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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-14 16:30:30 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-14 16:30:30 +0900
commit5e30025a319910695f5010dc0fb53a23299da14d (patch)
tree4292bcf78de221c7de1774ccf5ad0ac5a9315c26 /lib
parent7971e23a66c94f1b9bd2d64a3e86dfbfa8c60121 (diff)
parent90d3839b90fe379557dae4a44735a6af78f42885 (diff)
downloadop-kernel-dev-5e30025a319910695f5010dc0fb53a23299da14d.zip
op-kernel-dev-5e30025a319910695f5010dc0fb53a23299da14d.tar.gz
Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core locking changes from Ingo Molnar: "The biggest changes: - add lockdep support for seqcount/seqlocks structures, this unearthed both bugs and required extra annotation. - move the various kernel locking primitives to the new kernel/locking/ directory" * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) block: Use u64_stats_init() to initialize seqcounts locking/lockdep: Mark __lockdep_count_forward_deps() as static lockdep/proc: Fix lock-time avg computation locking/doc: Update references to kernel/mutex.c ipv6: Fix possible ipv6 seqlock deadlock cpuset: Fix potential deadlock w/ set_mems_allowed seqcount: Add lockdep functionality to seqcount/seqlock structures net: Explicitly initialize u64_stats_sync structures for lockdep locking: Move the percpu-rwsem code to kernel/locking/ locking: Move the lglocks code to kernel/locking/ locking: Move the rwsem code to kernel/locking/ locking: Move the rtmutex code to kernel/locking/ locking: Move the semaphore core to kernel/locking/ locking: Move the spinlock code to kernel/locking/ locking: Move the lockdep code to kernel/locking/ locking: Move the mutex code to kernel/locking/ hung_task debugging: Add tracepoint to report the hang x86/locking/kconfig: Update paravirt spinlock Kconfig description lockstat: Report avg wait and hold times lockdep, x86/alternatives: Drop ancient lockdep fixup message ...
Diffstat (limited to 'lib')
-rw-r--r--lib/Makefile4
-rw-r--r--lib/percpu-rwsem.c165
-rw-r--r--lib/rwsem-spinlock.c296
-rw-r--r--lib/rwsem.c293
-rw-r--r--lib/spinlock_debug.c302
5 files changed, 0 insertions, 1060 deletions
diff --git a/lib/Makefile b/lib/Makefile
index bb016e1..d480a8c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -42,10 +42,6 @@ obj-$(CONFIG_GENERIC_PCI_IOMAP) += pci_iomap.o
obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
obj-$(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_PERCPU_RWSEM) += percpu-rwsem.o
CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
diff --git a/lib/percpu-rwsem.c b/lib/percpu-rwsem.c
deleted file mode 100644
index 652a8ee..0000000
--- a/lib/percpu-rwsem.c
+++ /dev/null
@@ -1,165 +0,0 @@
-#include <linux/atomic.h>
-#include <linux/rwsem.h>
-#include <linux/percpu.h>
-#include <linux/wait.h>
-#include <linux/lockdep.h>
-#include <linux/percpu-rwsem.h>
-#include <linux/rcupdate.h>
-#include <linux/sched.h>
-#include <linux/errno.h>
-
-int __percpu_init_rwsem(struct percpu_rw_semaphore *brw,
- const char *name, struct lock_class_key *rwsem_key)
-{
- brw->fast_read_ctr = alloc_percpu(int);
- if (unlikely(!brw->fast_read_ctr))
- return -ENOMEM;
-
- /* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
- __init_rwsem(&brw->rw_sem, name, rwsem_key);
- atomic_set(&brw->write_ctr, 0);
- atomic_set(&brw->slow_read_ctr, 0);
- init_waitqueue_head(&brw->write_waitq);
- return 0;
-}
-
-void percpu_free_rwsem(struct percpu_rw_semaphore *brw)
-{
- free_percpu(brw->fast_read_ctr);
- brw->fast_read_ctr = NULL; /* catch use after free bugs */
-}
-
-/*
- * This is the fast-path for down_read/up_read, it only needs to ensure
- * there is no pending writer (atomic_read(write_ctr) == 0) and inc/dec the
- * fast per-cpu counter. The writer uses synchronize_sched_expedited() to
- * serialize with the preempt-disabled section below.
