text: /*
   * Legacy: Generic DRM Buffer Management
   *
   * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
   * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
   * All Rights Reserved.
   *
   * Author: Rickard E. (Rik) Faith <faith@valinux.com>
   * Author: Gareth Hughes <gareth@valinux.com>
   *
   * 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 <linux/vmalloc.h>
  #include <linux/slab.h>
  #include <linux/log2.h>
  #include <linux/export.h>
  #include <asm/shmparam.h>
  #include <drm/drmP.h>
  #include "drm_legacy.h"
  
  #include <linux/nospec.h>
  
  static struct drm_map_list *drm_find_matching_map(struct drm_device *dev,
  						  struct drm_local_map *map)
  {
  	struct drm_map_list *entry;
  	list_for_each_entry(entry, &dev->maplist, head) {
  		/*
  		 * Because the kernel-userspace ABI is fixed at a 32-bit offset
  		 * while PCI resources may live above that, we only compare the
  		 * lower 32 bits of the map offset for maps of type
  		 * _DRM_FRAMEBUFFER or _DRM_REGISTERS.
  		 * It is assumed that if a driver have more than one resource
  		 * of each type, the lower 32 bits are different.
  		 */
  		if (!entry->map ||
  		    map->type != entry->map->type ||
  		    entry->master != dev->master)
  			continue;
  		switch (map->type) {
  		case _DRM_SHM:
  			if (map->flags != _DRM_CONTAINS_LOCK)
  				break;
  			return entry;
  		case _DRM_REGISTERS:
  		case _DRM_FRAME_BUFFER:
  			if ((entry->map->offset & 0xffffffff) ==
  			    (map->offset & 0xffffffff))
  				return entry;
  		default: /* Make gcc happy */
  			;
  		}
  		if (entry->map->offset == map->offset)
  			return entry;
  	}
  
  	return NULL;
  }
  
  static int drm_map_handle(struct drm_device *dev, struct drm_hash_item *hash,
  			  unsigned long user_token, int hashed_handle, int shm)
  {
  	int use_hashed_handle, shift;
  	unsigned long add;
  
  #if (BITS_PER_LONG == 64)
  	use_hashed_handle = ((user_token & 0xFFFFFFFF00000000UL) || hashed_handle);
  #elif (BITS_PER_LONG == 32)
  	use_hashed_handle = hashed_handle;
  #else
  #error Unsupported long size. Neither 64 nor 32 bits.
  #endif
  
  	if (!use_hashed_handle) {
  		int ret;
  		hash->key = user_token >> PAGE_SHIFT;
  		ret = drm_ht_insert_item(&dev->map_hash, hash);
  		if (ret != -EINVAL)
  			return ret;
  	}
  
  	shift = 0;
  	add = DRM_MAP_HASH_OFFSET >> PAGE_SHIFT;
  	if (shm && (SHMLBA > PAGE_SIZE)) {
  		int bits = ilog2(SHMLBA >> PAGE_SHIFT) + 1;
  
  		/* For shared memory, we have to preserve the SHMLBA
  		 * bits of the eventual vma->vm_pgoff value during
  		 * mmap().  Otherwise we run into cache aliasing problems
  		 * on some platforms.  On these platforms, the pgoff of
  		 * a mmap() request is used to pick a suitable virtual
  		 * address for the mmap() region such that it will not
  		 * cause cache aliasing problems.
  		 *
  		 * Therefore, make sure the SHMLBA relevant bits of the
  		 * hash value we use are equal to those in the original
  		 * kernel virtual address.
  		 */
  		shift = bits;
  		add |= ((user_token >> PAGE_SHIFT) & ((1UL << bits) - 1UL));
  	}
  
  	return drm_ht_just_insert_please(&dev->map_hash, hash,
  					 user_token, 32 - PAGE_SHIFT - 3,
  					 shift, add);
  }
  
  /**
   * Core function to create a range of memory available for mapping by a
   * non-root process.
   *
   * Adjusts the memory offset to its absolute value according to the mapping
   * type.  Adds the map to the map list drm_device::maplist. Adds MTRR's where
   * applicable and if supported by the kernel.
   */
  static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
  			   unsigned int size, enum drm_map_type type,
  			   enum drm_map_flags flags,
  			   struct drm_map_list ** maplist)
  {
  	struct drm_local_map *map;
  	struct drm_map_list *list;
  	drm_dma_handle_t *dmah;
  	unsigned long user_token;
  	int ret;
  
  	map = kmalloc(sizeof(*map), GFP_KERNEL);
  	if (!map)
  		return -ENOMEM;
  
  	map->offset = offset;
  	map->size = size;
  	map->flags = flags;
  	map->type = type;
  
  	/* Only allow shared memory to be removable since we only keep enough
  	 * book keeping information about shared memory to allow for removal
  	 * when processes fork.
  	 */
  	if ((map->flags & _DRM_REMOVABLE) && map->type != _DRM_SHM) {
  		kfree(map);
  		return -EINVAL;
  	}
  	DRM_DEBUG("offset = 0x%08llx, size = 0x%08lx, type = %d\n",
  		  (unsigned long long)map->offset, map->size, map->type);
  
