drivers/gpu/drm/drm_fops.c - linux - Git at Google

 /**
  * \file drm_fops.c
  * File operations for DRM
  *
  * \author Rickard E. (Rik) Faith <faith@valinux.com>
  * \author Daryll Strauss <daryll@valinux.com>
  * \author Gareth Hughes <gareth@valinux.com>
  */

 /*
  * Created: Mon Jan  4 08:58:31 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 <drm/drmP.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
 #include <linux/module.h>

 /* from BKL pushdown: note that nothing else serializes idr_find() */
 DEFINE_MUTEX(drm_global_mutex);
 EXPORT_SYMBOL(drm_global_mutex);

 static int drm_open_helper(struct inode *inode, struct file *filp,
 			   struct drm_device * dev);

 static int drm_setup(struct drm_device * dev)
 {
 	int i;
 	int ret;

 	if (dev->driver->firstopen) {
 		ret = dev->driver->firstopen(dev);
 		if (ret != 0)
 			return ret;
 	}

 	atomic_set(&dev->ioctl_count, 0);
 	atomic_set(&dev->vma_count, 0);

 	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
 	    !drm_core_check_feature(dev, DRIVER_MODESET)) {
 		dev->buf_use = 0;
 		atomic_set(&dev->buf_alloc, 0);

 		i = drm_dma_setup(dev);
 		if (i < 0)
 			return i;
 	}

 	for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
 		atomic_set(&dev->counts[i], 0);

 	dev->sigdata.lock = NULL;

 	dev->context_flag = 0;
 	dev->interrupt_flag = 0;
 	dev->dma_flag = 0;
 	dev->last_context = 0;
 	dev->last_switch = 0;
 	dev->last_checked = 0;
 	init_waitqueue_head(&dev->context_wait);
 	dev->if_version = 0;

 	dev->ctx_start = 0;
 	dev->lck_start = 0;

 	dev->buf_async = NULL;
 	init_waitqueue_head(&dev->buf_readers);
 	init_waitqueue_head(&dev->buf_writers);

 	DRM_DEBUG("\n");

 	/*
 	 * The kernel's context could be created here, but is now created
 	 * in drm_dma_enqueue.  This is more resource-efficient for
 	 * hardware that does not do DMA, but may mean that
 	 * drm_select_queue fails between the time the interrupt is
 	 * initialized and the time the queues are initialized.
 	 */

 	return 0;
 }

 /**
  * Open file.
  *
  * \param inode device inode
  * \param filp file pointer.
  * \return zero on success or a negative number on failure.
  *
  * Searches the DRM device with the same minor number, calls open_helper(), and
  * increments the device open count. If the open count was previous at zero,
  * i.e., it's the first that the device is open, then calls setup().
  */
 int drm_open(struct inode *inode, struct file *filp)
 {
 	struct drm_device *dev = NULL;
 	int minor_id = iminor(inode);
 	struct drm_minor *minor;
 	int retcode = 0;
 	int need_setup = 0;
 	struct address_space *old_mapping;

 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (!minor)
 		return -ENODEV;

 	if (!(dev = minor->dev))
 		return -ENODEV;

 	if (drm_device_is_unplugged(dev))
 		return -ENODEV;

 	if (!dev->open_count++)
 		need_setup = 1;
 	mutex_lock(&dev->struct_mutex);
 	old_mapping = dev->dev_mapping;
 	if (old_mapping == NULL)
 		dev->dev_mapping = &inode->i_data;
 	/* ihold ensures nobody can remove inode with our i_data */
 	ihold(container_of(dev->dev_mapping, struct inode, i_data));
 	inode->i_mapping = dev->dev_mapping;
 	filp->f_mapping = dev->dev_mapping;
 	mutex_unlock(&dev->struct_mutex);

 	retcode = drm_open_helper(inode, filp, dev);
 	if (retcode)
 		goto err_undo;
 	atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
 	if (need_setup) {
 		retcode = drm_setup(dev);
 		if (retcode)
 			goto err_undo;
 	}
 	return 0;

 err_undo:
 	mutex_lock(&dev->struct_mutex);
 	filp->f_mapping = old_mapping;
 	inode->i_mapping = old_mapping;
 	iput(container_of(dev->dev_mapping, struct inode, i_data));
 	dev->dev_mapping = old_mapping;
 	mutex_unlock(&dev->struct_mutex);
 	dev->open_count--;
 	return retcode;
 }
 EXPORT_SYMBOL(drm_open);

