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-rw-r--r--linux-core/drm_lock.c251
1 files changed, 251 insertions, 0 deletions
diff --git a/linux-core/drm_lock.c b/linux-core/drm_lock.c
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+++ b/linux-core/drm_lock.c
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+/* lock.c -- IOCTLs for locking -*- linux-c -*-
+ * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
+ *
+ * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
+ * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
+ * 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, sublicense,
+ * 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 NONINFRINGEMENT. IN NO EVENT SHALL
+ * VA LINUX SYSTEMS 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:
+ * Rickard E. (Rik) Faith <faith@valinux.com>
+ * Gareth Hughes <gareth@valinux.com>
+ */
+
+#define __NO_VERSION__
+#include "drmP.h"
+
+int DRM(block)(struct inode *inode, struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ DRM_DEBUG("\n");
+ return 0;
+}
+
+int DRM(unblock)(struct inode *inode, struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ DRM_DEBUG("\n");
+ return 0;
+}
+
+int DRM(lock_take)(__volatile__ unsigned int *lock, unsigned int context)
+{
+ unsigned int old, new, prev;
+
+ do {
+ old = *lock;
+ if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT;
+ else new = context | _DRM_LOCK_HELD;
+ prev = cmpxchg(lock, old, new);
+ } while (prev != old);
+ if (_DRM_LOCKING_CONTEXT(old) == context) {
+ if (old & _DRM_LOCK_HELD) {
+ if (context != DRM_KERNEL_CONTEXT) {
+ DRM_ERROR("%d holds heavyweight lock\n",
+ context);
+ }
+ return 0;
+ }
+ }
+ if (new == (context | _DRM_LOCK_HELD)) {
+ /* Have lock */
+ return 1;
+ }
+ return 0;
+}
+
+/* This takes a lock forcibly and hands it to context. Should ONLY be used
+ inside *_unlock to give lock to kernel before calling *_dma_schedule. */
+int DRM(lock_transfer)(drm_device_t *dev,
+ __volatile__ unsigned int *lock, unsigned int context)
+{
+ unsigned int old, new, prev;
+
+ dev->lock.pid = 0;
+ do {
+ old = *lock;
+ new = context | _DRM_LOCK_HELD;
+ prev = cmpxchg(lock, old, new);
+ } while (prev != old);
+ return 1;
+}
+
+int DRM(lock_free)(drm_device_t *dev,
+ __volatile__ unsigned int *lock, unsigned int context)
+{
+ unsigned int old, new, prev;
+ pid_t pid = dev->lock.pid;
+
+ dev->lock.pid = 0;
+ do {
+ old = *lock;
+ new = 0;
+ prev = cmpxchg(lock, old, new);
+ } while (prev != old);
+ if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
+ DRM_ERROR("%d freed heavyweight lock held by %d (pid %d)\n",
+ context,
+ _DRM_LOCKING_CONTEXT(old),
+ pid);
+ return 1;
+ }
+ wake_up_interruptible(&dev->lock.lock_queue);
+ return 0;
+}
+
+static int DRM(flush_queue)(drm_device_t *dev, int context)
+{
+ DECLARE_WAITQUEUE(entry, current);
+ int ret = 0;
+ drm_queue_t *q = dev->queuelist[context];
+
+ DRM_DEBUG("\n");
+
+ atomic_inc(&q->use_count);
+ if (atomic_read(&q->use_count) > 1) {
+ atomic_inc(&q->block_write);
+ add_wait_queue(&q->flush_queue, &entry);
+ atomic_inc(&q->block_count);
+ for (;;) {
+ current->state = TASK_INTERRUPTIBLE;
+ if (!DRM_BUFCOUNT(&q->waitlist)) break;
+ schedule();
+ if (signal_pending(current)) {
+ ret = -EINTR; /* Can't restart */
+ break;
+ }
+ }
+ atomic_dec(&q->block_count);
+ current->state = TASK_RUNNING;
+ remove_wait_queue(&q->flush_queue, &entry);
+ }
+ atomic_dec(&q->use_count);
+
+ /* NOTE: block_write is still incremented!
+ Use drm_flush_unlock_queue to decrement. */
+ return ret;
+}
+
+static int DRM(flush_unblock_queue)(drm_device_t *dev, int context)
+{
+ drm_queue_t *q = dev->queuelist[context];
+
+ DRM_DEBUG("\n");
+
+ atomic_inc(&q->use_count);
+ if (atomic_read(&q->use_count) > 1) {
+ if (atomic_read(&q->block_write)) {
+ atomic_dec(&q->block_write);
+ wake_up_interruptible(&q->write_queue);
+ }
+ }
+ atomic_dec(&q->use_count);
+ return 0;
+}
+
+int DRM(flush_block_and_flush)(drm_device_t *dev, int context,
+ drm_lock_flags_t flags)
+{
+ int ret = 0;
+ int i;
+
+ DRM_DEBUG("\n");
+
+ if (flags & _DRM_LOCK_FLUSH) {
+ ret = DRM(flush_queue)(dev, DRM_KERNEL_CONTEXT);
+ if (!ret) ret = DRM(flush_queue)(dev, context);
+ }
+ if (flags & _DRM_LOCK_FLUSH_ALL) {
+ for (i = 0; !ret && i < dev->queue_count; i++) {
+ ret = DRM(flush_queue)(dev, i);
+ }
+ }
+ return ret;
+}
+
+int DRM(flush_unblock)(drm_device_t *dev, int context, drm_lock_flags_t flags)
+{
+ int ret = 0;
+ int i;
+
+ DRM_DEBUG("\n");
+
+ if (flags & _DRM_LOCK_FLUSH) {
+ ret = DRM(flush_unblock_queue)(dev, DRM_KERNEL_CONTEXT);
+ if (!ret) ret = DRM(flush_unblock_queue)(dev, context);
+ }
+ if (flags & _DRM_LOCK_FLUSH_ALL) {
+ for (i = 0; !ret && i < dev->queue_count; i++) {
+ ret = DRM(flush_unblock_queue)(dev, i);
+ }
+ }
+
+ return ret;
+}
+
+int DRM(finish)(struct inode *inode, struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ drm_file_t *priv = filp->private_data;
+ drm_device_t *dev = priv->dev;
+ int ret = 0;
+ drm_lock_t lock;
+
+ DRM_DEBUG("\n");
+
+ if (copy_from_user(&lock, (drm_lock_t *)arg, sizeof(lock)))
+ return -EFAULT;
+ ret = DRM(flush_block_and_flush)(dev, lock.context, lock.flags);
+ DRM(flush_unblock)(dev, lock.context, lock.flags);
+ return ret;
+}
+
+/* If we get here, it means that the process has called DRM_IOCTL_LOCK
+ without calling DRM_IOCTL_UNLOCK.
+
+ If the lock is not held, then let the signal proceed as usual.
+
+ If the lock is held, then set the contended flag and keep the signal
+ blocked.
+
+
+ Return 1 if the signal should be delivered normally.
+ Return 0 if the signal should be blocked. */
+
+int DRM(notifier)(void *priv)
+{
+ drm_sigdata_t *s = (drm_sigdata_t *)priv;
+ unsigned int old, new, prev;
+
+
+ /* Allow signal delivery if lock isn't held */
+ if (!_DRM_LOCK_IS_HELD(s->lock->lock)
+ || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) return 1;
+
+ /* Otherwise, set flag to force call to
+ drmUnlock */
+ do {
+ old = s->lock->lock;
+ new = old | _DRM_LOCK_CONT;
+ prev = cmpxchg(&s->lock->lock, old, new);
+ } while (prev != old);
+ return 0;
+}