- *
- * The nontrivial part is that we should guarantee acquire/release semantics
- * in case when
- *
- * R_W: down_write() comes after up_read(), the writer should see all
- * changes done by the reader
- * or
- * W_R: down_read() comes after up_write(), the reader should see all
- * changes done by the writer
- *
- * If this helper fails the callers rely on the normal rw_semaphore and
- * atomic_dec_and_test(), so in this case we have the necessary barriers.
- *
- * But if it succeeds we do not have any barriers, atomic_read(write_ctr) or
- * __this_cpu_add() below can be reordered with any LOAD/STORE done by the
- * reader inside the critical section. See the comments in down_write and
- * up_write below.
- */
-static bool update_fast_ctr(struct percpu_rw_semaphore *brw, unsigned int val)
-{
- bool success = false;
-
- preempt_disable();
- if (likely(!atomic_read(&brw->write_ctr))) {
- __this_cpu_add(*brw->fast_read_ctr, val);
- success = true;
- }
- preempt_enable();
-
- return success;
-}
-
-/*
- * Like the normal down_read() this is not recursive, the writer can
- * come after the first percpu_down_read() and create the deadlock.
- *
- * Note: returns with lock_is_held(brw->rw_sem) == T for lockdep,
- * percpu_up_read() does rwsem_release(). This pairs with the usage
- * of ->rw_sem in percpu_down/up_write().
- */
-void percpu_down_read(struct percpu_rw_semaphore *brw)
-{
- might_sleep();
- if (likely(update_fast_ctr(brw, +1))) {
- rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 0, _RET_IP_);
- return;
- }
-
- down_read(&brw->rw_sem);
- atomic_inc(&brw->slow_read_ctr);
- /* avoid up_read()->rwsem_release() */
- __up_read(&brw->rw_sem);
-}
-
-void percpu_up_read(struct percpu_rw_semaphore *brw)
-{
- rwsem_release(&brw->rw_sem.dep_map, 1, _RET_IP_);
-
- if (likely(update_fast_ctr(brw, -1)))
- return;
-
- /* false-positive is possible but harmless */
- if (atomic_dec_and_test(&brw->slow_read_ctr))
- wake_up_all(&brw->write_waitq);
-}
-
-static int clear_fast_ctr(struct percpu_rw_semaphore *brw)
-{
- unsigned int sum = 0;
- int cpu;
-
- for_each_possible_cpu(cpu) {
- sum += per_cpu(*brw->fast_read_ctr, cpu);
- per_cpu(*brw->fast_read_ctr, cpu) = 0;
- }
-
- return sum;
-}
-
-/*
- * A writer increments ->write_ctr to force the readers to switch to the
- * slow mode, note the atomic_read() check in update_fast_ctr().
- *
- * After that the readers can only inc/dec the slow ->slow_read_ctr counter,
- * ->fast_read_ctr is stable. Once the writer moves its sum into the slow
- * counter it represents the number of active readers.
- *
- * Finally the writer takes ->rw_sem for writing and blocks the new readers,
- * then waits until the slow counter becomes zero.
- */
-void percpu_down_write(struct percpu_rw_semaphore *brw)
-{
- /* tell update_fast_ctr() there is a pending writer */
- atomic_inc(&brw->write_ctr);
- /*
- * 1. Ensures that write_ctr != 0 is visible to any down_read/up_read
- * so that update_fast_ctr() can't succeed.
- *
- * 2. Ensures we see the result of every previous this_cpu_add() in
- * update_fast_ctr().
- *
- * 3. Ensures that if any reader has exited its critical section via
- * fast-path, it executes a full memory barrier before we return.
- * See R_W case in the comment above update_fast_ctr().
- */
- synchronize_sched_expedited();
-
- /* exclude other writers, and block the new readers completely */
- down_write(&brw->rw_sem);
-
- /* nobody can use fast_read_ctr, move its sum into slow_read_ctr */
- atomic_add(clear_fast_ctr(brw), &brw->slow_read_ctr);
-
- /* wait for all readers to complete their percpu_up_read() */
- wait_event(brw->write_waitq, !atomic_read(&brw->slow_read_ctr));
-}
-
-void percpu_up_write(struct percpu_rw_semaphore *brw)
-{
- /* release the lock, but the readers can't use the fast-path */
- up_write(&brw->rw_sem);
- /*
- * Insert the barrier before the next fast-path in down_read,
- * see W_R case in the comment above update_fast_ctr().