 /**
  * File \c open operation.
  *
  * \param inode device inode.
  * \param filp file pointer.
  *
  * Puts the dev->fops corresponding to the device minor number into
  * \p filp, call the \c open method, and restore the file operations.
  */
 int drm_stub_open(struct inode *inode, struct file *filp)
 {
 	struct drm_device *dev = NULL;
 	struct drm_minor *minor;
 	int minor_id = iminor(inode);
 	int err = -ENODEV;
 	const struct file_operations *old_fops;

 	DRM_DEBUG("\n");

 	mutex_lock(&drm_global_mutex);
 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (!minor)
 		goto out;

 	if (!(dev = minor->dev))
 		goto out;

 	if (drm_device_is_unplugged(dev))
 		goto out;

 	old_fops = filp->f_op;
 	filp->f_op = fops_get(dev->driver->fops);
 	if (filp->f_op == NULL) {
 		filp->f_op = old_fops;
 		goto out;
 	}
 	if (filp->f_op->open && (err = filp->f_op->open(inode, filp))) {
 		fops_put(filp->f_op);
 		filp->f_op = fops_get(old_fops);
 	}
 	fops_put(old_fops);

 out:
 	mutex_unlock(&drm_global_mutex);
 	return err;
 }

 /**
  * Check whether DRI will run on this CPU.
  *
  * \return non-zero if the DRI will run on this CPU, or zero otherwise.
  */
 static int drm_cpu_valid(void)
 {
 #if defined(__i386__)
 	if (boot_cpu_data.x86 == 3)
 		return 0;	/* No cmpxchg on a 386 */
 #endif
 #if defined(__sparc__) && !defined(__sparc_v9__)
 	return 0;		/* No cmpxchg before v9 sparc. */
 #endif
 	return 1;
 }

 /**
  * Called whenever a process opens /dev/drm.
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param dev device.
  * \return zero on success or a negative number on failure.
  *
  * Creates and initializes a drm_file structure for the file private data in \p
  * filp and add it into the double linked list in \p dev.
  */
 static int drm_open_helper(struct inode *inode, struct file *filp,
 			   struct drm_device * dev)
 {
 	int minor_id = iminor(inode);
 	struct drm_file *priv;
 	int ret;

 	if (filp->f_flags & O_EXCL)
 		return -EBUSY;	/* No exclusive opens */
 	if (!drm_cpu_valid())
 		return -EINVAL;
 	if (dev->switch_power_state != DRM_SWITCH_POWER_ON)
 		return -EINVAL;

 	DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor_id);

 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	filp->private_data = priv;
 	priv->filp = filp;
 	priv->uid = current_euid();
 	priv->pid = get_pid(task_pid(current));
 	priv->minor = idr_find(&drm_minors_idr, minor_id);
 	priv->ioctl_count = 0;
 	/* for compatibility root is always authenticated */
 	priv->authenticated = capable(CAP_SYS_ADMIN);
 	priv->lock_count = 0;

 	INIT_LIST_HEAD(&priv->lhead);
 	INIT_LIST_HEAD(&priv->fbs);
 	INIT_LIST_HEAD(&priv->event_list);
 	init_waitqueue_head(&priv->event_wait);
 	priv->event_space = 4096; /* set aside 4k for event buffer */

 	if (dev->driver->driver_features & DRIVER_GEM)
 		drm_gem_open(dev, priv);

 	if (drm_core_check_feature(dev, DRIVER_PRIME))
 		drm_prime_init_file_private(&priv->prime);

 	if (dev->driver->open) {
 		ret = dev->driver->open(dev, priv);
 		if (ret < 0)
 			goto out_free;
 	}


 	/* if there is no current master make this fd it */
 	mutex_lock(&dev->struct_mutex);
 	if (!priv->minor->master) {
 		/* create a new master */
 		priv->minor->master = drm_master_create(priv->minor);
 		if (!priv->minor->master) {
 			mutex_unlock(&dev->struct_mutex);
 			ret = -ENOMEM;
 			goto out_free;
 		}

 		priv->is_master = 1;
 		/* take another reference for the copy in the local file priv */
 		priv->master = drm_master_get(priv->minor->master);

 		priv->authenticated = 1;