  	/* page-align _DRM_SHM maps. They are allocated here so there is no security
  	 * hole created by that and it works around various broken drivers that use
  	 * a non-aligned quantity to map the SAREA. --BenH
  	 */
  	if (map->type == _DRM_SHM)
  		map->size = PAGE_ALIGN(map->size);
  
  	if ((map->offset & (~(resource_size_t)PAGE_MASK)) || (map->size & (~PAGE_MASK))) {
  		kfree(map);
  		return -EINVAL;
  	}
  	map->mtrr = -1;
  	map->handle = NULL;
  
  	switch (map->type) {
  	case _DRM_REGISTERS:
  	case _DRM_FRAME_BUFFER:
  #if !defined(__sparc__) && !defined(__alpha__) && !defined(__ia64__) && !defined(__powerpc64__) && !defined(__x86_64__) && !defined(__arm__)
  		if (map->offset + (map->size-1) < map->offset ||
  		    map->offset < virt_to_phys(high_memory)) {
  			kfree(map);
  			return -EINVAL;
  		}
  #endif
  		/* Some drivers preinitialize some maps, without the X Server
  		 * needing to be aware of it.  Therefore, we just return success
  		 * when the server tries to create a duplicate map.
  		 */
  		list = drm_find_matching_map(dev, map);
  		if (list != NULL) {
  			if (list->map->size != map->size) {
  				DRM_DEBUG("Matching maps of type %d with "
  					  "mismatched sizes, (%ld vs %ld)\n",
  					  map->type, map->size,
  					  list->map->size);
  				list->map->size = map->size;
  			}
  
  			kfree(map);
  			*maplist = list;
  			return 0;
  		}
  
  		if (map->type == _DRM_FRAME_BUFFER ||
  		    (map->flags & _DRM_WRITE_COMBINING)) {
  			map->mtrr =
  				arch_phys_wc_add(map->offset, map->size);
  		}
  		if (map->type == _DRM_REGISTERS) {
  			if (map->flags & _DRM_WRITE_COMBINING)
  				map->handle = ioremap_wc(map->offset,
  							 map->size);
  			else
  				map->handle = ioremap(map->offset, map->size);
  			if (!map->handle) {
  				kfree(map);
  				return -ENOMEM;
  			}
  		}
  
  		break;
  	case _DRM_SHM:
  		list = drm_find_matching_map(dev, map);
  		if (list != NULL) {
  			if(list->map->size != map->size) {
  				DRM_DEBUG("Matching maps of type %d with "
  					  "mismatched sizes, (%ld vs %ld)\n",
  					  map->type, map->size, list->map->size);
  				list->map->size = map->size;
  			}
  
  			kfree(map);
  			*maplist = list;
  			return 0;
  		}
  		map->handle = vmalloc_user(map->size);
  		DRM_DEBUG("%lu %d %p\n",
  			  map->size, order_base_2(map->size), map->handle);
  		if (!map->handle) {
  			kfree(map);
  			return -ENOMEM;
  		}
  		map->offset = (unsigned long)map->handle;
  		if (map->flags & _DRM_CONTAINS_LOCK) {
  			/* Prevent a 2nd X Server from creating a 2nd lock */
  			if (dev->master->lock.hw_lock != NULL) {
  				vfree(map->handle);
  				kfree(map);
  				return -EBUSY;
  			}
  			dev->sigdata.lock = dev->master->lock.hw_lock = map->handle;	/* Pointer to lock */
  		}
  		break;
  	case _DRM_AGP: {
  		struct drm_agp_mem *entry;
  		int valid = 0;
  
  		if (!dev->agp) {
  			kfree(map);
  			return -EINVAL;
  		}
  #ifdef __alpha__
  		map->offset += dev->hose->mem_space->start;
  #endif
  		/* In some cases (i810 driver), user space may have already
  		 * added the AGP base itself, because dev->agp->base previously
  		 * only got set during AGP enable.  So, only add the base
  		 * address if the map's offset isn't already within the
  		 * aperture.
  		 */
  		if (map->offset < dev->agp->base ||
  		    map->offset > dev->agp->base +
  		    dev->agp->agp_info.aper_size * 1024 * 1024 - 1) {
  			map->offset += dev->agp->base;
  		}
  		map->mtrr = dev->agp->agp_mtrr;	/* for getmap */
  
  		/* This assumes the DRM is in total control of AGP space.
  		 * It's not always the case as AGP can be in the control
  		 * of user space (i.e. i810 driver). So this loop will get
  		 * skipped and we double check that dev->agp->memory is
  		 * actually set as well as being invalid before EPERM'ing
  		 */
  		list_for_each_entry(entry, &dev->agp->memory, head) {
  			if ((map->offset >= entry->bound) &&
  			    (map->offset + map->size <= entry->bound + entry->pages * PAGE_SIZE)) {
  				valid = 1;
  				break;
  			}
  		}
  		if (!list_empty(&dev->agp->memory) && !valid) {
  			kfree(map);
  			return -EPERM;
  		}
  		DRM_DEBUG("AGP offset = 0x%08llx, size = 0x%08lx\n",
  			  (unsigned long long)map->offset, map->size);
  
  		break;
  	}
  	case _DRM_SCATTER_GATHER:
  		if (!dev->sg) {
  			kfree(map);
  			return -EINVAL;
  		}
  		map->offset += (unsigned long)dev->sg->virtual;
  		break;
  	case _DRM_CONSISTENT:
  		/* dma_addr_t is 64bit on i386 with CONFIG_HIGHMEM64G,
  		 * As we're limiting the address to 2^32-1 (or less),
  		 * casting it down to 32 bits is no problem, but we
  		 * need to point to a 64bit variable first. */
  		dmah = drm_pci_alloc(dev, map->size, map->size);
  		if (!dmah) {
  			kfree(map);
  			return -ENOMEM;
  		}
  		map->handle = dmah->vaddr;
  		map->offset = (unsigned long)dmah->busaddr;
  		kfree(dmah);
  		break;
  	default:
  		kfree(map);
  		return -EINVAL;
  	}
  
  	list = kzalloc(sizeof(*list), GFP_KERNEL);
  	if (!list) {
  		if (map->type == _DRM_REGISTERS)
  			iounmap(map->handle);
  		kfree(map);
  		return -EINVAL;
  	}
  	list->map = map;
  
  	mutex_lock(&dev->struct_mutex);
  	list_add(&list->head, &dev->maplist);
  
