Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc

* 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc:
  Remove DEBUG_SEMAPHORE from Kconfig
  Improve semaphore documentation
  Simplify semaphore implementation
  Add down_timeout and change ACPI to use it
  Introduce down_killable()
  Generic semaphore implementation
  Add semaphore.h to kernel_lock.c
  Fix quota.h includes

4 files changed, 1 insertions, 187 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index eef557dc46c3..80db357b0a42 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -265,16 +265,6 @@ config DEBUG_MUTEXES
          This feature allows mutex semantics violations to be detected and
          reported.
 
-config DEBUG_SEMAPHORE
-        bool "Semaphore debugging"
-        depends on DEBUG_KERNEL
-        depends on ALPHA || FRV
-        default n
-        help
-          If you say Y here then semaphore processing will issue lots of
-          verbose debugging messages.  If you suspect a semaphore problem or a
-          kernel hacker asks for this option then say Y.  Otherwise say N.
-
 config DEBUG_LOCK_ALLOC
         bool "Lock debugging: detect incorrect freeing of live locks"
         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
diff --git a/lib/Makefile b/lib/Makefile
index 23de261a4c83..28dba90d5020 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -29,7 +29,6 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
-lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o
 lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
 obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
 obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c
index 812dbf00844b..fbc11a336bc5 100644
--- a/lib/kernel_lock.c
+++ b/lib/kernel_lock.c
@@ -8,6 +8,7 @@
 #include <linux/smp_lock.h>
 #include <linux/module.h>
 #include <linux/kallsyms.h>
+#include <asm/semaphore.h>
 
 /*
  * The 'big kernel semaphore'
diff --git a/lib/semaphore-sleepers.c b/lib/semaphore-sleepers.c
deleted file mode 100644
index 0198782cdacb..000000000000
--- a/lib/semaphore-sleepers.c
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * i386 and x86-64 semaphore implementation.
- *
- * (C) Copyright 1999 Linus Torvalds
- *
- * Portions Copyright 1999 Red Hat, Inc.
- *
- *      This program is free software; you can redistribute it and/or
- *      modify it under the terms of the GNU General Public License
- *      as published by the Free Software Foundation; either version
- *      2 of the License, or (at your option) any later version.
- *
- * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
- */
-#include <linux/sched.h>
-#include <linux/err.h>
-#include <linux/init.h>
-#include <asm/semaphore.h>
-
-/*
- * Semaphores are implemented using a two-way counter:
- * The "count" variable is decremented for each process
- * that tries to acquire the semaphore, while the "sleeping"
- * variable is a count of such acquires.
- *
- * Notably, the inline "up()" and "down()" functions can
- * efficiently test if they need to do any extra work (up
- * needs to do something only if count was negative before
- * the increment operation.
- *
- * "sleeping" and the contention routine ordering is protected
- * by the spinlock in the semaphore's waitqueue head.
- *
- * Note that these functions are only called when there is
- * contention on the lock, and as such all this is the
- * "non-critical" part of the whole semaphore business. The
- * critical part is the inline stuff in <asm/semaphore.h>
- * where we want to avoid any extra jumps and calls.
- */
-
-/*
- * Logic:
- *  - only on a boundary condition do we need to care. When we go
- *    from a negative count to a non-negative, we wake people up.
- *  - when we go from a non-negative count to a negative do we
- *    (a) synchronize with the "sleeper" count and (b) make sure
- *    that we're on the wakeup list before we synchronize so that
- *    we cannot lose wakeup events.
- */
-
-void __up(struct semaphore *sem)
-{
-        wake_up(&sem->wait);
-}
-
-void __sched __down(struct semaphore *sem)
-{
-        struct task_struct *tsk = current;
-        DECLARE_WAITQUEUE(wait, tsk);
-        unsigned long flags;
-
-        tsk->state = TASK_UNINTERRUPTIBLE;
-        spin_lock_irqsave(&sem->wait.lock, flags);
-        add_wait_queue_exclusive_locked(&sem->wait, &wait);
-
-        sem->sleepers++;
-        for (;;) {
-                int sleepers = sem->sleepers;
-
-                /*
-                 * Add "everybody else" into it. They aren't
-                 * playing, because we own the spinlock in
-                 * the wait_queue_head.
-                 */
-                if (!atomic_add_negative(sleepers - 1, &sem->count)) {
-                        sem->sleepers = 0;
-                        break;
-                }
-                sem->sleepers = 1;      /* us - see -1 above */
-                spin_unlock_irqrestore(&sem->wait.lock, flags);
-
-                schedule();
-
-                spin_lock_irqsave(&sem->wait.lock, flags);
-                tsk->state = TASK_UNINTERRUPTIBLE;
-        }
-        remove_wait_queue_locked(&sem->wait, &wait);
-        wake_up_locked(&sem->wait);
-        spin_unlock_irqrestore(&sem->wait.lock, flags);
-        tsk->state = TASK_RUNNING;
-}
-
-int __sched __down_interruptible(struct semaphore *sem)
-{
-        int retval = 0;
-        struct task_struct *tsk = current;
-        DECLARE_WAITQUEUE(wait, tsk);
-        unsigned long flags;
-
-        tsk->state = TASK_INTERRUPTIBLE;
-        spin_lock_irqsave(&sem->wait.lock, flags);
-        add_wait_queue_exclusive_locked(&sem->wait, &wait);
-
-        sem->sleepers++;
-        for (;;) {
-                int sleepers = sem->sleepers;
-
-                /*
-                 * With signals pending, this turns into
-                 * the trylock failure case - we won't be
-                 * sleeping, and we* can't get the lock as
-                 * it has contention. Just correct the count
-                 * and exit.
-                 */
-                if (signal_pending(current)) {
-                        retval = -EINTR;
-                        sem->sleepers = 0;
-                        atomic_add(sleepers, &sem->count);
-                        break;
-                }
-
-                /*
-                 * Add "everybody else" into it. They aren't
-                 * playing, because we own the spinlock in
-                 * wait_queue_head. The "-1" is because we're
-                 * still hoping to get the semaphore.
-                 */
-                if (!atomic_add_negative(sleepers - 1, &sem->count)) {
-                        sem->sleepers = 0;
-                        break;
-                }
-                sem->sleepers = 1;      /* us - see -1 above */
-                spin_unlock_irqrestore(&sem->wait.lock, flags);
-
-                schedule();
-
-                spin_lock_irqsave(&sem->wait.lock, flags);
-                tsk->state = TASK_INTERRUPTIBLE;
-        }
-        remove_wait_queue_locked(&sem->wait, &wait);
-        wake_up_locked(&sem->wait);
-        spin_unlock_irqrestore(&sem->wait.lock, flags);
-
-        tsk->state = TASK_RUNNING;
-        return retval;
-}
-
-/*
- * Trylock failed - make sure we correct for
- * having decremented the count.
- *
- * We could have done the trylock with a
- * single "cmpxchg" without failure cases,
- * but then it wouldn't work on a 386.
- */
-int __down_trylock(struct semaphore *sem)
-{
-        int sleepers;
-        unsigned long flags;
-
-        spin_lock_irqsave(&sem->wait.lock, flags);
-        sleepers = sem->sleepers + 1;
-        sem->sleepers = 0;
-
-        /*
-         * Add "everybody else" and us into it. They aren't
-         * playing, because we own the spinlock in the
-         * wait_queue_head.
-         */
-        if (!atomic_add_negative(sleepers, &sem->count)) {
-                wake_up_locked(&sem->wait);
-        }
-
-        spin_unlock_irqrestore(&sem->wait.lock, flags);
-        return 1;
-}