--- /dev/null
+/**************************************************************************
+ *
+ * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+/*
+ * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
+ */
+
+#include <drm/ttm/ttm_lock.h>
+#include <drm/ttm/ttm_module.h>
+#include <linux/atomic.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+
+#define TTM_WRITE_LOCK_PENDING (1 << 0)
+#define TTM_VT_LOCK_PENDING (1 << 1)
+#define TTM_SUSPEND_LOCK_PENDING (1 << 2)
+#define TTM_VT_LOCK (1 << 3)
+#define TTM_SUSPEND_LOCK (1 << 4)
+
+void ttm_lock_init(struct ttm_lock *lock)
+{
+ spin_lock_init(&lock->lock);
+ init_waitqueue_head(&lock->queue);
+ lock->rw = 0;
+ lock->flags = 0;
+ lock->kill_takers = false;
+ lock->signal = SIGKILL;
+}
+EXPORT_SYMBOL(ttm_lock_init);
+
+void ttm_read_unlock(struct ttm_lock *lock)
+{
+ spin_lock(&lock->lock);
+ if (--lock->rw == 0)
+ wake_up_all(&lock->queue);
+ spin_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(ttm_read_unlock);
+
+static bool __ttm_read_lock(struct ttm_lock *lock)
+{
+ bool locked = false;
+
+ spin_lock(&lock->lock);
+ if (unlikely(lock->kill_takers)) {
+ send_sig(lock->signal, current, 0);
+ spin_unlock(&lock->lock);
+ return false;
+ }
+ if (lock->rw >= 0 && lock->flags == 0) {
+ ++lock->rw;
+ locked = true;
+ }
+ spin_unlock(&lock->lock);
+ return locked;
+}
+
+int ttm_read_lock(struct ttm_lock *lock, bool interruptible)
+{
+ int ret = 0;
+
+ if (interruptible)
+ ret = wait_event_interruptible(lock->queue,
+ __ttm_read_lock(lock));
+ else
+ wait_event(lock->queue, __ttm_read_lock(lock));
+ return ret;
+}
+EXPORT_SYMBOL(ttm_read_lock);
+
+static bool __ttm_read_trylock(struct ttm_lock *lock, bool *locked)
+{
+ bool block = true;
+
+ *locked = false;
+
+ spin_lock(&lock->lock);
+ if (unlikely(lock->kill_takers)) {
+ send_sig(lock->signal, current, 0);
+ spin_unlock(&lock->lock);
+ return false;
+ }
+ if (lock->rw >= 0 && lock->flags == 0) {
+ ++lock->rw;
+ block = false;
+ *locked = true;
+ } else if (lock->flags == 0) {
+ block = false;
+ }
+ spin_unlock(&lock->lock);
+
+ return !block;
+}
+
+int ttm_read_trylock(struct ttm_lock *lock, bool interruptible)
+{
+ int ret = 0;
+ bool locked;
+
+ if (interruptible)
+ ret = wait_event_interruptible
+ (lock->queue, __ttm_read_trylock(lock, &locked));
+ else
+ wait_event(lock->queue, __ttm_read_trylock(lock, &locked));
+
+ if (unlikely(ret != 0)) {
+ BUG_ON(locked);
+ return ret;
+ }
+
+ return (locked) ? 0 : -EBUSY;
+}
+
+void ttm_write_unlock(struct ttm_lock *lock)
+{
+ spin_lock(&lock->lock);
+ lock->rw = 0;
+ wake_up_all(&lock->queue);
+ spin_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(ttm_write_unlock);
+
+static bool __ttm_write_lock(struct ttm_lock *lock)
+{
+ bool locked = false;
+
+ spin_lock(&lock->lock);
+ if (unlikely(lock->kill_takers)) {
+ send_sig(lock->signal, current, 0);
+ spin_unlock(&lock->lock);
+ return false;
+ }
+ if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) {
+ lock->rw = -1;
+ lock->flags &= ~TTM_WRITE_LOCK_PENDING;
+ locked = true;
+ } else {
+ lock->flags |= TTM_WRITE_LOCK_PENDING;