  	/* Assign a 32-bit handle */
  	/* We do it here so that dev->struct_mutex protects the increment */
  	user_token = (map->type == _DRM_SHM) ? (unsigned long)map->handle :
  		map->offset;
  	ret = drm_map_handle(dev, &list->hash, user_token, 0,
  			     (map->type == _DRM_SHM));
  	if (ret) {
  		if (map->type == _DRM_REGISTERS)
  			iounmap(map->handle);
  		kfree(map);
  		kfree(list);
  		mutex_unlock(&dev->struct_mutex);
  		return ret;
  	}
  
  	list->user_token = list->hash.key << PAGE_SHIFT;
  	mutex_unlock(&dev->struct_mutex);
  
  	if (!(map->flags & _DRM_DRIVER))
  		list->master = dev->master;
  	*maplist = list;
  	return 0;
  }
  
  int drm_legacy_addmap(struct drm_device * dev, resource_size_t offset,
  		      unsigned int size, enum drm_map_type type,
  		      enum drm_map_flags flags, struct drm_local_map **map_ptr)
  {
  	struct drm_map_list *list;
  	int rc;
  
  	rc = drm_addmap_core(dev, offset, size, type, flags, &list);
  	if (!rc)
  		*map_ptr = list->map;
  	return rc;
  }
  EXPORT_SYMBOL(drm_legacy_addmap);
  
  /**
   * Ioctl to specify a range of memory that is available for mapping by a
   * non-root process.
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg pointer to a drm_map structure.
   * \return zero on success or a negative value on error.
   *
   */
  int drm_legacy_addmap_ioctl(struct drm_device *dev, void *data,
  			    struct drm_file *file_priv)
  {
  	struct drm_map *map = data;
  	struct drm_map_list *maplist;
  	int err;
  
  	if (!(capable(CAP_SYS_ADMIN) || map->type == _DRM_AGP || map->type == _DRM_SHM))
  		return -EPERM;
  
  	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
  	    !drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	err = drm_addmap_core(dev, map->offset, map->size, map->type,
  			      map->flags, &maplist);
  
  	if (err)
  		return err;
  
  	/* avoid a warning on 64-bit, this casting isn't very nice, but the API is set so too late */
  	map->handle = (void *)(unsigned long)maplist->user_token;
  
  	/*
  	 * It appears that there are no users of this value whatsoever --
  	 * drmAddMap just discards it.  Let's not encourage its use.
  	 * (Keeping drm_addmap_core's returned mtrr value would be wrong --
  	 *  it's not a real mtrr index anymore.)
  	 */
  	map->mtrr = -1;
  
  	return 0;
  }
  
  /*
   * Get a mapping information.
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg user argument, pointing to a drm_map structure.
   *
   * \return zero on success or a negative number on failure.
   *
   * Searches for the mapping with the specified offset and copies its information
   * into userspace
   */
  int drm_legacy_getmap_ioctl(struct drm_device *dev, void *data,
  			    struct drm_file *file_priv)
  {
  	struct drm_map *map = data;
  	struct drm_map_list *r_list = NULL;
  	struct list_head *list;
  	int idx;
  	int i;
  
  	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
  	    !drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	idx = map->offset;
  	if (idx < 0)
  		return -EINVAL;
  
  	i = 0;
  	mutex_lock(&dev->struct_mutex);
  	list_for_each(list, &dev->maplist) {
  		if (i == idx) {
  			r_list = list_entry(list, struct drm_map_list, head);
  			break;
  		}
  		i++;
  	}
  	if (!r_list || !r_list->map) {
  		mutex_unlock(&dev->struct_mutex);
  		return -EINVAL;
  	}
  
  	map->offset = r_list->map->offset;
  	map->size = r_list->map->size;
  	map->type = r_list->map->type;
  	map->flags = r_list->map->flags;
  	map->handle = (void *)(unsigned long) r_list->user_token;
  	map->mtrr = arch_phys_wc_index(r_list->map->mtrr);
  
  	mutex_unlock(&dev->struct_mutex);
  
  	return 0;
  }
  
  /**
   * Remove a map private from list and deallocate resources if the mapping
   * isn't in use.
   *
   * Searches the map on drm_device::maplist, removes it from the list, see if
   * its being used, and free any associate resource (such as MTRR's) if it's not
   * being on use.
   *
   * \sa drm_legacy_addmap
   */
  int drm_legacy_rmmap_locked(struct drm_device *dev, struct drm_local_map *map)
  {
  	struct drm_map_list *r_list = NULL, *list_t;
  	drm_dma_handle_t dmah;
  	int found = 0;
  	struct drm_master *master;
  
  	/* Find the list entry for the map and remove it */
  	list_for_each_entry_safe(r_list, list_t, &dev->maplist, head) {
  		if (r_list->map == map) {
  			master = r_list->master;
  			list_del(&r_list->head);
  			drm_ht_remove_key(&dev->map_hash,
  					  r_list->user_token >> PAGE_SHIFT);
  			kfree(r_list);
  			found = 1;
  			break;
  		}
  	}
  
  	if (!found)
  		return -EINVAL;
  
  	switch (map->type) {
  	case _DRM_REGISTERS:
  		iounmap(map->handle);
  		/* FALLTHROUGH */
  	case _DRM_FRAME_BUFFER:
  		arch_phys_wc_del(map->mtrr);
  		break;
  	case _DRM_SHM:
  		vfree(map->handle);
  		if (master) {
  			if (dev->sigdata.lock == master->lock.hw_lock)
  				dev->sigdata.lock = NULL;
  			master->lock.hw_lock = NULL;   /* SHM removed */
  			master->lock.file_priv = NULL;
  			wake_up_interruptible_all(&master->lock.lock_queue);
  		}
  		break;
  	case _DRM_AGP:
  	case _DRM_SCATTER_GATHER:
  		break;
  	case _DRM_CONSISTENT:
  		dmah.vaddr = map->handle;
  		dmah.busaddr = map->offset;
  		dmah.size = map->size;
  		__drm_legacy_pci_free(dev, &dmah);
  		break;
  	}
  	kfree(map);
  
