+ return value;
+}
+
+#endif
diff -urN 2.4.5pre3/include/linux/rwsem-spinlock.h rwsem/include/linux/rwsem-spinlock.h
--- 2.4.5pre3/include/linux/rwsem-spinlock.h Fri May 11 04:56:08 2001
+++ rwsem/include/linux/rwsem-spinlock.h Thu Jan 1 01:00:00 1970
@@ -1,62 +0,0 @@
-/* rwsem-spinlock.h: fallback C implementation
- *
- * Copyright (c) 2001 David Howells (dhowells@redhat.com).
- * - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de>
- * - Derived also from comments by Linus
- */
-
-#ifndef _LINUX_RWSEM_SPINLOCK_H
-#define _LINUX_RWSEM_SPINLOCK_H
-
-#ifndef _LINUX_RWSEM_H
-#error please dont include asm/rwsem-spinlock.h directly, use linux/rwsem.h instead
-#endif
-
-#include <linux/spinlock.h>
-#include <linux/list.h>
-
-#ifdef __KERNEL__
-
-#include <linux/types.h>
-
-struct rwsem_waiter;
-
-/*
- * the rw-semaphore definition
- * - if activity is 0 then there are no active readers or writers
- * - if activity is +ve then that is the number of active readers
- * - if activity is -1 then there is one active writer
- * - if wait_list is not empty, then there are processes waiting for the semaphore
- */
-struct rw_semaphore {
- __s32 activity;
- spinlock_t wait_lock;
- struct list_head wait_list;
-#if RWSEM_DEBUG
- int debug;
-#endif
-};
-
-/*
- * initialisation
- */
-#if RWSEM_DEBUG
-#define __RWSEM_DEBUG_INIT , 0
-#else
-#define __RWSEM_DEBUG_INIT /* */
-#endif
-
-#define __RWSEM_INITIALIZER(name) \
-{ 0, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __RWSEM_DEBUG_INIT }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern void FASTCALL(init_rwsem(struct rw_semaphore *sem));
-extern void FASTCALL(__down_read(struct rw_semaphore *sem));
-extern void FASTCALL(__down_write(struct rw_semaphore *sem));
-extern void FASTCALL(__up_read(struct rw_semaphore *sem));
-extern void FASTCALL(__up_write(struct rw_semaphore *sem));
-
-#endif /* __KERNEL__ */
-#endif /* _LINUX_RWSEM_SPINLOCK_H */
diff -urN 2.4.5pre3/include/linux/rwsem.h rwsem/include/linux/rwsem.h
--- 2.4.5pre3/include/linux/rwsem.h Fri May 11 04:56:08 2001
+++ rwsem/include/linux/rwsem.h Wed May 16 23:26:06 2001
@@ -1,79 +1,19 @@
-/* rwsem.h: R/W semaphores, public interface
- *
- * Written by David Howells (dhowells@redhat.com).
