Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 303 insertions, 0 deletions

diff --git a/drivers/char/drm/drm_lock.c b/drivers/char/drm/drm_lock.c
new file mode 100644
index 00000000000..d0d6fc66162
--- /dev/null
+++ b/drivers/char/drm/drm_lock.c
@@ -0,0 +1,303 @@
+/**
+ * \file drm_lock.h 
+ * IOCTLs for locking
+ * 
+ * \author Rickard E. (Rik) Faith <faith@valinux.com>
+ * \author Gareth Hughes <gareth@valinux.com>
+ */
+
+/*
+ * 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.
+ */
+
+#include "drmP.h"
+
+/** 
+ * Lock ioctl.
+ *
+ * \param inode device inode.
+ * \param filp file pointer.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_lock structure.
+ * \return zero on success or negative number on failure.
+ *
+ * Add the current task to the lock wait queue, and attempt to take to lock.
+ */
+int drm_lock( struct inode *inode, struct file *filp,
+	       unsigned int cmd, unsigned long arg )
+{
+        drm_file_t *priv = filp->private_data;
+        drm_device_t *dev = priv->head->dev;
+        DECLARE_WAITQUEUE( entry, current );
+        drm_lock_t lock;
+        int ret = 0;
+
+	++priv->lock_count;
+
+        if ( copy_from_user( &lock, (drm_lock_t __user *)arg, sizeof(lock) ) )
+		return -EFAULT;
+
+        if ( lock.context == DRM_KERNEL_CONTEXT ) {
+                DRM_ERROR( "Process %d using kernel context %d\n",
+			   current->pid, lock.context );
+                return -EINVAL;
+        }
+
+        DRM_DEBUG( "%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
+		   lock.context, current->pid,
+		   dev->lock.hw_lock->lock, lock.flags );
+
+	if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
+		if ( lock.context < 0 )
+			return -EINVAL;
+
+	add_wait_queue( &dev->lock.lock_queue, &entry );
+	for (;;) {
+		__set_current_state(TASK_INTERRUPTIBLE);
+		if ( !dev->lock.hw_lock ) {
+			/* Device has been unregistered */
+			ret = -EINTR;
+			break;
+		}
+		if ( drm_lock_take( &dev->lock.hw_lock->lock,
+				     lock.context ) ) {
+			dev->lock.filp      = filp;
+			dev->lock.lock_time = jiffies;
+			atomic_inc( &dev->counts[_DRM_STAT_LOCKS] );
+			break;  /* Got lock */
+		}
+		
+		/* Contention */
+		schedule();
+		if ( signal_pending( current ) ) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+	}
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue( &dev->lock.lock_queue, &entry );
+
+	sigemptyset( &dev->sigmask );
+	sigaddset( &dev->sigmask, SIGSTOP );
+	sigaddset( &dev->sigmask, SIGTSTP );
+	sigaddset( &dev->sigmask, SIGTTIN );
+	sigaddset( &dev->sigmask, SIGTTOU );
+	dev->sigdata.context = lock.context;
+	dev->sigdata.lock    = dev->lock.hw_lock;
+	block_all_signals( drm_notifier,
+			   &dev->sigdata, &dev->sigmask );
+	
+	if (dev->driver->dma_ready && (lock.flags & _DRM_LOCK_READY))
+		dev->driver->dma_ready(dev);
+	
+	if ( dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT ))
+		return dev->driver->dma_quiescent(dev);
+	
+	/* dev->driver->kernel_context_switch isn't used by any of the x86 
+	 *  drivers but is used by the Sparc driver.
+	 */
+	
+	if (dev->driver->kernel_context_switch && 
+	    dev->last_context != lock.context) {
+	  dev->driver->kernel_context_switch(dev, dev->last_context, 
+					    lock.context);
+	}
+        DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" );
+
+        return ret;
+}
+
+/** 
+ * Unlock ioctl.
+ *
+ * \param inode device inode.
+ * \param filp file pointer.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_lock structure.
+ * \return zero on success or negative number on failure.
+ *
+ * Transfer and free the lock.
+ */
+int drm_unlock( struct inode *inode, struct file *filp,
+		 unsigned int cmd, unsigned long arg )
+{
+	drm_file_t *priv = filp->private_data;
+	drm_device_t *dev = priv->head->dev;
+	drm_lock_t lock;
+
+	if ( copy_from_user( &lock, (drm_lock_t __user *)arg, sizeof(lock) ) )
+		return -EFAULT;
+
+	if ( lock.context == DRM_KERNEL_CONTEXT ) {
+		DRM_ERROR( "Process %d using kernel context %d\n",
+			   current->pid, lock.context );
+		return -EINVAL;
+	}
+
+	atomic_inc( &dev->counts[_DRM_STAT_UNLOCKS] );
+
+	/* kernel_context_switch isn't used by any of the x86 drm
+	 * modules but is required by the Sparc driver.
+	 */
+	if (dev->driver->kernel_context_switch_unlock)
+		dev->driver->kernel_context_switch_unlock(dev, &lock);
+	else {
+		drm_lock_transfer( dev, &dev->lock.hw_lock->lock, 
+				    DRM_KERNEL_CONTEXT );
+		
+		if ( drm_lock_free( dev, &dev->lock.hw_lock->lock,
+				     DRM_KERNEL_CONTEXT ) ) {
+			DRM_ERROR( "\n" );
+		}
+	}
+
+	unblock_all_signals();
+	return 0;
+}
+
+/**
+ * Take the heavyweight lock.
+ *
+ * \param lock lock pointer.
+ * \param context locking context.
+ * \return one if the lock is held, or zero otherwise.
+ *
+ * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
+ */
+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. 
+ * 
+ * \param dev DRM device.
+ * \param lock lock pointer.
+ * \param context locking context.
+ * \return always one.
+ *
+ * Resets the lock file pointer.
+ * Marks the lock as held by the given context, via the \p cmpxchg instruction.
+ */
+int drm_lock_transfer(drm_device_t *dev,
+		       __volatile__ unsigned int *lock, unsigned int context)
+{
+	unsigned int old, new, prev;
+
+	dev->lock.filp = NULL;
+	do {
+		old  = *lock;
+		new  = context | _DRM_LOCK_HELD;
+		prev = cmpxchg(lock, old, new);
+	} while (prev != old);
+	return 1;
+}
+
+/**
+ * Free lock.
+ * 
+ * \param dev DRM device.
+ * \param lock lock.
+ * \param context context.
+ * 
+ * Resets the lock file pointer.
+ * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
+ * waiting on the lock queue.
+ */
+int drm_lock_free(drm_device_t *dev,
+		   __volatile__ unsigned int *lock, unsigned int context)
+{
+	unsigned int old, new, prev;
+
+	dev->lock.filp = NULL;
+	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\n",
+			  context,
+			  _DRM_LOCKING_CONTEXT(old));
+		return 1;
+	}
+	wake_up_interruptible(&dev->lock.lock_queue);
+	return 0;
+}
+
+/**
+ * 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.
+ *
+ * \param priv pointer to a drm_sigdata structure.
+ * \return one if the signal should be delivered normally, or zero 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 (!s->lock || !_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;
+}