 		mutex_unlock(&dev->struct_mutex);
 		if (dev->driver->master_create) {
 			ret = dev->driver->master_create(dev, priv->master);
 			if (ret) {
 				mutex_lock(&dev->struct_mutex);
 				/* drop both references if this fails */
 				drm_master_put(&priv->minor->master);
 				drm_master_put(&priv->master);
 				mutex_unlock(&dev->struct_mutex);
 				goto out_free;
 			}
 		}
 		mutex_lock(&dev->struct_mutex);
 		if (dev->driver->master_set) {
 			ret = dev->driver->master_set(dev, priv, true);
 			if (ret) {
 				/* drop both references if this fails */
 				drm_master_put(&priv->minor->master);
 				drm_master_put(&priv->master);
 				mutex_unlock(&dev->struct_mutex);
 				goto out_free;
 			}
 		}
 		mutex_unlock(&dev->struct_mutex);
 	} else {
 		/* get a reference to the master */
 		priv->master = drm_master_get(priv->minor->master);
 		mutex_unlock(&dev->struct_mutex);
 	}

 	mutex_lock(&dev->struct_mutex);
 	list_add(&priv->lhead, &dev->filelist);
 	mutex_unlock(&dev->struct_mutex);

 #ifdef __alpha__
 	/*
 	 * Default the hose
 	 */
 	if (!dev->hose) {
 		struct pci_dev *pci_dev;
 		pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
 		if (pci_dev) {
 			dev->hose = pci_dev->sysdata;
 			pci_dev_put(pci_dev);
 		}
 		if (!dev->hose) {
 			struct pci_bus *b = pci_bus_b(pci_root_buses.next);
 			if (b)
 				dev->hose = b->sysdata;
 		}
 	}
 #endif

 	return 0;
       out_free:
 	kfree(priv);
 	filp->private_data = NULL;
 	return ret;
 }

 /** No-op. */
 int drm_fasync(int fd, struct file *filp, int on)
 {
 	struct drm_file *priv = filp->private_data;
 	struct drm_device *dev = priv->minor->dev;

 	DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
 		  (long)old_encode_dev(priv->minor->device));
 	return fasync_helper(fd, filp, on, &dev->buf_async);
 }
 EXPORT_SYMBOL(drm_fasync);

 static void drm_master_release(struct drm_device *dev, struct file *filp)
 {
 	struct drm_file *file_priv = filp->private_data;

 	if (drm_i_have_hw_lock(dev, file_priv)) {
 		DRM_DEBUG("File %p released, freeing lock for context %d\n",
 			  filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
 		drm_lock_free(&file_priv->master->lock,
 			      _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
 	}
 }

 static void drm_events_release(struct drm_file *file_priv)
 {
 	struct drm_device *dev = file_priv->minor->dev;
 	struct drm_pending_event *e, *et;
 	struct drm_pending_vblank_event *v, *vt;
 	unsigned long flags;

 	spin_lock_irqsave(&dev->event_lock, flags);

 	/* Remove pending flips */
 	list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link)
 		if (v->base.file_priv == file_priv) {
 			list_del(&v->base.link);
 			drm_vblank_put(dev, v->pipe);
 			v->base.destroy(&v->base);
 		}

 	/* Remove unconsumed events */
 	list_for_each_entry_safe(e, et, &file_priv->event_list, link)
 		e->destroy(e);

 	spin_unlock_irqrestore(&dev->event_lock, flags);
 }

 /**
  * Release file.
  *
  * \param inode device inode
  * \param file_priv DRM file private.
  * \return zero on success or a negative number on failure.
  *
  * If the hardware lock is held then free it, and take it again for the kernel
  * context since it's necessary to reclaim buffers. Unlink the file private
  * data from its list and free it. Decreases the open count and if it reaches
  * zero calls drm_lastclose().
  */
 int drm_release(struct inode *inode, struct file *filp)
 {
 	struct drm_file *file_priv = filp->private_data;
 	struct drm_device *dev = file_priv->minor->dev;
 	int retcode = 0;

 	mutex_lock(&drm_global_mutex);

 	DRM_DEBUG("open_count = %d\n", dev->open_count);

 	if (dev->driver->preclose)
 		dev->driver->preclose(dev, file_priv);

 	/* ========================================================
 	 * Begin inline drm_release
 	 */

 	DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
 		  task_pid_nr(current),
 		  (long)old_encode_dev(file_priv->minor->device),
 		  dev->open_count);

 	/* Release any auth tokens that might point to this file_priv,
 	   (do that under the drm_global_mutex) */
 	if (file_priv->magic)
 		(void) drm_remove_magic(file_priv->master, file_priv->magic);

 	/* if the master has gone away we can't do anything with the lock */
 	if (file_priv->minor->master)
 		drm_master_release(dev, filp);