- * Derived from asm-i386/semaphore.h
- */
-
#ifndef _LINUX_RWSEM_H
#define _LINUX_RWSEM_H
-#include <linux/linkage.h>
-
-#define RWSEM_DEBUG 0
-
#ifdef __KERNEL__
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <asm/system.h>
-#include <asm/atomic.h>
+#include <linux/config.h>
-struct rw_semaphore;
+#undef RWSEM_DEBUG
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-#include <linux/rwsem-spinlock.h> /* use a generic implementation */
-#else
-#include <asm/rwsem.h> /* use an arch-specific implementation */
-#endif
-
-#ifndef rwsemtrace
-#if RWSEM_DEBUG
-extern void FASTCALL(rwsemtrace(struct rw_semaphore *sem, const char *str));
+#include <linux/rwsem_spinlock.h>
+#elif defined(CONFIG_RWSEM_XCHGADD)
+#include <linux/rwsem_xchgadd.h>
#else
-#define rwsemtrace(SEM,FMT)
+#include <asm/rwsem.h>
#endif
-#endif
-
-/*
- * lock for reading
- */
-static inline void down_read(struct rw_semaphore *sem)
-{
- rwsemtrace(sem,"Entering down_read");
- __down_read(sem);
- rwsemtrace(sem,"Leaving down_read");
-}
-
-/*
- * lock for writing
- */
-static inline void down_write(struct rw_semaphore *sem)
-{
- rwsemtrace(sem,"Entering down_write");
- __down_write(sem);
- rwsemtrace(sem,"Leaving down_write");
-}
-
-/*
- * release a read lock
- */
-static inline void up_read(struct rw_semaphore *sem)
-{
- rwsemtrace(sem,"Entering up_read");
- __up_read(sem);
- rwsemtrace(sem,"Leaving up_read");
-}
-
-/*
- * release a write lock
- */
-static inline void up_write(struct rw_semaphore *sem)
-{
- rwsemtrace(sem,"Entering up_write");
- __up_write(sem);
- rwsemtrace(sem,"Leaving up_write");
-}
-
#endif /* __KERNEL__ */
#endif /* _LINUX_RWSEM_H */
diff -urN 2.4.5pre3/include/linux/rwsem_spinlock.h rwsem/include/linux/rwsem_spinlock.h
--- 2.4.5pre3/include/linux/rwsem_spinlock.h Thu Jan 1 01:00:00 1970
+++ rwsem/include/linux/rwsem_spinlock.h Wed May 16 23:26:06 2001
@@ -0,0 +1,61 @@
+#ifndef _LINUX_RWSEM_SPINLOCK_H
+#define _LINUX_RWSEM_SPINLOCK_H
+
+#include <linux/compiler.h>
+
+struct rw_semaphore
+{
+ spinlock_t lock;
+ long count;
+#define RWSEM_READ_BIAS 1
+#define RWSEM_WRITE_BIAS (~(~0UL >> (BITS_PER_LONG>>1)))
+ struct list_head wait;
+#if RWSEM_DEBUG
+ long __magic;
+#endif
+};
+
+#if RWSEM_DEBUG
+#define __SEM_DEBUG_INIT(name) \
+ , (long)&(name).__magic
+#define RWSEM_MAGIC(x) \
+ do { \
+ if ((x) != (long)&(x)) { \
+ printk("rwsem bad magic %lx (should be %lx), ", \
+ (long)x, (long)&(x)); \
+ BUG(); \
+ } \
+ } while (0)
+#else
+#define __SEM_DEBUG_INIT(name)
+#define CHECK_MAGIC(x)
+#endif
+
+#define __RWSEM_INITIALIZER(name, count) \
+{ \
+ SPIN_LOCK_UNLOCKED, \
+ (count), \
+ LIST_HEAD_INIT((name).wait) \
+ __SEM_DEBUG_INIT(name) \
+}
+#define RWSEM_INITIALIZER(name) __RWSEM_INITIALIZER(name, 0)