- */
- synchronize_sched_expedited();
- /* the last writer unblocks update_fast_ctr() */
- atomic_dec(&brw->write_ctr);
-}
diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
deleted file mode 100644
index 9be8a91..0000000
--- a/lib/rwsem-spinlock.c
+++ /dev/null
@@ -1,296 +0,0 @@
-/* rwsem-spinlock.c: R/W semaphores: contention handling functions for
- * generic spinlock implementation
- *
- * Copyright (c) 2001 David Howells (dhowells@redhat.com).
- * - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
- * - Derived also from comments by Linus
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/export.h>
-
-enum rwsem_waiter_type {
- RWSEM_WAITING_FOR_WRITE,
- RWSEM_WAITING_FOR_READ
-};
-
-struct rwsem_waiter {
- struct list_head list;
- struct task_struct *task;
- enum rwsem_waiter_type type;
-};
-
-int rwsem_is_locked(struct rw_semaphore *sem)
-{
- int ret = 1;
- unsigned long flags;
-
- if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) {
- ret = (sem->activity != 0);
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
- }
- return ret;
-}
-EXPORT_SYMBOL(rwsem_is_locked);
-
-/*
- * initialise the semaphore
- */
-void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held semaphore:
- */
- debug_check_no_locks_freed((void *)sem, sizeof(*sem));
- lockdep_init_map(&sem->dep_map, name, key, 0);
-#endif
- sem->activity = 0;
- raw_spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-EXPORT_SYMBOL(__init_rwsem);
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here, then:
- * - the 'active count' _reached_ zero
- * - the 'waiting count' is non-zero
- * - the spinlock must be held by the caller
- * - woken process blocks are discarded from the list after having task zeroed
- * - writers are only woken if wakewrite is non-zero
- */
-static inline struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
-{
- struct rwsem_waiter *waiter;
- struct task_struct *tsk;
- int woken;
-
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-
- if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
- if (wakewrite)
- /* Wake up a writer. Note that we do not grant it the
- * lock - it will have to acquire it when it runs. */
- wake_up_process(waiter->task);
- goto out;
- }
-
- /* grant an infinite number of read locks to the front of the queue */
- woken = 0;
- do {
- struct list_head *next = waiter->list.next;
-
- list_del(&waiter->list);
- tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- woken++;
- if (next == &sem->wait_list)
- break;
- waiter = list_entry(next, struct rwsem_waiter, list);
- } while (waiter->type != RWSEM_WAITING_FOR_WRITE);
-
- sem->activity += woken;
-
- out:
- return sem;
-}
-
-/*
- * wake a single writer
- */
-static inline struct rw_semaphore *
-__rwsem_wake_one_writer(struct rw_semaphore *sem)
-{
- struct rwsem_waiter *waiter;
-
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
- wake_up_process(waiter->task);
-
- return sem;
-}
-
-/*
- * get a read lock on the semaphore
- */
-void __sched __down_read(struct rw_semaphore *sem)
-{
- struct rwsem_waiter waiter;
- struct task_struct *tsk;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
- /* granted */
- sem->activity++;
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
- goto out;
- }
-
- tsk = current;
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-
- /* set up my own style of waitqueue */
- waiter.task = tsk;
- waiter.type = RWSEM_WAITING_FOR_READ;
- get_task_struct(tsk);
-
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we don't need to touch the semaphore struct anymore */
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- /* wait to be given the lock */
- for (;;) {
- if (!waiter.task)
- break;
- schedule();
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- }
-
- tsk->state = TASK_RUNNING;
- out:
- ;
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-int __down_read_trylock(struct rw_semaphore *sem)
-{
- unsigned long flags;
- int ret = 0;
-
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
- /* granted */
- sem->activity++;
- ret = 1;
- }
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return ret;
-}
-
-/*
- * get a write lock on the semaphore
- */
-void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
- struct rwsem_waiter waiter;
- struct task_struct *tsk;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- /* set up my own style of waitqueue */
- tsk = current;
- waiter.task = tsk;
- waiter.type = RWSEM_WAITING_FOR_WRITE;
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* wait for someone to release the lock */
- for (;;) {
- /*
- * That is the key to support write lock stealing: allows the
- * task already on CPU to get the lock soon rather than put
- * itself into sleep and waiting for system woke it or someone
- * else in the head of the wait list up.