 	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA))
 		drm_core_reclaim_buffers(dev, file_priv);

 	drm_events_release(file_priv);

 	if (dev->driver->driver_features & DRIVER_MODESET)
 		drm_fb_release(file_priv);

 	if (dev->driver->driver_features & DRIVER_GEM)
 		drm_gem_release(dev, file_priv);

 	mutex_lock(&dev->ctxlist_mutex);
 	if (!list_empty(&dev->ctxlist)) {
 		struct drm_ctx_list *pos, *n;

 		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 			if (pos->tag == file_priv &&
 			    pos->handle != DRM_KERNEL_CONTEXT) {
 				if (dev->driver->context_dtor)
 					dev->driver->context_dtor(dev,
 								  pos->handle);

 				drm_ctxbitmap_free(dev, pos->handle);

 				list_del(&pos->head);
 				kfree(pos);
 				--dev->ctx_count;
 			}
 		}
 	}
 	mutex_unlock(&dev->ctxlist_mutex);

 	mutex_lock(&dev->struct_mutex);

 	if (file_priv->is_master) {
 		struct drm_master *master = file_priv->master;
 		struct drm_file *temp;
 		list_for_each_entry(temp, &dev->filelist, lhead) {
 			if ((temp->master == file_priv->master) &&
 			    (temp != file_priv))
 				temp->authenticated = 0;
 		}

 		/**
 		 * Since the master is disappearing, so is the
 		 * possibility to lock.
 		 */

 		if (master->lock.hw_lock) {
 			if (dev->sigdata.lock == master->lock.hw_lock)
 				dev->sigdata.lock = NULL;
 			master->lock.hw_lock = NULL;
 			master->lock.file_priv = NULL;
 			wake_up_interruptible_all(&master->lock.lock_queue);
 		}

 		if (file_priv->minor->master == file_priv->master) {
 			/* drop the reference held my the minor */
 			if (dev->driver->master_drop)
 				dev->driver->master_drop(dev, file_priv, true);
 			drm_master_put(&file_priv->minor->master);
 		}
 	}

 	BUG_ON(dev->dev_mapping == NULL);
 	iput(container_of(dev->dev_mapping, struct inode, i_data));

 	/* drop the reference held my the file priv */
 	drm_master_put(&file_priv->master);
 	file_priv->is_master = 0;
 	list_del(&file_priv->lhead);
 	mutex_unlock(&dev->struct_mutex);

 	if (dev->driver->postclose)
 		dev->driver->postclose(dev, file_priv);

 	if (drm_core_check_feature(dev, DRIVER_PRIME))
 		drm_prime_destroy_file_private(&file_priv->prime);

 	put_pid(file_priv->pid);
 	kfree(file_priv);

 	/* ========================================================
 	 * End inline drm_release
 	 */

 	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
 	if (!--dev->open_count) {
 		if (atomic_read(&dev->ioctl_count)) {
 			DRM_ERROR("Device busy: %d\n",
 				  atomic_read(&dev->ioctl_count));
 			retcode = -EBUSY;
 		} else
 			retcode = drm_lastclose(dev);
 		if (drm_device_is_unplugged(dev))
 			drm_put_dev(dev);
 	}
 	mutex_unlock(&drm_global_mutex);

 	return retcode;
 }
 EXPORT_SYMBOL(drm_release);

 static bool
 drm_dequeue_event(struct drm_file *file_priv,
 		  size_t total, size_t max, struct drm_pending_event **out)
 {
 	struct drm_device *dev = file_priv->minor->dev;
 	struct drm_pending_event *e;
 	unsigned long flags;
 	bool ret = false;

 	spin_lock_irqsave(&dev->event_lock, flags);

 	*out = NULL;
 	if (list_empty(&file_priv->event_list))
 		goto out;
 	e = list_first_entry(&file_priv->event_list,
 			     struct drm_pending_event, link);
 	if (e->event->length + total > max)
 		goto out;

 	file_priv->event_space += e->event->length;
 	list_del(&e->link);
 	*out = e;
 	ret = true;

 out:
 	spin_unlock_irqrestore(&dev->event_lock, flags);
 	return ret;
 }

 ssize_t drm_read(struct file *filp, char __user *buffer,
 		 size_t count, loff_t *offset)
 {
 	struct drm_file *file_priv = filp->private_data;
 	struct drm_pending_event *e;
 	size_t total;
 	ssize_t ret;

 	ret = wait_event_interruptible(file_priv->event_wait,
 				       !list_empty(&file_priv->event_list));
 	if (ret < 0)
 		return ret;

 	total = 0;
 	while (drm_dequeue_event(file_priv, total, count, &e)) {
 		if (copy_to_user(buffer + total,
 				 e->event, e->event->length)) {
 			total = -EFAULT;
 			break;
 		}