  	return 0;
  }
  EXPORT_SYMBOL(drm_legacy_rmmap_locked);
  
  void drm_legacy_rmmap(struct drm_device *dev, struct drm_local_map *map)
  {
  	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
  	    !drm_core_check_feature(dev, DRIVER_LEGACY))
  		return;
  
  	mutex_lock(&dev->struct_mutex);
  	drm_legacy_rmmap_locked(dev, map);
  	mutex_unlock(&dev->struct_mutex);
  }
  EXPORT_SYMBOL(drm_legacy_rmmap);
  
  void drm_legacy_master_rmmaps(struct drm_device *dev, struct drm_master *master)
  {
  	struct drm_map_list *r_list, *list_temp;
  
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return;
  
  	mutex_lock(&dev->struct_mutex);
  	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head) {
  		if (r_list->master == master) {
  			drm_legacy_rmmap_locked(dev, r_list->map);
  			r_list = NULL;
  		}
  	}
  	mutex_unlock(&dev->struct_mutex);
  }
  
  /* The rmmap ioctl appears to be unnecessary.  All mappings are torn down on
   * the last close of the device, and this is necessary for cleanup when things
   * exit uncleanly.  Therefore, having userland manually remove mappings seems
   * like a pointless exercise since they're going away anyway.
   *
   * One use case might be after addmap is allowed for normal users for SHM and
   * gets used by drivers that the server doesn't need to care about.  This seems
   * unlikely.
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg pointer to a struct drm_map structure.
   * \return zero on success or a negative value on error.
   */
  int drm_legacy_rmmap_ioctl(struct drm_device *dev, void *data,
  			   struct drm_file *file_priv)
  {
  	struct drm_map *request = data;
  	struct drm_local_map *map = NULL;
  	struct drm_map_list *r_list;
  	int ret;
  
  	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
  	    !drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	mutex_lock(&dev->struct_mutex);
  	list_for_each_entry(r_list, &dev->maplist, head) {
  		if (r_list->map &&
  		    r_list->user_token == (unsigned long)request->handle &&
  		    r_list->map->flags & _DRM_REMOVABLE) {
  			map = r_list->map;
  			break;
  		}
  	}
  
  	/* List has wrapped around to the head pointer, or its empty we didn't
  	 * find anything.
  	 */
  	if (list_empty(&dev->maplist) || !map) {
  		mutex_unlock(&dev->struct_mutex);
  		return -EINVAL;
  	}
  
  	/* Register and framebuffer maps are permanent */
  	if ((map->type == _DRM_REGISTERS) || (map->type == _DRM_FRAME_BUFFER)) {
  		mutex_unlock(&dev->struct_mutex);
  		return 0;
  	}
  
  	ret = drm_legacy_rmmap_locked(dev, map);
  
  	mutex_unlock(&dev->struct_mutex);
  
  	return ret;
  }
  
  /**
   * Cleanup after an error on one of the addbufs() functions.
   *
   * \param dev DRM device.
   * \param entry buffer entry where the error occurred.
   *
   * Frees any pages and buffers associated with the given entry.
   */
  static void drm_cleanup_buf_error(struct drm_device * dev,
  				  struct drm_buf_entry * entry)
  {
  	int i;
  
  	if (entry->seg_count) {
  		for (i = 0; i < entry->seg_count; i++) {
  			if (entry->seglist[i]) {
  				drm_pci_free(dev, entry->seglist[i]);
  			}
  		}
  		kfree(entry->seglist);
  
  		entry->seg_count = 0;
  	}
  
  	if (entry->buf_count) {
  		for (i = 0; i < entry->buf_count; i++) {
  			kfree(entry->buflist[i].dev_private);
  		}
  		kfree(entry->buflist);
  
  		entry->buf_count = 0;
  	}
  }
  
  #if IS_ENABLED(CONFIG_AGP)
  /**
   * Add AGP buffers for DMA transfers.
   *
   * \param dev struct drm_device to which the buffers are to be added.
   * \param request pointer to a struct drm_buf_desc describing the request.
   * \return zero on success or a negative number on failure.
   *
   * After some sanity checks creates a drm_buf structure for each buffer and
   * reallocates the buffer list of the same size order to accommodate the new
   * buffers.
   */
  int drm_legacy_addbufs_agp(struct drm_device *dev,
  			   struct drm_buf_desc *request)
  {
  	struct drm_device_dma *dma = dev->dma;
  	struct drm_buf_entry *entry;
  	struct drm_agp_mem *agp_entry;
  	struct drm_buf *buf;
  	unsigned long offset;
  	unsigned long agp_offset;
  	int count;
  	int order;
  	int size;
  	int alignment;
  	int page_order;
  	int total;
  	int byte_count;
  	int i, valid;
  	struct drm_buf **temp_buflist;
  
  	if (!dma)
  		return -EINVAL;
  
  	count = request->count;
  	order = order_base_2(request->size);
  	size = 1 << order;
  
  	alignment = (request->flags & _DRM_PAGE_ALIGN)
  	    ? PAGE_ALIGN(size) : size;
  	page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
  	total = PAGE_SIZE << page_order;
  
  	byte_count = 0;
  	agp_offset = dev->agp->base + request->agp_start;
  
