drivers/gpu/drm/drm_fops.c - kernel/msm - Gitiles

 /**
  * \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 "drmP.h"
 #include <linux/poll.h>
 #include <linux/smp_lock.h>

 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->queue_count = 0;
 	dev->queue_reserved = 0;
 	dev->queue_slots = 0;
 	dev->queuelist = 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;

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

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

 	retcode = drm_open_helper(inode, filp, dev);
 	if (!retcode) {
 		atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
 		spin_lock(&dev->count_lock);
 		if (!dev->open_count++) {
 			spin_unlock(&dev->count_lock);
 			retcode = drm_setup(dev);
 			goto out;
 		}
 		spin_unlock(&dev->count_lock);
 	}
 out:
 	mutex_lock(&dev->struct_mutex);
 	if (minor->type == DRM_MINOR_LEGACY) {
 		BUG_ON((dev->dev_mapping != NULL) &&
 			(dev->dev_mapping != inode->i_mapping));
 		if (dev->dev_mapping == NULL)
 			dev->dev_mapping = inode->i_mapping;
 	}
 	mutex_unlock(&dev->struct_mutex);

 	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");

 	/* BKL pushdown: note that nothing else serializes idr_find() */
 	lock_kernel();
 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (!minor)
 		goto out;

 	if (!(dev = minor->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:
 	unlock_kernel();
 	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;

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

 	priv = drm_alloc(sizeof(*priv), DRM_MEM_FILES);
 	if (!priv)
 		return -ENOMEM;

 	memset(priv, 0, sizeof(*priv));
 	filp->private_data = priv;
 	priv->filp = filp;
 	priv->uid = current_euid();
 	priv->pid = task_pid_nr(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);

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

 	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) {
 			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;
 			}
 		}
 	} 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:
 	drm_free(priv, sizeof(*priv), DRM_MEM_FILES);
 	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;
 	int retcode;

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

 /*
  * Reclaim locked buffers; note that this may be a bad idea if the current
  * context doesn't have the hw lock...
  */
 static void drm_reclaim_locked_buffers(struct drm_device *dev, struct file *f)
 {
 	struct drm_file *file_priv = f->private_data;

 	if (drm_i_have_hw_lock(dev, file_priv)) {
 		dev->driver->reclaim_buffers_locked(dev, file_priv);
 	} else {
 		unsigned long _end = jiffies + 3 * DRM_HZ;
 		int locked = 0;

 		drm_idlelock_take(&file_priv->master->lock);

 		/*
 		 * Wait for a while.
 		 */
 		do {
 			spin_lock_bh(&file_priv->master->lock.spinlock);
 			locked = file_priv->master->lock.idle_has_lock;
 			spin_unlock_bh(&file_priv->master->lock.spinlock);
 			if (locked)
 				break;
 			schedule();
 		} while (!time_after_eq(jiffies, _end));

 		if (!locked) {
 			DRM_ERROR("reclaim_buffers_locked() deadlock. Please rework this\n"
 				  "\tdriver to use reclaim_buffers_idlelocked() instead.\n"
 				  "\tI will go on reclaiming the buffers anyway.\n");
 		}

 		dev->driver->reclaim_buffers_locked(dev, file_priv);
 		drm_idlelock_release(&file_priv->master->lock);
 	}
 }

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

 	if (dev->driver->reclaim_buffers_locked &&
 	    file_priv->master->lock.hw_lock)
 		drm_reclaim_locked_buffers(dev, filp);

 	if (dev->driver->reclaim_buffers_idlelocked &&
 	    file_priv->master->lock.hw_lock) {
 		drm_idlelock_take(&file_priv->master->lock);
 		dev->driver->reclaim_buffers_idlelocked(dev, file_priv);
 		drm_idlelock_release(&file_priv->master->lock);
 	}


 	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));
 	}

 	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
 	    !dev->driver->reclaim_buffers_locked) {
 		dev->driver->reclaim_buffers(dev, file_priv);
 	}
 }

 /**
  * 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;

 	lock_kernel();

 	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);

 	/* 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 (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);
 				drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
 				--dev->ctx_count;
 			}
 		}
 	}
 	mutex_unlock(&dev->ctxlist_mutex);

 	mutex_lock(&dev->struct_mutex);

 	if (file_priv->is_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;
 		}

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

 	/* 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);
 	drm_free(file_priv, sizeof(*file_priv), DRM_MEM_FILES);

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

 	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
 	spin_lock(&dev->count_lock);
 	if (!--dev->open_count) {
 		if (atomic_read(&dev->ioctl_count)) {
 			DRM_ERROR("Device busy: %d\n",
 				  atomic_read(&dev->ioctl_count));
 			spin_unlock(&dev->count_lock);
 			unlock_kernel();
 			return -EBUSY;
 		}
 		spin_unlock(&dev->count_lock);
 		unlock_kernel();
 		return drm_lastclose(dev);
 	}
 	spin_unlock(&dev->count_lock);

 	unlock_kernel();

 	return retcode;
 }
 EXPORT_SYMBOL(drm_release);