- */
- if (sem->activity == 0)
- break;
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
- schedule();
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
- }
- /* got the lock */
- sem->activity = -1;
- list_del(&waiter.list);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-void __sched __down_write(struct rw_semaphore *sem)
-{
- __down_write_nested(sem, 0);
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-int __down_write_trylock(struct rw_semaphore *sem)
-{
- unsigned long flags;
- int ret = 0;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (sem->activity == 0) {
- /* got the lock */
- sem->activity = -1;
- ret = 1;
- }
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return ret;
-}
-
-/*
- * release a read lock on the semaphore
- */
-void __up_read(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (--sem->activity == 0 && !list_empty(&sem->wait_list))
- sem = __rwsem_wake_one_writer(sem);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-/*
- * release a write lock on the semaphore
- */
-void __up_write(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- sem->activity = 0;
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, 1);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-/*
- * downgrade a write lock into a read lock
- * - just wake up any readers at the front of the queue
- */
-void __downgrade_write(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- sem->activity = 1;
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, 0);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
diff --git a/lib/rwsem.c b/lib/rwsem.c
deleted file mode 100644
index 19c5fa9..0000000
--- a/lib/rwsem.c
+++ /dev/null
@@ -1,293 +0,0 @@
-/* rwsem.c: R/W semaphores: contention handling functions
- *
- * Written by David Howells (dhowells@redhat.com).
- * Derived from arch/i386/kernel/semaphore.c
- *
- * Writer lock-stealing by Alex Shi <alex.shi@intel.com>
- * and Michel Lespinasse <walken@google.com>
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/export.h>
-
-/*
- * Initialize an rwsem:
- */
-void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held semaphore:
- */
- debug_check_no_locks_freed((void *)sem, sizeof(*sem));
- lockdep_init_map(&sem->dep_map, name, key, 0);
-#endif
- sem->count = RWSEM_UNLOCKED_VALUE;
- raw_spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-EXPORT_SYMBOL(__init_rwsem);
-
-enum rwsem_waiter_type {
- RWSEM_WAITING_FOR_WRITE,
- RWSEM_WAITING_FOR_READ
-};
-
-struct rwsem_waiter {
- struct list_head list;
- struct task_struct *task;
- enum rwsem_waiter_type type;
-};
-
-enum rwsem_wake_type {
- RWSEM_WAKE_ANY, /* Wake whatever's at head of wait list */
- RWSEM_WAKE_READERS, /* Wake readers only */
- RWSEM_WAKE_READ_OWNED /* Waker thread holds the read lock */
-};
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here from up_xxxx(), then:
- * - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed)
- * - the 'waiting part' of count (&0xffff0000) is -ve (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 task zeroed
- * - writers are only woken if downgrading is false
- */
-static struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type)
-{
- struct rwsem_waiter *waiter;
- struct task_struct *tsk;
- struct list_head *next;
- long oldcount, woken, loop, adjustment;
-
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
- if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
- if (wake_type == RWSEM_WAKE_ANY)
- /* Wake writer at the front of the queue, but do not
- * grant it the lock yet as we want other writers
- * to be able to steal it. Readers, on the other hand,
- * will block as they will notice the queued writer.
- */
- wake_up_process(waiter->task);
- goto out;
- }
-
- /* Writers might steal the lock before we grant it to the next reader.
- * We prefer to do the first reader grant before counting readers
- * so we can bail out early if a writer stole the lock.
- */
- adjustment = 0;
- if (wake_type != RWSEM_WAKE_READ_OWNED) {
- adjustment = RWSEM_ACTIVE_READ_BIAS;
- try_reader_grant:
- oldcount = rwsem_atomic_update(adjustment, sem) - adjustment;
- if (unlikely(oldcount < RWSEM_WAITING_BIAS)) {
- /* A writer stole the lock. Undo our reader grant. */
- if (rwsem_atomic_update(-adjustment, sem) &
- RWSEM_ACTIVE_MASK)
- goto out;
- /* Last active locker left. Retry waking readers. */
- goto try_reader_grant;
- }
- }
-
- /* 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 before waking any processes up.