 		total += e->event->length;
 		e->destroy(e);
 	}

 	return total;
 }
 EXPORT_SYMBOL(drm_read);

 unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
 {
 	struct drm_file *file_priv = filp->private_data;
 	unsigned int mask = 0;

 	poll_wait(filp, &file_priv->event_wait, wait);

 	if (!list_empty(&file_priv->event_list))
 		mask |= POLLIN | POLLRDNORM;

 	return mask;
 }
 EXPORT_SYMBOL(drm_poll);
	/**
	* \file drm_fops.c
	* File operations for DRM
	*
	* \author Rickard E. (Rik) Faith <faith@valinux.com>
	* \author Daryll Strauss <daryll@valinux.com>
	* \author Gareth Hughes <gareth@valinux.com>
	*/

	/*
	* Created: Mon Jan 4 08:58:31 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 <drm/drmP.h>
	#include <linux/poll.h>
	#include <linux/slab.h>
	#include <linux/module.h>

	/* from BKL pushdown: note that nothing else serializes idr_find() */
	DEFINE_MUTEX(drm_global_mutex);
	EXPORT_SYMBOL(drm_global_mutex);

	static int drm_open_helper(struct inode inode, struct file filp,
	struct drm_device * dev);

	static int drm_setup(struct drm_device * dev)
	{
	int i;
	int ret;

	if (dev->driver->firstopen) {
	ret = dev->driver->firstopen(dev);
	if (ret != 0)
	return ret;
	}

	atomic_set(&dev->ioctl_count, 0);
	atomic_set(&dev->vma_count, 0);

	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
	!drm_core_check_feature(dev, DRIVER_MODESET)) {
	dev->buf_use = 0;
	atomic_set(&dev->buf_alloc, 0);

	i = drm_dma_setup(dev);
	if (i < 0)
	return i;
	}

	for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
	atomic_set(&dev->counts[i], 0);

	dev->sigdata.lock = NULL;

	dev->context_flag = 0;
	dev->interrupt_flag = 0;
	dev->dma_flag = 0;
	dev->last_context = 0;
	dev->last_switch = 0;
	dev->last_checked = 0;
	init_waitqueue_head(&dev->context_wait);
	dev->if_version = 0;

	dev->ctx_start = 0;
	dev->lck_start = 0;

	dev->buf_async = NULL;
	init_waitqueue_head(&dev->buf_readers);
	init_waitqueue_head(&dev->buf_writers);

	DRM_DEBUG("\n");

	/*
	* The kernel's context could be created here, but is now created
	* in drm_dma_enqueue. This is more resource-efficient for
	* hardware that does not do DMA, but may mean that
	* drm_select_queue fails between the time the interrupt is
	* initialized and the time the queues are initialized.
	*/

	return 0;
	}

	/**
	* Open file.
	*
	* \param inode device inode
	* \param filp file pointer.
	* \return zero on success or a negative number on failure.
	*
	* Searches the DRM device with the same minor number, calls open_helper(), and
	* increments the device open count. If the open count was previous at zero,
	* i.e., it's the first that the device is open, then calls setup().
	*/
	int drm_open(struct inode inode, struct file filp)
	{
	struct drm_device *dev = NULL;
	int minor_id = iminor(inode);
	struct drm_minor *minor;
	int retcode = 0;
	int need_setup = 0;
	struct address_space *old_mapping;

	minor = idr_find(&drm_minors_idr, minor_id);
	if (!minor)
	return -ENODEV;

	if (!(dev = minor->dev))
	return -ENODEV;

	if (drm_device_is_unplugged(dev))
	return -ENODEV;

	if (!dev->open_count++)
	need_setup = 1;
	mutex_lock(&dev->struct_mutex);
	old_mapping = dev->dev_mapping;
	if (old_mapping == NULL)
	dev->dev_mapping = &inode->i_data;
	/* ihold ensures nobody can remove inode with our i_data */
	ihold(container_of(dev->dev_mapping, struct inode, i_data));
	inode->i_mapping = dev->dev_mapping;
	filp->f_mapping = dev->dev_mapping;
	mutex_unlock(&dev->struct_mutex);

	retcode = drm_open_helper(inode, filp, dev);
	if (retcode)
	goto err_undo;
	atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
	if (need_setup) {
	retcode = drm_setup(dev);
	if (retcode)
	goto err_undo;
	}
	return 0;

	err_undo:
	mutex_lock(&dev->struct_mutex);
	filp->f_mapping = old_mapping;
	inode->i_mapping = old_mapping;
	iput(container_of(dev->dev_mapping, struct inode, i_data));
	dev->dev_mapping = old_mapping;
	mutex_unlock(&dev->struct_mutex);
	dev->open_count--;
	return retcode;
	}
	EXPORT_SYMBOL(drm_open);