+
+#define __DECLARE_RWSEM(name, count) \
+ struct rw_semaphore name = __RWSEM_INITIALIZER(name, count)
+#define DECLARE_RWSEM(name) __DECLARE_RWSEM(name, 0)
+#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM(name, RWSEM_READ_BIAS)
+#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM(name, RWSEM_WRITE_BIAS)
+
+#define RWSEM_READ_BLOCKING_BIAS (RWSEM_WRITE_BIAS-RWSEM_READ_BIAS)
+#define RWSEM_WRITE_BLOCKING_BIAS (0)
+
+#define RWSEM_READ_MASK (~RWSEM_WRITE_BIAS)
+#define RWSEM_WRITE_MASK (RWSEM_WRITE_BIAS)
+
+extern void FASTCALL(init_rwsem(struct rw_semaphore *));
+extern void FASTCALL(down_read(struct rw_semaphore *));
+extern void FASTCALL(down_write(struct rw_semaphore *));
+extern void FASTCALL(up_read(struct rw_semaphore *));
+extern void FASTCALL(up_write(struct rw_semaphore *));
+
+#endif _LINUX_RWSEM_SPINLOCK_H
diff -urN 2.4.5pre3/include/linux/rwsem_xchgadd.h rwsem/include/linux/rwsem_xchgadd.h
--- 2.4.5pre3/include/linux/rwsem_xchgadd.h Thu Jan 1 01:00:00 1970
+++ rwsem/include/linux/rwsem_xchgadd.h Wed May 16 23:26:06 2001
@@ -0,0 +1,102 @@
+#ifndef _LINUX_RWSEM_XCHGADD_H
+#define _LINUX_RWSEM_XCHGADD_H
+
+struct rw_semaphore
+{
+ long count;
+ spinlock_t lock;
+#define RWSEM_READ_BIAS 1
+#define RWSEM_WRITE_BIAS (~(~0UL >> (BITS_PER_LONG>>1)))
+ struct list_head wait;
+#if RWSEM_DEBUG
+ long __magic;
+#endif
+};
+
+#if RWSEM_DEBUG
+#define __SEM_DEBUG_INIT(name) \
+ , (int)&(name).__magic
+#define RWSEM_MAGIC(x) \
+ do { \
+ if ((x) != (long)&(x)) { \
+ printk("rwsem bad magic %lx (should be %lx), ", \
+ (long)x, (long)&(x)); \
+ BUG(); \
+ } \
+ } while (0)
+#else
+#define __SEM_DEBUG_INIT(name)
+#define CHECK_MAGIC(x)
+#endif
+
+#define __RWSEM_INITIALIZER(name, count) \
+{ \
+ (count), \
+ SPIN_LOCK_UNLOCKED, \
+ LIST_HEAD_INIT((name).wait) \
+ __SEM_DEBUG_INIT(name) \
+}
+#define RWSEM_INITIALIZER(name) __RWSEM_INITIALIZER(name, 0)
+
+#define __DECLARE_RWSEM(name, count) \
+ struct rw_semaphore name = __RWSEM_INITIALIZER(name, count)
+#define DECLARE_RWSEM(name) __DECLARE_RWSEM(name, 0)
+#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM(name, RWSEM_READ_BIAS)
+#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM(name, RWSEM_WRITE_BIAS+RWSEM_READ_BIAS)
+
+#define RWSEM_READ_BLOCKING_BIAS (RWSEM_WRITE_BIAS-RWSEM_READ_BIAS)
+#define RWSEM_WRITE_BLOCKING_BIAS (-RWSEM_READ_BIAS)
+
+#define RWSEM_READ_MASK (~RWSEM_WRITE_BIAS)
+#define RWSEM_WRITE_MASK (RWSEM_WRITE_BIAS)
+
+/*
+ * We return the semaphore itself from the C functions so we can pass it
+ * in %eax via regparm and we don't need to declare %eax clobbered by C.
+ * This is mostly for x86 but maybe other archs can make a use of it too.
+ * Idea is from David Howells <dhowells@redhat.com>.