- */
- woken = 0;
- do {
- woken++;
-
- if (waiter->list.next == &sem->wait_list)
- break;
-
- waiter = list_entry(waiter->list.next,
- struct rwsem_waiter, list);
-
- } while (waiter->type != RWSEM_WAITING_FOR_WRITE);
-
- adjustment = woken * RWSEM_ACTIVE_READ_BIAS - adjustment;
- if (waiter->type != RWSEM_WAITING_FOR_WRITE)
- /* hit end of list above */
- adjustment -= RWSEM_WAITING_BIAS;
-
- if (adjustment)
- rwsem_atomic_add(adjustment, sem);
-
- next = sem->wait_list.next;
- loop = woken;
- do {
- waiter = list_entry(next, struct rwsem_waiter, list);
- next = waiter->list.next;
- tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- } while (--loop);
-
- sem->wait_list.next = next;
- next->prev = &sem->wait_list;
-
- out:
- return sem;
-}
-
-/*
- * wait for the read lock to be granted
- */
-struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
-{
- long count, adjustment = -RWSEM_ACTIVE_READ_BIAS;
- struct rwsem_waiter waiter;
- struct task_struct *tsk = current;
-
- /* set up my own style of waitqueue */
- waiter.task = tsk;
- waiter.type = RWSEM_WAITING_FOR_READ;
- get_task_struct(tsk);
-
- raw_spin_lock_irq(&sem->wait_lock);
- if (list_empty(&sem->wait_list))
- adjustment += RWSEM_WAITING_BIAS;
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we're now waiting on the lock, but no longer actively locking */
- count = rwsem_atomic_update(adjustment, sem);
-
- /* If there are no active locks, wake the front queued process(es).
- *
- * If there are no writers and we are first in the queue,
- * wake our own waiter to join the existing active readers !
- */
- if (count == RWSEM_WAITING_BIAS ||
- (count > RWSEM_WAITING_BIAS &&
- adjustment != -RWSEM_ACTIVE_READ_BIAS))
- sem = __rwsem_do_wake(sem, RWSEM_WAKE_ANY);
-
- raw_spin_unlock_irq(&sem->wait_lock);
-
- /* wait to be given the lock */
- while (true) {
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- if (!waiter.task)
- break;
- schedule();
- }
-
- tsk->state = TASK_RUNNING;
-
- return sem;
-}
-
-/*
- * wait until we successfully acquire the write lock
- */
-struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
-{
- long count, adjustment = -RWSEM_ACTIVE_WRITE_BIAS;
- struct rwsem_waiter waiter;
- struct task_struct *tsk = current;
-
- /* set up my own style of waitqueue */
- waiter.task = tsk;
- waiter.type = RWSEM_WAITING_FOR_WRITE;
-
- raw_spin_lock_irq(&sem->wait_lock);
- if (list_empty(&sem->wait_list))
- adjustment += RWSEM_WAITING_BIAS;
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we're now waiting on the lock, but no longer actively locking */
- count = rwsem_atomic_update(adjustment, sem);
-
- /* If there were already threads queued before us and there are no
- * active writers, the lock must be read owned; so we try to wake
- * any read locks that were queued ahead of us. */
- if (count > RWSEM_WAITING_BIAS &&
- adjustment == -RWSEM_ACTIVE_WRITE_BIAS)
- sem = __rwsem_do_wake(sem, RWSEM_WAKE_READERS);
-
- /* wait until we successfully acquire the lock */
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- while (true) {
- if (!(count & RWSEM_ACTIVE_MASK)) {
- /* Try acquiring the write lock. */
- count = RWSEM_ACTIVE_WRITE_BIAS;
- if (!list_is_singular(&sem->wait_list))
- count += RWSEM_WAITING_BIAS;
-
- if (sem->count == RWSEM_WAITING_BIAS &&
- cmpxchg(&sem->count, RWSEM_WAITING_BIAS, count) ==
- RWSEM_WAITING_BIAS)
- break;
- }
-
- raw_spin_unlock_irq(&sem->wait_lock);
-
- /* Block until there are no active lockers. */
- do {
- schedule();
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- } while ((count = sem->count) & RWSEM_ACTIVE_MASK);
-
- raw_spin_lock_irq(&sem->wait_lock);
- }
-
- list_del(&waiter.list);
- raw_spin_unlock_irq(&sem->wait_lock);
- tsk->state = TASK_RUNNING;
-
- return sem;
-}
-
-/*
- * handle waking up a waiter on the semaphore
- * - up_read/up_write has decremented the active part of count if we come here
- */
-struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- /* do nothing if list empty */
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, RWSEM_WAKE_ANY);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return sem;
-}
-
-/*
- * downgrade a write lock into a read lock
- * - caller incremented waiting part of count and discovered it still negative
- * - just wake up any readers at the front of the queue
- */
-struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- /* do nothing if list empty */
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, RWSEM_WAKE_READ_OWNED);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return sem;
-}
-
-EXPORT_SYMBOL(rwsem_down_read_failed);
-EXPORT_SYMBOL(rwsem_down_write_failed);
-EXPORT_SYMBOL(rwsem_wake);
-EXPORT_SYMBOL(rwsem_downgrade_wake);
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
deleted file mode 100644
index 0374a59..0000000
--- a/lib/spinlock_debug.c
+++ /dev/null
@@ -1,302 +0,0 @@
-/*
- * Copyright 2005, Red Hat, Inc., Ingo Molnar
- * Released under the General Public License (GPL).