	/**
	* File \c open operation.
	*
	* \param inode device inode.
	* \param filp file pointer.
	*
	* Puts the dev->fops corresponding to the device minor number into
	* \p filp, call the \c open method, and restore the file operations.
	*/
	int drm_stub_open(struct inode inode, struct file filp)
	{
	struct drm_device *dev = NULL;
	struct drm_minor *minor;
	int minor_id = iminor(inode);
	int err = -ENODEV;
	const struct file_operations *old_fops;

	DRM_DEBUG("\n");

	mutex_lock(&drm_global_mutex);
	minor = idr_find(&drm_minors_idr, minor_id);
	if (!minor)
	goto out;

	if (!(dev = minor->dev))
	goto out;

	if (drm_device_is_unplugged(dev))
	goto out;

	old_fops = filp->f_op;
	filp->f_op = fops_get(dev->driver->fops);
	if (filp->f_op == NULL) {
	filp->f_op = old_fops;
	goto out;
	}
	if (filp->f_op->open && (err = filp->f_op->open(inode, filp))) {
	fops_put(filp->f_op);
	filp->f_op = fops_get(old_fops);
	}
	fops_put(old_fops);

	out:
	mutex_unlock(&drm_global_mutex);
	return err;
	}

	/**
	* Check whether DRI will run on this CPU.
	*
	* \return non-zero if the DRI will run on this CPU, or zero otherwise.
	*/
	static int drm_cpu_valid(void)
	{
	#if defined(__i386__)
	if (boot_cpu_data.x86 == 3)
	return 0; /* No cmpxchg on a 386 */
	#endif
	#if defined(__sparc__) && !defined(__sparc_v9__)
	return 0; /* No cmpxchg before v9 sparc. */
	#endif
	return 1;
	}

	/**
	* Called whenever a process opens /dev/drm.
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param dev device.
	* \return zero on success or a negative number on failure.
	*
	* Creates and initializes a drm_file structure for the file private data in \p
	* filp and add it into the double linked list in \p dev.
	*/
	static int drm_open_helper(struct inode inode, struct file filp,
	struct drm_device * dev)
	{
	int minor_id = iminor(inode);
	struct drm_file *priv;
	int ret;

	if (filp->f_flags & O_EXCL)
	return -EBUSY; /* No exclusive opens */
	if (!drm_cpu_valid())
	return -EINVAL;
	if (dev->switch_power_state != DRM_SWITCH_POWER_ON)
	return -EINVAL;

	DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor_id);

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	filp->private_data = priv;
	priv->filp = filp;
	priv->uid = current_euid();
	priv->pid = get_pid(task_pid(current));
	priv->minor = idr_find(&drm_minors_idr, minor_id);
	priv->ioctl_count = 0;
	/* for compatibility root is always authenticated */
	priv->authenticated = capable(CAP_SYS_ADMIN);
	priv->lock_count = 0;

	INIT_LIST_HEAD(&priv->lhead);
	INIT_LIST_HEAD(&priv->fbs);
	INIT_LIST_HEAD(&priv->event_list);
	init_waitqueue_head(&priv->event_wait);
	priv->event_space = 4096; /* set aside 4k for event buffer */

	if (dev->driver->driver_features & DRIVER_GEM)
	drm_gem_open(dev, priv);

	if (drm_core_check_feature(dev, DRIVER_PRIME))
	drm_prime_init_file_private(&priv->prime);

	if (dev->driver->open) {
	ret = dev->driver->open(dev, priv);
	if (ret < 0)
	goto out_free;
	}


	/* if there is no current master make this fd it */
	mutex_lock(&dev->struct_mutex);
	if (!priv->minor->master) {
	/* create a new master */
	priv->minor->master = drm_master_create(priv->minor);
	if (!priv->minor->master) {
	mutex_unlock(&dev->struct_mutex);
	ret = -ENOMEM;
	goto out_free;
	}

	priv->is_master = 1;
	/* take another reference for the copy in the local file priv */
	priv->master = drm_master_get(priv->minor->master);

	priv->authenticated = 1;