+ */
+extern struct rw_semaphore * FASTCALL(rwsem_down_failed(struct rw_semaphore *, long));
+extern struct rw_semaphore * FASTCALL(rwsem_wake(struct rw_semaphore *));
+
+static inline void init_rwsem(struct rw_semaphore *sem)
+{
+ sem->count = 0;
+ spin_lock_init(&sem->lock);
+ INIT_LIST_HEAD(&sem->wait);
+#if RWSEM_DEBUG
+ sem->__magic = (long)&sem->__magic;
+#endif
+}
+
+#include <asm/rwsem_xchgadd.h>
+
+static inline void down_read(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ __down_read(sem);
+}
+
+static inline void down_write(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ __down_write(sem);
+}
+
+static inline void up_read(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ __up_read(sem);
+}
+
+static inline void up_write(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ __up_write(sem);
+}
+
+#endif /* _LINUX_RWSEM_XCHGADD_H */
diff -urN 2.4.5pre3/include/linux/sched.h rwsem/include/linux/sched.h
--- 2.4.5pre3/include/linux/sched.h Tue May 1 19:35:32 2001
+++ rwsem/include/linux/sched.h Wed May 16 23:26:06 2001
@@ -239,7 +239,7 @@
mm_users: ATOMIC_INIT(2), \
mm_count: ATOMIC_INIT(1), \
map_count: 1, \
- mmap_sem: __RWSEM_INITIALIZER(name.mmap_sem), \
+ mmap_sem: RWSEM_INITIALIZER(name.mmap_sem), \
page_table_lock: SPIN_LOCK_UNLOCKED, \
mmlist: LIST_HEAD_INIT(name.mmlist), \
}
diff -urN 2.4.5pre3/lib/Makefile rwsem/lib/Makefile
--- 2.4.5pre3/lib/Makefile Tue May 1 19:35:33 2001
+++ rwsem/lib/Makefile Wed May 16 23:26:06 2001
@@ -8,12 +8,12 @@
L_TARGET := lib.a
-export-objs := cmdline.o rwsem-spinlock.o rwsem.o
+export-objs := cmdline.o rwsem_spinlock.o rwsem_xchgadd.o
obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o
-obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
-obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
+obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem_spinlock.o
+obj-$(CONFIG_RWSEM_XCHGADD) += rwsem_xchgadd.o
ifneq ($(CONFIG_HAVE_DEC_LOCK),y)
obj-y += dec_and_lock.o
diff -urN 2.4.5pre3/lib/rwsem.c rwsem/lib/rwsem.c
--- 2.4.5pre3/lib/rwsem.c Tue May 1 19:35:33 2001
+++ rwsem/lib/rwsem.c Thu Jan 1 01:00:00 1970
@@ -1,210 +0,0 @@
-/* rwsem.c: R/W semaphores: contention handling functions
- *
- * Written by David Howells (dhowells@redhat.com).
- * Derived from arch/i386/kernel/semaphore.c
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/module.h>
-
-struct rwsem_waiter {
- struct list_head list;
- struct task_struct *task;
- unsigned int flags;
-#define RWSEM_WAITING_FOR_READ 0x00000001
-#define RWSEM_WAITING_FOR_WRITE 0x00000002
-};
-
-#if RWSEM_DEBUG
-#undef rwsemtrace
-void rwsemtrace(struct rw_semaphore *sem, const char *str)
-{
- printk("sem=%p\n",sem);
- printk("(sem)=%08lx\n",sem->count);
- if (sem->debug)
- printk("[%d] %s({%08lx})\n",current->pid,str,sem->count);
-}
-#endif
-
-/*
- * handle the lock being released whilst there are processes blocked on it that can now run
- * - if we come here, then:
- * - the 'active part' of the count (&0x0000ffff) reached zero but has been re-incremented
- * - the 'waiting part' of the count (&0xffff0000) is negative (and will still be so)
- * - there must be someone on the queue
- * - the spinlock must be held by the caller