  	DRM_DEBUG("count:      %d\n", count);
  	DRM_DEBUG("order:      %d\n", order);
  	DRM_DEBUG("size:       %d\n", size);
  	DRM_DEBUG("agp_offset: %lx\n", agp_offset);
  	DRM_DEBUG("alignment:  %d\n", alignment);
  	DRM_DEBUG("page_order: %d\n", page_order);
  	DRM_DEBUG("total:      %d\n", total);
  
  	if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
  		return -EINVAL;
  
  	/* Make sure buffers are located in AGP memory that we own */
  	valid = 0;
  	list_for_each_entry(agp_entry, &dev->agp->memory, head) {
  		if ((agp_offset >= agp_entry->bound) &&
  		    (agp_offset + total * count <= agp_entry->bound + agp_entry->pages * PAGE_SIZE)) {
  			valid = 1;
  			break;
  		}
  	}
  	if (!list_empty(&dev->agp->memory) && !valid) {
  		DRM_DEBUG("zone invalid\n");
  		return -EINVAL;
  	}
  	spin_lock(&dev->buf_lock);
  	if (dev->buf_use) {
  		spin_unlock(&dev->buf_lock);
  		return -EBUSY;
  	}
  	atomic_inc(&dev->buf_alloc);
  	spin_unlock(&dev->buf_lock);
  
  	mutex_lock(&dev->struct_mutex);
  	entry = &dma->bufs[order];
  	if (entry->buf_count) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;	/* May only call once for each order */
  	}
  
  	if (count < 0 || count > 4096) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -EINVAL;
  	}
  
  	entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL);
  	if (!entry->buflist) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  
  	entry->buf_size = size;
  	entry->page_order = page_order;
  
  	offset = 0;
  
  	while (entry->buf_count < count) {
  		buf = &entry->buflist[entry->buf_count];
  		buf->idx = dma->buf_count + entry->buf_count;
  		buf->total = alignment;
  		buf->order = order;
  		buf->used = 0;
  
  		buf->offset = (dma->byte_count + offset);
  		buf->bus_address = agp_offset + offset;
  		buf->address = (void *)(agp_offset + offset);
  		buf->next = NULL;
  		buf->waiting = 0;
  		buf->pending = 0;
  		buf->file_priv = NULL;
  
  		buf->dev_priv_size = dev->driver->dev_priv_size;
  		buf->dev_private = kzalloc(buf->dev_priv_size, GFP_KERNEL);
  		if (!buf->dev_private) {
  			/* Set count correctly so we free the proper amount. */
  			entry->buf_count = count;
  			drm_cleanup_buf_error(dev, entry);
  			mutex_unlock(&dev->struct_mutex);
  			atomic_dec(&dev->buf_alloc);
  			return -ENOMEM;
  		}
  
  		DRM_DEBUG("buffer %d @ %p\n", entry->buf_count, buf->address);
  
  		offset += alignment;
  		entry->buf_count++;
  		byte_count += PAGE_SIZE << page_order;
  	}
  
  	DRM_DEBUG("byte_count: %d\n", byte_count);
  
  	temp_buflist = krealloc(dma->buflist,
  				(dma->buf_count + entry->buf_count) *
  				sizeof(*dma->buflist), GFP_KERNEL);
  	if (!temp_buflist) {
  		/* Free the entry because it isn't valid */
  		drm_cleanup_buf_error(dev, entry);
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  	dma->buflist = temp_buflist;
  
  	for (i = 0; i < entry->buf_count; i++) {
  		dma->buflist[i + dma->buf_count] = &entry->buflist[i];
  	}
  
  	dma->buf_count += entry->buf_count;
  	dma->seg_count += entry->seg_count;
  	dma->page_count += byte_count >> PAGE_SHIFT;
  	dma->byte_count += byte_count;
  
  	DRM_DEBUG("dma->buf_count : %d\n", dma->buf_count);
  	DRM_DEBUG("entry->buf_count : %d\n", entry->buf_count);
  
  	mutex_unlock(&dev->struct_mutex);
  
  	request->count = entry->buf_count;
  	request->size = size;
  
  	dma->flags = _DRM_DMA_USE_AGP;
  
  	atomic_dec(&dev->buf_alloc);
  	return 0;
  }
  EXPORT_SYMBOL(drm_legacy_addbufs_agp);
  #endif /* CONFIG_AGP */
  
  int drm_legacy_addbufs_pci(struct drm_device *dev,
  			   struct drm_buf_desc *request)
  {
  	struct drm_device_dma *dma = dev->dma;
  	int count;
  	int order;
  	int size;
  	int total;
  	int page_order;
  	struct drm_buf_entry *entry;
  	drm_dma_handle_t *dmah;
  	struct drm_buf *buf;
  	int alignment;
  	unsigned long offset;
  	int i;
  	int byte_count;
  	int page_count;
  	unsigned long *temp_pagelist;
  	struct drm_buf **temp_buflist;
  
  	if (!drm_core_check_feature(dev, DRIVER_PCI_DMA))
  		return -EINVAL;
  
  	if (!dma)
  		return -EINVAL;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	count = request->count;
  	order = order_base_2(request->size);
  	size = 1 << order;
  