+ }
+ spin_unlock(&lock->lock);
+ return locked;
+}
+
+int ttm_write_lock(struct ttm_lock *lock, bool interruptible)
+{
+ int ret = 0;
+
+ if (interruptible) {
+ ret = wait_event_interruptible(lock->queue,
+ __ttm_write_lock(lock));
+ if (unlikely(ret != 0)) {
+ spin_lock(&lock->lock);
+ lock->flags &= ~TTM_WRITE_LOCK_PENDING;
+ wake_up_all(&lock->queue);
+ spin_unlock(&lock->lock);
+ }
+ } else
+ wait_event(lock->queue, __ttm_read_lock(lock));
+
+ return ret;
+}
+EXPORT_SYMBOL(ttm_write_lock);
+
+static int __ttm_vt_unlock(struct ttm_lock *lock)
+{
+ int ret = 0;
+
+ spin_lock(&lock->lock);
+ if (unlikely(!(lock->flags & TTM_VT_LOCK)))
+ ret = -EINVAL;
+ lock->flags &= ~TTM_VT_LOCK;
+ wake_up_all(&lock->queue);
+ spin_unlock(&lock->lock);
+
+ return ret;
+}
+
+static void ttm_vt_lock_remove(struct ttm_base_object **p_base)
+{
+ struct ttm_base_object *base = *p_base;
+ struct ttm_lock *lock = container_of(base, struct ttm_lock, base);
+ int ret;
+
+ *p_base = NULL;
+ ret = __ttm_vt_unlock(lock);
+ BUG_ON(ret != 0);
+}
+
+static bool __ttm_vt_lock(struct ttm_lock *lock)
+{
+ bool locked = false;
+
+ spin_lock(&lock->lock);
+ if (lock->rw == 0) {
+ lock->flags &= ~TTM_VT_LOCK_PENDING;
+ lock->flags |= TTM_VT_LOCK;
+ locked = true;
+ } else {
+ lock->flags |= TTM_VT_LOCK_PENDING;
+ }
+ spin_unlock(&lock->lock);
+ return locked;
+}
+
+int ttm_vt_lock(struct ttm_lock *lock,
+ bool interruptible,
+ struct ttm_object_file *tfile)
+{
+ int ret = 0;
+
+ if (interruptible) {
+ ret = wait_event_interruptible(lock->queue,
+ __ttm_vt_lock(lock));
+ if (unlikely(ret != 0)) {
+ spin_lock(&lock->lock);
+ lock->flags &= ~TTM_VT_LOCK_PENDING;
+ wake_up_all(&lock->queue);
+ spin_unlock(&lock->lock);
+ return ret;
+ }
+ } else
+ wait_event(lock->queue, __ttm_vt_lock(lock));
+
+ /*
+ * Add a base-object, the destructor of which will
+ * make sure the lock is released if the client dies
+ * while holding it.
+ */
+
+ ret = ttm_base_object_init(tfile, &lock->base, false,
+ ttm_lock_type, &ttm_vt_lock_remove, NULL);
+ if (ret)
+ (void)__ttm_vt_unlock(lock);
+ else
+ lock->vt_holder = tfile;
+
+ return ret;
+}
+EXPORT_SYMBOL(ttm_vt_lock);
+
+int ttm_vt_unlock(struct ttm_lock *lock)
+{
+ return ttm_ref_object_base_unref(lock->vt_holder,
+ lock->base.hash.key, TTM_REF_USAGE);
+}
+EXPORT_SYMBOL(ttm_vt_unlock);
+
+void ttm_suspend_unlock(struct ttm_lock *lock)
+{
+ spin_lock(&lock->lock);
+ lock->flags &= ~TTM_SUSPEND_LOCK;
+ wake_up_all(&lock->queue);
+ spin_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(ttm_suspend_unlock);
+
+static bool __ttm_suspend_lock(struct ttm_lock *lock)
+{
+ bool locked = false;
+
+ spin_lock(&lock->lock);
+ if (lock->rw == 0) {
+ lock->flags &= ~TTM_SUSPEND_LOCK_PENDING;
+ lock->flags |= TTM_SUSPEND_LOCK;
+ locked = true;
+ } else {
+ lock->flags |= TTM_SUSPEND_LOCK_PENDING;
+ }
+ spin_unlock(&lock->lock);
+ return locked;
+}
+
+void ttm_suspend_lock(struct ttm_lock *lock)
+{
+ wait_event(lock->queue, __ttm_suspend_lock(lock));
+}
+EXPORT_SYMBOL(ttm_suspend_lock);
Code Review / kvmfornfv.git / blobdiff