- * - woken process blocks are discarded from the list after having flags zeroised
- */
-static inline struct rw_semaphore *__rwsem_do_wake(struct rw_semaphore *sem)
-{
- struct rwsem_waiter *waiter;
- struct list_head *next;
- signed long oldcount;
- int woken, loop;
-
- rwsemtrace(sem,"Entering __rwsem_do_wake");
-
- /* only wake someone up if we can transition the active part of the count from 0 -> 1 */
- try_again:
- oldcount = rwsem_atomic_update(RWSEM_ACTIVE_BIAS,sem) - RWSEM_ACTIVE_BIAS;
- if (oldcount & RWSEM_ACTIVE_MASK)
- goto undo;
-
- waiter = list_entry(sem->wait_list.next,struct rwsem_waiter,list);
-
- /* try to grant a single write lock if there's a writer at the front of the queue
- * - note we leave the 'active part' of the count incremented by 1 and the waiting part
- * incremented by 0x00010000
- */
- if (!(waiter->flags & RWSEM_WAITING_FOR_WRITE))
- goto readers_only;
-
- list_del(&waiter->list);
- waiter->flags = 0;
- wake_up_process(waiter->task);
- goto out;
-
- /* grant an infinite number of read locks to the readers at the front of the queue
- * - note we increment the 'active part' of the count by the number of readers (less one
- * for the activity decrement we've already done) before waking any processes up
- */
- readers_only:
- woken = 0;
- do {
- woken++;
-
- if (waiter->list.next==&sem->wait_list)
- break;
-
- waiter = list_entry(waiter->list.next,struct rwsem_waiter,list);
-
- } while (waiter->flags & RWSEM_WAITING_FOR_READ);
-
- loop = woken;
- woken *= RWSEM_ACTIVE_BIAS-RWSEM_WAITING_BIAS;
- woken -= RWSEM_ACTIVE_BIAS;
- rwsem_atomic_add(woken,sem);
-
- next = sem->wait_list.next;
- for (; loop>0; loop--) {
- waiter = list_entry(next,struct rwsem_waiter,list);
- next = waiter->list.next;
- waiter->flags = 0;
- wake_up_process(waiter->task);
- }
-
- sem->wait_list.next = next;
- next->prev = &sem->wait_list;
-
- out:
- rwsemtrace(sem,"Leaving __rwsem_do_wake");
- return sem;
-
- /* undo the change to count, but check for a transition 1->0 */
- undo:
- if (rwsem_atomic_update(-RWSEM_ACTIVE_BIAS,sem)!=0)
- goto out;
- goto try_again;
-}
-
-/*
- * wait for a lock to be granted
- */
-static inline struct rw_semaphore *rwsem_down_failed_common(struct rw_semaphore *sem,
- struct rwsem_waiter *waiter,
- __s32 adjustment)
-{
- struct task_struct *tsk = current;
- signed long count;
-
- set_task_state(tsk,TASK_UNINTERRUPTIBLE);
-
- /* set up my own style of waitqueue */
- spin_lock(&sem->wait_lock);
- waiter->task = tsk;
-
- list_add_tail(&waiter->list,&sem->wait_list);
-
- /* note that we're now waiting on the lock, but no longer actively read-locking */
- count = rwsem_atomic_update(adjustment,sem);
-
- /* if there are no longer active locks, wake the front queued process(es) up
- * - it might even be this process, since the waker takes a more active part
- */
- if (!(count & RWSEM_ACTIVE_MASK))
- sem = __rwsem_do_wake(sem);
-
- spin_unlock(&sem->wait_lock);
-
- /* wait to be given the lock */
- for (;;) {
- if (!waiter->flags)
- break;
- schedule();
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- }
-
- tsk->state = TASK_RUNNING;
-
- return sem;
-}
-
-/*
- * wait for the read lock to be granted
- */
-struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem)
-{
- struct rwsem_waiter waiter;
-
- rwsemtrace(sem,"Entering rwsem_down_read_failed");
-
- waiter.flags = RWSEM_WAITING_FOR_READ;
- rwsem_down_failed_common(sem,&waiter,RWSEM_WAITING_BIAS-RWSEM_ACTIVE_BIAS);
-
- rwsemtrace(sem,"Leaving rwsem_down_read_failed");
- return sem;
-}
-
-/*
- * wait for the write lock to be granted
- */
-struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem)
-{
- struct rwsem_waiter waiter;
-
- rwsemtrace(sem,"Entering rwsem_down_write_failed");
-
- waiter.flags = RWSEM_WAITING_FOR_WRITE;
- rwsem_down_failed_common(sem,&waiter,-RWSEM_ACTIVE_BIAS);
-
- rwsemtrace(sem,"Leaving rwsem_down_write_failed");
- return sem;
-}
-
-/*
- * handle waking up a waiter on the semaphore
- * - up_read has decremented the active part of the count if we come here
- */
-struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
-{
- rwsemtrace(sem,"Entering rwsem_wake");
-
- spin_lock(&sem->wait_lock);
-
- /* do nothing if list empty */
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem);
-
- spin_unlock(&sem->wait_lock);
-
- rwsemtrace(sem,"Leaving rwsem_wake");
-
- return sem;
-}
-
-EXPORT_SYMBOL_NOVERS(rwsem_down_read_failed);
-EXPORT_SYMBOL_NOVERS(rwsem_down_write_failed);
-EXPORT_SYMBOL_NOVERS(rwsem_wake);
-#if RWSEM_DEBUG
-EXPORT_SYMBOL(rwsemtrace);
-#endif
diff -urN 2.4.5pre3/lib/rwsem_spinlock.c rwsem/lib/rwsem_spinlock.c
--- 2.4.5pre3/lib/rwsem_spinlock.c Thu Jan 1 01:00:00 1970
+++ rwsem/lib/rwsem_spinlock.c Wed May 16 23:26:06 2001
@@ -0,0 +1,124 @@
+/*
+ * rw_semaphores generic spinlock version
+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <asm/semaphore.h>
+
+struct rwsem_wait_queue {
+ unsigned long retire;
+ struct task_struct * task;
+ struct list_head task_list;
+};
+
+static void FASTCALL(rwsem_down_failed(struct rw_semaphore *, long));
+static void rwsem_down_failed(struct rw_semaphore *sem, long retire)
+{
+ struct task_struct *tsk = current;
+ struct rwsem_wait_queue wait;
+
+ sem->count += retire;
+ wait.retire = retire;
+ wait.task = tsk;
+ INIT_LIST_HEAD(&wait.task_list);
+ list_add(&wait.task_list, &sem->wait);
+
+ do {
+ __set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&sem->lock);
+ schedule();
+ spin_lock(&sem->lock);
+ } while(wait.task_list.next);
+}
+
+static void FASTCALL(rwsem_wake(struct rw_semaphore *));
+static void rwsem_wake(struct rw_semaphore *sem)
+{
+ struct list_head * entry, * head = &sem->wait;
+ int last = 0;
+
+ while ((entry = head->prev) != head) {
+ struct rwsem_wait_queue * wait;
+
+ wait = list_entry(entry, struct rwsem_wait_queue, task_list);
+
+ if (wait->retire == RWSEM_WRITE_BLOCKING_BIAS) {
+ if (sem->count & RWSEM_READ_MASK)
+ break;
+ last = 1;
+ }
+
+ /* convert write lock into read lock when read become active */
+ sem->count -= wait->retire;
+ list_del(entry);
+ entry->next = NULL;
+ wake_up_process(wait->task);
+
+ if (last)
+ break;
+ }
+}
+
+void init_rwsem(struct rw_semaphore *sem)
+{
+ spin_lock_init(&sem->lock);
+ sem->count = 0;
+ INIT_LIST_HEAD(&sem->wait);
+#if RWSEM_DEBUG
+ sem->__magic = (long)&sem->__magic;
+#endif
+}
+
+void down_read(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ spin_lock(&sem->lock);