  	DRM_DEBUG("count=%d, size=%d (%d), order=%d\n",
  		  request->count, request->size, size, order);
  
  	if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
  		return -EINVAL;
  
  	alignment = (request->flags & _DRM_PAGE_ALIGN)
  	    ? PAGE_ALIGN(size) : size;
  	page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
  	total = PAGE_SIZE << page_order;
  
  	spin_lock(&dev->buf_lock);
  	if (dev->buf_use) {
  		spin_unlock(&dev->buf_lock);
  		return -EBUSY;
  	}
  	atomic_inc(&dev->buf_alloc);
  	spin_unlock(&dev->buf_lock);
  
  	mutex_lock(&dev->struct_mutex);
  	entry = &dma->bufs[order];
  	if (entry->buf_count) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;	/* May only call once for each order */
  	}
  
  	if (count < 0 || count > 4096) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -EINVAL;
  	}
  
  	entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL);
  	if (!entry->buflist) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  
  	entry->seglist = kcalloc(count, sizeof(*entry->seglist), GFP_KERNEL);
  	if (!entry->seglist) {
  		kfree(entry->buflist);
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  
  	/* Keep the original pagelist until we know all the allocations
  	 * have succeeded
  	 */
  	temp_pagelist = kmalloc_array(dma->page_count + (count << page_order),
  				      sizeof(*dma->pagelist),
  				      GFP_KERNEL);
  	if (!temp_pagelist) {
  		kfree(entry->buflist);
  		kfree(entry->seglist);
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  	memcpy(temp_pagelist,
  	       dma->pagelist, dma->page_count * sizeof(*dma->pagelist));
  	DRM_DEBUG("pagelist: %d entries\n",
  		  dma->page_count + (count << page_order));
  
  	entry->buf_size = size;
  	entry->page_order = page_order;
  	byte_count = 0;
  	page_count = 0;
  
  	while (entry->buf_count < count) {
  
  		dmah = drm_pci_alloc(dev, PAGE_SIZE << page_order, 0x1000);
  
  		if (!dmah) {
  			/* Set count correctly so we free the proper amount. */
  			entry->buf_count = count;
  			entry->seg_count = count;
  			drm_cleanup_buf_error(dev, entry);
  			kfree(temp_pagelist);
  			mutex_unlock(&dev->struct_mutex);
  			atomic_dec(&dev->buf_alloc);
  			return -ENOMEM;
  		}
  		entry->seglist[entry->seg_count++] = dmah;
  		for (i = 0; i < (1 << page_order); i++) {
  			DRM_DEBUG("page %d @ 0x%08lx\n",
  				  dma->page_count + page_count,
  				  (unsigned long)dmah->vaddr + PAGE_SIZE * i);
  			temp_pagelist[dma->page_count + page_count++]
  				= (unsigned long)dmah->vaddr + PAGE_SIZE * i;
  		}
  		for (offset = 0;
  		     offset + size <= total && entry->buf_count < count;
  		     offset += alignment, ++entry->buf_count) {
  			buf = &entry->buflist[entry->buf_count];
  			buf->idx = dma->buf_count + entry->buf_count;
  			buf->total = alignment;
  			buf->order = order;
  			buf->used = 0;
  			buf->offset = (dma->byte_count + byte_count + offset);
  			buf->address = (void *)(dmah->vaddr + offset);
  			buf->bus_address = dmah->busaddr + offset;
  			buf->next = NULL;
  			buf->waiting = 0;
  			buf->pending = 0;
  			buf->file_priv = NULL;
  
  			buf->dev_priv_size = dev->driver->dev_priv_size;
  			buf->dev_private = kzalloc(buf->dev_priv_size,
  						GFP_KERNEL);
  			if (!buf->dev_private) {
  				/* Set count correctly so we free the proper amount. */
  				entry->buf_count = count;
  				entry->seg_count = count;
  				drm_cleanup_buf_error(dev, entry);
  				kfree(temp_pagelist);
  				mutex_unlock(&dev->struct_mutex);
  				atomic_dec(&dev->buf_alloc);
  				return -ENOMEM;
  			}
  
  			DRM_DEBUG("buffer %d @ %p\n",
  				  entry->buf_count, buf->address);
  		}
  		byte_count += PAGE_SIZE << page_order;
  	}
  
  	temp_buflist = krealloc(dma->buflist,
  				(dma->buf_count + entry->buf_count) *
  				sizeof(*dma->buflist), GFP_KERNEL);
  	if (!temp_buflist) {
  		/* Free the entry because it isn't valid */
  		drm_cleanup_buf_error(dev, entry);
  		kfree(temp_pagelist);
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  	dma->buflist = temp_buflist;
  
  	for (i = 0; i < entry->buf_count; i++) {
  		dma->buflist[i + dma->buf_count] = &entry->buflist[i];
  	}
  
  	/* No allocations failed, so now we can replace the original pagelist
  	 * with the new one.
  	 */
  	if (dma->page_count) {
  		kfree(dma->pagelist);
  	}
  	dma->pagelist = temp_pagelist;
  
  	dma->buf_count += entry->buf_count;
  	dma->seg_count += entry->seg_count;
  	dma->page_count += entry->seg_count << page_order;
  	dma->byte_count += PAGE_SIZE * (entry->seg_count << page_order);
  
  	mutex_unlock(&dev->struct_mutex);
  
  	request->count = entry->buf_count;
  	request->size = size;
  
  	if (request->flags & _DRM_PCI_BUFFER_RO)
  		dma->flags = _DRM_DMA_USE_PCI_RO;
  
  	atomic_dec(&dev->buf_alloc);
  	return 0;
  
  }
  EXPORT_SYMBOL(drm_legacy_addbufs_pci);
  
  static int drm_legacy_addbufs_sg(struct drm_device *dev,
  				 struct drm_buf_desc *request)
  {
  	struct drm_device_dma *dma = dev->dma;
  	struct drm_buf_entry *entry;
  	struct drm_buf *buf;
  	unsigned long offset;
  	unsigned long agp_offset;
  	int count;
  	int order;
  	int size;
  	int alignment;
  	int page_order;
  	int total;
  	int byte_count;
  	int i;
  	struct drm_buf **temp_buflist;
  
  	if (!drm_core_check_feature(dev, DRIVER_SG))
  		return -EINVAL;
  
  	if (!dma)
  		return -EINVAL;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	count = request->count;
  	order = order_base_2(request->size);
  	size = 1 << order;
  
  	alignment = (request->flags & _DRM_PAGE_ALIGN)
  	    ? PAGE_ALIGN(size) : size;
  	page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
  	total = PAGE_SIZE << page_order;
  
  	byte_count = 0;
  	agp_offset = request->agp_start;
  