- *
- * This file contains the spinlock/rwlock implementations for
- * DEBUG_SPINLOCK.
- */
-
-#include <linux/spinlock.h>
-#include <linux/nmi.h>
-#include <linux/interrupt.h>
-#include <linux/debug_locks.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-
-void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held lock:
- */
- debug_check_no_locks_freed((void *)lock, sizeof(*lock));
- lockdep_init_map(&lock->dep_map, name, key, 0);
-#endif
- lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
- lock->magic = SPINLOCK_MAGIC;
- lock->owner = SPINLOCK_OWNER_INIT;
- lock->owner_cpu = -1;
-}
-
-EXPORT_SYMBOL(__raw_spin_lock_init);
-
-void __rwlock_init(rwlock_t *lock, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held lock:
- */
- debug_check_no_locks_freed((void *)lock, sizeof(*lock));
- lockdep_init_map(&lock->dep_map, name, key, 0);
-#endif
- lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
- lock->magic = RWLOCK_MAGIC;
- lock->owner = SPINLOCK_OWNER_INIT;
- lock->owner_cpu = -1;
-}
-
-EXPORT_SYMBOL(__rwlock_init);
-
-static void spin_dump(raw_spinlock_t *lock, const char *msg)
-{
- struct task_struct *owner = NULL;
-
- if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
- owner = lock->owner;
- printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
- msg, raw_smp_processor_id(),
- current->comm, task_pid_nr(current));
- printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
- ".owner_cpu: %d\n",
- lock, lock->magic,
- owner ? owner->comm : "<none>",
- owner ? task_pid_nr(owner) : -1,
- lock->owner_cpu);
- dump_stack();
-}
-
-static void spin_bug(raw_spinlock_t *lock, const char *msg)
-{
- if (!debug_locks_off())
- return;
-
- spin_dump(lock, msg);
-}
-
-#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
-
-static inline void
-debug_spin_lock_before(raw_spinlock_t *lock)
-{
- SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
- SPIN_BUG_ON(lock->owner == current, lock, "recursion");
- SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
- lock, "cpu recursion");
-}
-
-static inline void debug_spin_lock_after(raw_spinlock_t *lock)
-{
- lock->owner_cpu = raw_smp_processor_id();
- lock->owner = current;
-}
-
-static inline void debug_spin_unlock(raw_spinlock_t *lock)
-{
- SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
- SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
- SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
- SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
- lock, "wrong CPU");
- lock->owner = SPINLOCK_OWNER_INIT;
- lock->owner_cpu = -1;
-}
-
-static void __spin_lock_debug(raw_spinlock_t *lock)
-{
- u64 i;
- u64 loops = loops_per_jiffy * HZ;
-
- for (i = 0; i < loops; i++) {
- if (arch_spin_trylock(&lock->raw_lock))
- return;
- __delay(1);
- }
- /* lockup suspected: */
- spin_dump(lock, "lockup suspected");
-#ifdef CONFIG_SMP
- trigger_all_cpu_backtrace();
-#endif
-
- /*
- * The trylock above was causing a livelock. Give the lower level arch
- * specific lock code a chance to acquire the lock. We have already
- * printed a warning/backtrace at this point. The non-debug arch
- * specific code might actually succeed in acquiring the lock. If it is
- * not successful, the end-result is the same - there is no forward
- * progress.