	mutex_unlock(&dev->struct_mutex);
	if (dev->driver->master_create) {
	ret = dev->driver->master_create(dev, priv->master);
	if (ret) {
	mutex_lock(&dev->struct_mutex);
	/* drop both references if this fails */
	drm_master_put(&priv->minor->master);
	drm_master_put(&priv->master);
	mutex_unlock(&dev->struct_mutex);
	goto out_free;
	}
	}
	mutex_lock(&dev->struct_mutex);
	if (dev->driver->master_set) {
	ret = dev->driver->master_set(dev, priv, true);
	if (ret) {
	/* drop both references if this fails */
	drm_master_put(&priv->minor->master);
	drm_master_put(&priv->master);
	mutex_unlock(&dev->struct_mutex);
	goto out_free;
	}
	}
	mutex_unlock(&dev->struct_mutex);
	} else {
	/* get a reference to the master */
	priv->master = drm_master_get(priv->minor->master);
	mutex_unlock(&dev->struct_mutex);
	}

	mutex_lock(&dev->struct_mutex);
	list_add(&priv->lhead, &dev->filelist);
	mutex_unlock(&dev->struct_mutex);

	#ifdef __alpha__
	/*
	* Default the hose
	*/
	if (!dev->hose) {
	struct pci_dev *pci_dev;
	pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
	if (pci_dev) {
	dev->hose = pci_dev->sysdata;
	pci_dev_put(pci_dev);
	}
	if (!dev->hose) {
	struct pci_bus *b = pci_bus_b(pci_root_buses.next);
	if (b)
	dev->hose = b->sysdata;
	}
	}
	#endif

	return 0;
	out_free:
	kfree(priv);
	filp->private_data = NULL;
	return ret;
	}

	/** No-op. */
	int drm_fasync(int fd, struct file *filp, int on)
	{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->minor->dev;

	DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
	(long)old_encode_dev(priv->minor->device));
	return fasync_helper(fd, filp, on, &dev->buf_async);
	}
	EXPORT_SYMBOL(drm_fasync);

	static void drm_master_release(struct drm_device dev, struct file filp)
	{
	struct drm_file *file_priv = filp->private_data;

	if (drm_i_have_hw_lock(dev, file_priv)) {
	DRM_DEBUG("File %p released, freeing lock for context %d\n",
	filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
	drm_lock_free(&file_priv->master->lock,
	_DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
	}
	}

	static void drm_events_release(struct drm_file *file_priv)
	{
	struct drm_device *dev = file_priv->minor->dev;
	struct drm_pending_event e, et;
	struct drm_pending_vblank_event v, vt;
	unsigned long flags;

	spin_lock_irqsave(&dev->event_lock, flags);

	/* Remove pending flips */
	list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link)
	if (v->base.file_priv == file_priv) {
	list_del(&v->base.link);
	drm_vblank_put(dev, v->pipe);
	v->base.destroy(&v->base);
	}

	/* Remove unconsumed events */
	list_for_each_entry_safe(e, et, &file_priv->event_list, link)
	e->destroy(e);

	spin_unlock_irqrestore(&dev->event_lock, flags);
	}

	/**
	* Release file.
	*
	* \param inode device inode
	* \param file_priv DRM file private.
	* \return zero on success or a negative number on failure.
	*
	* If the hardware lock is held then free it, and take it again for the kernel
	* context since it's necessary to reclaim buffers. Unlink the file private
	* data from its list and free it. Decreases the open count and if it reaches
	* zero calls drm_lastclose().
	*/
	int drm_release(struct inode inode, struct file filp)
	{
	struct drm_file *file_priv = filp->private_data;
	struct drm_device *dev = file_priv->minor->dev;
	int retcode = 0;

	mutex_lock(&drm_global_mutex);

	DRM_DEBUG("open_count = %d\n", dev->open_count);

	if (dev->driver->preclose)
	dev->driver->preclose(dev, file_priv);

	/* ========================================================
	* Begin inline drm_release
	*/

	DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
	task_pid_nr(current),
	(long)old_encode_dev(file_priv->minor->device),
	dev->open_count);

	/* Release any auth tokens that might point to this file_priv,
	(do that under the drm_global_mutex) */
	if (file_priv->magic)
	(void) drm_remove_magic(file_priv->master, file_priv->magic);

	/* if the master has gone away we can't do anything with the lock */
	if (file_priv->minor->master)
	drm_master_release(dev, filp);