  	DRM_DEBUG("count:      %d\n", count);
  	DRM_DEBUG("order:      %d\n", order);
  	DRM_DEBUG("size:       %d\n", size);
  	DRM_DEBUG("agp_offset: %lu\n", agp_offset);
  	DRM_DEBUG("alignment:  %d\n", alignment);
  	DRM_DEBUG("page_order: %d\n", page_order);
  	DRM_DEBUG("total:      %d\n", total);
  
  	if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
  		return -EINVAL;
  
  	spin_lock(&dev->buf_lock);
  	if (dev->buf_use) {
  		spin_unlock(&dev->buf_lock);
  		return -EBUSY;
  	}
  	atomic_inc(&dev->buf_alloc);
  	spin_unlock(&dev->buf_lock);
  
  	mutex_lock(&dev->struct_mutex);
  	entry = &dma->bufs[order];
  	if (entry->buf_count) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;	/* May only call once for each order */
  	}
  
  	if (count < 0 || count > 4096) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -EINVAL;
  	}
  
  	entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL);
  	if (!entry->buflist) {
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  
  	entry->buf_size = size;
  	entry->page_order = page_order;
  
  	offset = 0;
  
  	while (entry->buf_count < count) {
  		buf = &entry->buflist[entry->buf_count];
  		buf->idx = dma->buf_count + entry->buf_count;
  		buf->total = alignment;
  		buf->order = order;
  		buf->used = 0;
  
  		buf->offset = (dma->byte_count + offset);
  		buf->bus_address = agp_offset + offset;
  		buf->address = (void *)(agp_offset + offset
  					+ (unsigned long)dev->sg->virtual);
  		buf->next = NULL;
  		buf->waiting = 0;
  		buf->pending = 0;
  		buf->file_priv = NULL;
  
  		buf->dev_priv_size = dev->driver->dev_priv_size;
  		buf->dev_private = kzalloc(buf->dev_priv_size, GFP_KERNEL);
  		if (!buf->dev_private) {
  			/* Set count correctly so we free the proper amount. */
  			entry->buf_count = count;
  			drm_cleanup_buf_error(dev, entry);
  			mutex_unlock(&dev->struct_mutex);
  			atomic_dec(&dev->buf_alloc);
  			return -ENOMEM;
  		}
  
  		DRM_DEBUG("buffer %d @ %p\n", entry->buf_count, buf->address);
  
  		offset += alignment;
  		entry->buf_count++;
  		byte_count += PAGE_SIZE << page_order;
  	}
  
  	DRM_DEBUG("byte_count: %d\n", byte_count);
  
  	temp_buflist = krealloc(dma->buflist,
  				(dma->buf_count + entry->buf_count) *
  				sizeof(*dma->buflist), GFP_KERNEL);
  	if (!temp_buflist) {
  		/* Free the entry because it isn't valid */
  		drm_cleanup_buf_error(dev, entry);
  		mutex_unlock(&dev->struct_mutex);
  		atomic_dec(&dev->buf_alloc);
  		return -ENOMEM;
  	}
  	dma->buflist = temp_buflist;
  
  	for (i = 0; i < entry->buf_count; i++) {
  		dma->buflist[i + dma->buf_count] = &entry->buflist[i];
  	}
  
  	dma->buf_count += entry->buf_count;
  	dma->seg_count += entry->seg_count;
  	dma->page_count += byte_count >> PAGE_SHIFT;
  	dma->byte_count += byte_count;
  
  	DRM_DEBUG("dma->buf_count : %d\n", dma->buf_count);
  	DRM_DEBUG("entry->buf_count : %d\n", entry->buf_count);
  
  	mutex_unlock(&dev->struct_mutex);
  
  	request->count = entry->buf_count;
  	request->size = size;
  
  	dma->flags = _DRM_DMA_USE_SG;
  
  	atomic_dec(&dev->buf_alloc);
  	return 0;
  }
  
  /**
   * Add buffers for DMA transfers (ioctl).
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg pointer to a struct drm_buf_desc request.
   * \return zero on success or a negative number on failure.
   *
   * According with the memory type specified in drm_buf_desc::flags and the
   * build options, it dispatches the call either to addbufs_agp(),
   * addbufs_sg() or addbufs_pci() for AGP, scatter-gather or consistent
   * PCI memory respectively.
   */
  int drm_legacy_addbufs(struct drm_device *dev, void *data,
  		       struct drm_file *file_priv)
  {
  	struct drm_buf_desc *request = data;
  	int ret;
  
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
  		return -EINVAL;
  
  #if IS_ENABLED(CONFIG_AGP)
  	if (request->flags & _DRM_AGP_BUFFER)
  		ret = drm_legacy_addbufs_agp(dev, request);
  	else
  #endif
  	if (request->flags & _DRM_SG_BUFFER)
  		ret = drm_legacy_addbufs_sg(dev, request);
  	else if (request->flags & _DRM_FB_BUFFER)
  		ret = -EINVAL;
  	else
  		ret = drm_legacy_addbufs_pci(dev, request);
  
  	return ret;
  }
  
  /**
   * Get information about the buffer mappings.
   *
   * This was originally mean for debugging purposes, or by a sophisticated
   * client library to determine how best to use the available buffers (e.g.,
   * large buffers can be used for image transfer).
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg pointer to a drm_buf_info structure.
   * \return zero on success or a negative number on failure.
   *
   * Increments drm_device::buf_use while holding the drm_device::buf_lock
   * lock, preventing of allocating more buffers after this call. Information
   * about each requested buffer is then copied into user space.
   */
  int __drm_legacy_infobufs(struct drm_device *dev,
  			void *data, int *p,
  			int (*f)(void *, int, struct drm_buf_entry *))
  {
  	struct drm_device_dma *dma = dev->dma;
  	int i;
  	int count;
  