- */
- arch_spin_lock(&lock->raw_lock);
-}
-
-void do_raw_spin_lock(raw_spinlock_t *lock)
-{
- debug_spin_lock_before(lock);
- if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
- __spin_lock_debug(lock);
- debug_spin_lock_after(lock);
-}
-
-int do_raw_spin_trylock(raw_spinlock_t *lock)
-{
- int ret = arch_spin_trylock(&lock->raw_lock);
-
- if (ret)
- debug_spin_lock_after(lock);
-#ifndef CONFIG_SMP
- /*
- * Must not happen on UP:
- */
- SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
-#endif
- return ret;
-}
-
-void do_raw_spin_unlock(raw_spinlock_t *lock)
-{
- debug_spin_unlock(lock);
- arch_spin_unlock(&lock->raw_lock);
-}
-
-static void rwlock_bug(rwlock_t *lock, const char *msg)
-{
- if (!debug_locks_off())
- return;
-
- printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
- msg, raw_smp_processor_id(), current->comm,
- task_pid_nr(current), lock);
- dump_stack();
-}
-
-#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
-
-#if 0 /* __write_lock_debug() can lock up - maybe this can too? */
-static void __read_lock_debug(rwlock_t *lock)
-{
- u64 i;
- u64 loops = loops_per_jiffy * HZ;
- int print_once = 1;
-
- for (;;) {
- for (i = 0; i < loops; i++) {
- if (arch_read_trylock(&lock->raw_lock))
- return;
- __delay(1);
- }
- /* lockup suspected: */
- if (print_once) {
- print_once = 0;
- printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
- "%s/%d, %p\n",
- raw_smp_processor_id(), current->comm,
- current->pid, lock);
- dump_stack();
- }
- }
-}
-#endif
-
-void do_raw_read_lock(rwlock_t *lock)
-{
- RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
- arch_read_lock(&lock->raw_lock);
-}
-
-int do_raw_read_trylock(rwlock_t *lock)
-{
- int ret = arch_read_trylock(&lock->raw_lock);
-
-#ifndef CONFIG_SMP
- /*
- * Must not happen on UP:
- */
- RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
-#endif
- return ret;
-}
-
-void do_raw_read_unlock(rwlock_t *lock)
-{
- RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
- arch_read_unlock(&lock->raw_lock);
-}
-
-static inline void debug_write_lock_before(rwlock_t *lock)
-{
- RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
- RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
- RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
- lock, "cpu recursion");
-}
-
-static inline void debug_write_lock_after(rwlock_t *lock)
-{
- lock->owner_cpu = raw_smp_processor_id();
- lock->owner = current;
-}
-
-static inline void debug_write_unlock(rwlock_t *lock)
-{
- RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
- RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
- RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
- lock, "wrong CPU");
- lock->owner = SPINLOCK_OWNER_INIT;
- lock->owner_cpu = -1;
-}
-
-#if 0 /* This can cause lockups */
-static void __write_lock_debug(rwlock_t *lock)
-{
- u64 i;
- u64 loops = loops_per_jiffy * HZ;
- int print_once = 1;
-
- for (;;) {
- for (i = 0; i < loops; i++) {
- if (arch_write_trylock(&lock->raw_lock))
- return;
- __delay(1);
- }
- /* lockup suspected: */
- if (print_once) {
- print_once = 0;
- printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
- "%s/%d, %p\n",
- raw_smp_processor_id(), current->comm,
- current->pid, lock);
- dump_stack();
- }
- }
-}
-#endif
-
-void do_raw_write_lock(rwlock_t *lock)
-{
- debug_write_lock_before(lock);
- arch_write_lock(&lock->raw_lock);
- debug_write_lock_after(lock);
-}
-
-int do_raw_write_trylock(rwlock_t *lock)
-{
- int ret = arch_write_trylock(&lock->raw_lock);
-
- if (ret)
- debug_write_lock_after(lock);
-#ifndef CONFIG_SMP
- /*
- * Must not happen on UP:
- */
- RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
-#endif
- return ret;
-}
-
-void do_raw_write_unlock(rwlock_t *lock)
-{
- debug_write_unlock(lock);
- arch_write_unlock(&lock->raw_lock);
-}
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