	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA))
	drm_core_reclaim_buffers(dev, file_priv);

	drm_events_release(file_priv);

	if (dev->driver->driver_features & DRIVER_MODESET)
	drm_fb_release(file_priv);

	if (dev->driver->driver_features & DRIVER_GEM)
	drm_gem_release(dev, file_priv);

	mutex_lock(&dev->ctxlist_mutex);
	if (!list_empty(&dev->ctxlist)) {
	struct drm_ctx_list pos, n;

	list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
	if (pos->tag == file_priv &&
	pos->handle != DRM_KERNEL_CONTEXT) {
	if (dev->driver->context_dtor)
	dev->driver->context_dtor(dev,
	pos->handle);

	drm_ctxbitmap_free(dev, pos->handle);

	list_del(&pos->head);
	kfree(pos);
	--dev->ctx_count;
	}
	}
	}
	mutex_unlock(&dev->ctxlist_mutex);

	mutex_lock(&dev->struct_mutex);

	if (file_priv->is_master) {
	struct drm_master *master = file_priv->master;
	struct drm_file *temp;
	list_for_each_entry(temp, &dev->filelist, lhead) {
	if ((temp->master == file_priv->master) &&
	(temp != file_priv))
	temp->authenticated = 0;
	}

	/**
	* Since the master is disappearing, so is the
	* possibility to lock.
	*/

	if (master->lock.hw_lock) {
	if (dev->sigdata.lock == master->lock.hw_lock)
	dev->sigdata.lock = NULL;
	master->lock.hw_lock = NULL;
	master->lock.file_priv = NULL;
	wake_up_interruptible_all(&master->lock.lock_queue);
	}

	if (file_priv->minor->master == file_priv->master) {
	/* drop the reference held my the minor */
	if (dev->driver->master_drop)
	dev->driver->master_drop(dev, file_priv, true);
	drm_master_put(&file_priv->minor->master);
	}
	}

	BUG_ON(dev->dev_mapping == NULL);
	iput(container_of(dev->dev_mapping, struct inode, i_data));

	/* drop the reference held my the file priv */
	drm_master_put(&file_priv->master);
	file_priv->is_master = 0;
	list_del(&file_priv->lhead);
	mutex_unlock(&dev->struct_mutex);

	if (dev->driver->postclose)
	dev->driver->postclose(dev, file_priv);

	if (drm_core_check_feature(dev, DRIVER_PRIME))
	drm_prime_destroy_file_private(&file_priv->prime);

	put_pid(file_priv->pid);
	kfree(file_priv);

	/* ========================================================
	* End inline drm_release
	*/

	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
	if (!--dev->open_count) {
	if (atomic_read(&dev->ioctl_count)) {
	DRM_ERROR("Device busy: %d\n",
	atomic_read(&dev->ioctl_count));
	retcode = -EBUSY;
	} else
	retcode = drm_lastclose(dev);
	if (drm_device_is_unplugged(dev))
	drm_put_dev(dev);
	}
	mutex_unlock(&drm_global_mutex);

	return retcode;
	}
	EXPORT_SYMBOL(drm_release);

	static bool
	drm_dequeue_event(struct drm_file *file_priv,
	size_t total, size_t max, struct drm_pending_event **out)
	{
	struct drm_device *dev = file_priv->minor->dev;
	struct drm_pending_event *e;
	unsigned long flags;
	bool ret = false;

	spin_lock_irqsave(&dev->event_lock, flags);

	*out = NULL;
	if (list_empty(&file_priv->event_list))
	goto out;
	e = list_first_entry(&file_priv->event_list,
	struct drm_pending_event, link);
	if (e->event->length + total > max)
	goto out;

	file_priv->event_space += e->event->length;
	list_del(&e->link);
	*out = e;
	ret = true;

	out:
	spin_unlock_irqrestore(&dev->event_lock, flags);
	return ret;
	}

	ssize_t drm_read(struct file filp, char __user buffer,
	size_t count, loff_t *offset)
	{
	struct drm_file *file_priv = filp->private_data;
	struct drm_pending_event *e;
	size_t total;
	ssize_t ret;

	ret = wait_event_interruptible(file_priv->event_wait,
	!list_empty(&file_priv->event_list));
	if (ret < 0)
	return ret;

	total = 0;
	while (drm_dequeue_event(file_priv, total, count, &e)) {
	if (copy_to_user(buffer + total,
	e->event, e->event->length)) {
	total = -EFAULT;
	break;
	}

	total += e->event->length;
	e->destroy(e);
	}

	return total;
	}
	EXPORT_SYMBOL(drm_read);

	unsigned int drm_poll(struct file filp, struct poll_table_struct wait)
	{
	struct drm_file *file_priv = filp->private_data;
	unsigned int mask = 0;

	poll_wait(filp, &file_priv->event_wait, wait);

	if (!list_empty(&file_priv->event_list))
	mask \|= POLLIN \| POLLRDNORM;

	return mask;
	}
	EXPORT_SYMBOL(drm_poll);