+ sem->count += RWSEM_READ_BIAS;
+ if (__builtin_expect(sem->count, 0) < 0)
+ rwsem_down_failed(sem, RWSEM_READ_BLOCKING_BIAS);
+ spin_unlock(&sem->lock);
+}
+
+void down_write(struct rw_semaphore *sem)
+{
+ long count;
+ CHECK_MAGIC(sem->__magic);
+
+ spin_lock(&sem->lock);
+ count = sem->count;
+ sem->count += RWSEM_WRITE_BIAS;
+ if (__builtin_expect(count, 0))
+ rwsem_down_failed(sem, RWSEM_WRITE_BLOCKING_BIAS);
+ spin_unlock(&sem->lock);
+}
+
+void up_read(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ spin_lock(&sem->lock);
+ sem->count -= RWSEM_READ_BIAS;
+ if (__builtin_expect(sem->count < 0 && !(sem->count & RWSEM_READ_MASK), 0))
+ rwsem_wake(sem);
+ spin_unlock(&sem->lock);
+}
+
+void up_write(struct rw_semaphore *sem)
+{
+ CHECK_MAGIC(sem->__magic);
+
+ spin_lock(&sem->lock);
+ sem->count -= RWSEM_WRITE_BIAS;
+ if (__builtin_expect(sem->count, 0))
+ rwsem_wake(sem);
+ spin_unlock(&sem->lock);
+}
+
+EXPORT_SYMBOL(init_rwsem);
+EXPORT_SYMBOL(down_read);
+EXPORT_SYMBOL(down_write);
+EXPORT_SYMBOL(up_read);
+EXPORT_SYMBOL(up_write);
diff -urN 2.4.5pre3/lib/rwsem_xchgadd.c rwsem/lib/rwsem_xchgadd.c
--- 2.4.5pre3/lib/rwsem_xchgadd.c Thu Jan 1 01:00:00 1970
+++ rwsem/lib/rwsem_xchgadd.c Wed May 16 23:26:06 2001
@@ -0,0 +1,92 @@
+/*
+ * rw_semaphores xchgadd version
+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <asm/semaphore.h>
+
+struct rwsem_wait_queue {
+ unsigned long retire;
+ struct task_struct * task;
+ struct list_head task_list;
+};
+
+static void FASTCALL(__rwsem_wake(struct rw_semaphore *));
+static void __rwsem_wake(struct rw_semaphore *sem)
+{
+ struct list_head * entry, * head = &sem->wait;
+ int wake_write = 0, wake_read = 0;
+
+ while ((entry = head->prev) != head) {
+ struct rwsem_wait_queue * wait;
+ long count;
+
+ wait = list_entry(entry, struct rwsem_wait_queue, task_list);
+
+ if (wait->retire == RWSEM_WRITE_BLOCKING_BIAS) {
+ if (wake_read)
+ break;
+ wake_write = 1;
+ }
+
+ again:
+ count = rwsem_xchgadd(-wait->retire, &sem->count);
+ if (!wake_read && (count & RWSEM_READ_MASK)) {
+ count = rwsem_xchgadd(wait->retire, &sem->count);
+ if ((count & RWSEM_READ_MASK) == 1)
+ goto again;
+ break;
+ }
+
+ list_del(entry);
+ entry->next = NULL;
+ wake_up_process(wait->task);
+
+ if (wake_write)
+ break;
+ wake_read = 1;
+ }
+}
+
+struct rw_semaphore * rwsem_down_failed(struct rw_semaphore *sem, long retire)
+{
+ struct task_struct *tsk = current;
+ struct rwsem_wait_queue wait;
+ long count;
+
+ wait.retire = retire;
+ wait.task = tsk;
+ INIT_LIST_HEAD(&wait.task_list);
+
+ spin_lock(&sem->lock);
+ list_add(&wait.task_list, &sem->wait);
+
+ count = rwsem_xchgadd(retire, &sem->count);
+ if ((count & RWSEM_READ_MASK) == 1)
+ __rwsem_wake(sem);
+
+ while (wait.task_list.next) {
+ __set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&sem->lock);
+ schedule();
+ spin_lock(&sem->lock);
+ }
+
+ spin_unlock(&sem->lock);
+
+ return sem;
+}
+
+struct rw_semaphore * rwsem_wake(struct rw_semaphore *sem)
+{
+ spin_lock(&sem->lock);
+ __rwsem_wake(sem);
+ spin_unlock(&sem->lock);
+
+ return sem;
+}
+
+EXPORT_SYMBOL_NOVERS(rwsem_down_failed);
+EXPORT_SYMBOL_NOVERS(rwsem_wake);