 /** No-op. */
 unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
 {
 	return 0;
 }
 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 "drmP.h"
	#include <linux/poll.h>
	#include <linux/smp_lock.h>

	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->queue_count = 0;
	dev->queue_reserved = 0;
	dev->queue_slots = 0;
	dev->queuelist = 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;

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

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

	retcode = drm_open_helper(inode, filp, dev);
	if (!retcode) {
	atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
	spin_lock(&dev->count_lock);
	if (!dev->open_count++) {
	spin_unlock(&dev->count_lock);
	retcode = drm_setup(dev);
	goto out;
	}
	spin_unlock(&dev->count_lock);
	}
	out:
	mutex_lock(&dev->struct_mutex);
	if (minor->type == DRM_MINOR_LEGACY) {
	BUG_ON((dev->dev_mapping != NULL) &&
	(dev->dev_mapping != inode->i_mapping));
	if (dev->dev_mapping == NULL)
	dev->dev_mapping = inode->i_mapping;
	}
	mutex_unlock(&dev->struct_mutex);

	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");

	/* BKL pushdown: note that nothing else serializes idr_find() */
	lock_kernel();
	minor = idr_find(&drm_minors_idr, minor_id);
	if (!minor)
	goto out;

	if (!(dev = minor->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:
	unlock_kernel();
	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;

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

	priv = drm_alloc(sizeof(*priv), DRM_MEM_FILES);
	if (!priv)
	return -ENOMEM;

	memset(priv, 0, sizeof(*priv));
	filp->private_data = priv;
	priv->filp = filp;
	priv->uid = current_euid();
	priv->pid = task_pid_nr(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);

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

	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) {
	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;
	}
	}
	} 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:
	drm_free(priv, sizeof(*priv), DRM_MEM_FILES);
	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;
	int retcode;

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

	/*
	* Reclaim locked buffers; note that this may be a bad idea if the current
	* context doesn't have the hw lock...
	*/
	static void drm_reclaim_locked_buffers(struct drm_device dev, struct file f)
	{
	struct drm_file *file_priv = f->private_data;

	if (drm_i_have_hw_lock(dev, file_priv)) {
	dev->driver->reclaim_buffers_locked(dev, file_priv);
	} else {
	unsigned long _end = jiffies + 3 * DRM_HZ;
	int locked = 0;

	drm_idlelock_take(&file_priv->master->lock);

	/*
	* Wait for a while.
	*/
	do {
	spin_lock_bh(&file_priv->master->lock.spinlock);
	locked = file_priv->master->lock.idle_has_lock;
	spin_unlock_bh(&file_priv->master->lock.spinlock);
	if (locked)
	break;
	schedule();
	} while (!time_after_eq(jiffies, _end));

	if (!locked) {
	DRM_ERROR("reclaim_buffers_locked() deadlock. Please rework this\n"
	"\tdriver to use reclaim_buffers_idlelocked() instead.\n"
	"\tI will go on reclaiming the buffers anyway.\n");
	}

	dev->driver->reclaim_buffers_locked(dev, file_priv);
	drm_idlelock_release(&file_priv->master->lock);
	}
	}

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

	if (dev->driver->reclaim_buffers_locked &&
	file_priv->master->lock.hw_lock)
	drm_reclaim_locked_buffers(dev, filp);

	if (dev->driver->reclaim_buffers_idlelocked &&
	file_priv->master->lock.hw_lock) {
	drm_idlelock_take(&file_priv->master->lock);
	dev->driver->reclaim_buffers_idlelocked(dev, file_priv);
	drm_idlelock_release(&file_priv->master->lock);
	}


	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));
	}

	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
	!dev->driver->reclaim_buffers_locked) {
	dev->driver->reclaim_buffers(dev, file_priv);
	}
	}

	/**
	* 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;

	lock_kernel();

	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);

	/* 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 (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);
	drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
	--dev->ctx_count;
	}
	}
	}
	mutex_unlock(&dev->ctxlist_mutex);

	mutex_lock(&dev->struct_mutex);

	if (file_priv->is_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;
	}

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

	/* 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);
	drm_free(file_priv, sizeof(*file_priv), DRM_MEM_FILES);

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

	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
	spin_lock(&dev->count_lock);
	if (!--dev->open_count) {
	if (atomic_read(&dev->ioctl_count)) {
	DRM_ERROR("Device busy: %d\n",
	atomic_read(&dev->ioctl_count));
	spin_unlock(&dev->count_lock);
	unlock_kernel();
	return -EBUSY;
	}
	spin_unlock(&dev->count_lock);
	unlock_kernel();
	return drm_lastclose(dev);
	}
	spin_unlock(&dev->count_lock);

	unlock_kernel();

	return retcode;
	}
	EXPORT_SYMBOL(drm_release);

	/** No-op. */
	unsigned int drm_poll(struct file filp, struct poll_table_struct wait)
	{
	return 0;
	}
	EXPORT_SYMBOL(drm_poll);