patch-2.4.8 linux/drivers/char/drm/drm_lock.h

• Lines: 252
• Date: Fri Aug 10 18:14:41 2001
• Orig file: v2.4.7/linux/drivers/char/drm/drm_lock.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.7/linux/drivers/char/drm/drm_lock.h linux/drivers/char/drm/drm_lock.h
@@ -0,0 +1,251 @@
+/* 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;
+}