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
  		return -EINVAL;
  
  	if (!dma)
  		return -EINVAL;
  
  	spin_lock(&dev->buf_lock);
  	if (atomic_read(&dev->buf_alloc)) {
  		spin_unlock(&dev->buf_lock);
  		return -EBUSY;
  	}
  	++dev->buf_use;		/* Can't allocate more after this call */
  	spin_unlock(&dev->buf_lock);
  
  	for (i = 0, count = 0; i < DRM_MAX_ORDER + 1; i++) {
  		if (dma->bufs[i].buf_count)
  			++count;
  	}
  
  	DRM_DEBUG("count = %d\n", count);
  
  	if (*p >= count) {
  		for (i = 0, count = 0; i < DRM_MAX_ORDER + 1; i++) {
  			struct drm_buf_entry *from = &dma->bufs[i];
  			if (from->buf_count) {
  				if (f(data, count, from) < 0)
  					return -EFAULT;
  				DRM_DEBUG("%d %d %d %d %d\n",
  					  i,
  					  dma->bufs[i].buf_count,
  					  dma->bufs[i].buf_size,
  					  dma->bufs[i].low_mark,
  					  dma->bufs[i].high_mark);
  				++count;
  			}
  		}
  	}
  	*p = count;
  
  	return 0;
  }
  
  static int copy_one_buf(void *data, int count, struct drm_buf_entry *from)
  {
  	struct drm_buf_info *request = data;
  	struct drm_buf_desc __user *to = &request->list[count];
  	struct drm_buf_desc v = {.count = from->buf_count,
  				 .size = from->buf_size,
  				 .low_mark = from->low_mark,
  				 .high_mark = from->high_mark};
  	return copy_to_user(to, &v, offsetof(struct drm_buf_desc, flags));
  }
  
  int drm_legacy_infobufs(struct drm_device *dev, void *data,
  			struct drm_file *file_priv)
  {
  	struct drm_buf_info *request = data;
  	return __drm_legacy_infobufs(dev, data, &request->count, copy_one_buf);
  }
  
  /**
   * Specifies a low and high water mark for buffer allocation
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg a pointer to a drm_buf_desc structure.
   * \return zero on success or a negative number on failure.
   *
   * Verifies that the size order is bounded between the admissible orders and
   * updates the respective drm_device_dma::bufs entry low and high water mark.
   *
   * \note This ioctl is deprecated and mostly never used.
   */
  int drm_legacy_markbufs(struct drm_device *dev, void *data,
  			struct drm_file *file_priv)
  {
  	struct drm_device_dma *dma = dev->dma;
  	struct drm_buf_desc *request = data;
  	int order;
  	struct drm_buf_entry *entry;
  
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
  		return -EINVAL;
  
  	if (!dma)
  		return -EINVAL;
  
  	DRM_DEBUG("%d, %d, %d\n",
  		  request->size, request->low_mark, request->high_mark);
  	order = order_base_2(request->size);
  	if (order < DRM_MIN_ORDER || order > DRM_MAX_ORDER)
  		return -EINVAL;
  	entry = &dma->bufs[order];
  
  	if (request->low_mark < 0 || request->low_mark > entry->buf_count)
  		return -EINVAL;
  	if (request->high_mark < 0 || request->high_mark > entry->buf_count)
  		return -EINVAL;
  
  	entry->low_mark = request->low_mark;
  	entry->high_mark = request->high_mark;
  
  	return 0;
  }
  
  /**
   * Unreserve the buffers in list, previously reserved using drmDMA.
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg pointer to a drm_buf_free structure.
   * \return zero on success or a negative number on failure.
   *
   * Calls free_buffer() for each used buffer.
   * This function is primarily used for debugging.
   */
  int drm_legacy_freebufs(struct drm_device *dev, void *data,
  			struct drm_file *file_priv)
  {
  	struct drm_device_dma *dma = dev->dma;
  	struct drm_buf_free *request = data;
  	int i;
  	int idx;
  	struct drm_buf *buf;
  
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
  		return -EINVAL;
  
  	if (!dma)
  		return -EINVAL;
  
  	DRM_DEBUG("%d\n", request->count);
  	for (i = 0; i < request->count; i++) {
  		if (copy_from_user(&idx, &request->list[i], sizeof(idx)))
  			return -EFAULT;
  		if (idx < 0 || idx >= dma->buf_count) {
  			DRM_ERROR("Index %d (of %d max)\n",
  				  idx, dma->buf_count - 1);
  			return -EINVAL;
  		}
  		idx = array_index_nospec(idx, dma->buf_count);
  		buf = dma->buflist[idx];
  		if (buf->file_priv != file_priv) {
  			DRM_ERROR("Process %d freeing buffer not owned\n",
  				  task_pid_nr(current));
  			return -EINVAL;
  		}
  		drm_legacy_free_buffer(dev, buf);
  	}
  
  	return 0;
  }
  
  /**
   * Maps all of the DMA buffers into client-virtual space (ioctl).
   *
   * \param inode device inode.
   * \param file_priv DRM file private.
   * \param cmd command.
   * \param arg pointer to a drm_buf_map structure.
   * \return zero on success or a negative number on failure.
   *
   * Maps the AGP, SG or PCI buffer region with vm_mmap(), and copies information
   * about each buffer into user space. For PCI buffers, it calls vm_mmap() with
   * offset equal to 0, which drm_mmap() interpretes as PCI buffers and calls
   * drm_mmap_dma().
   */
  int __drm_legacy_mapbufs(struct drm_device *dev, void *data, int *p,
  			 void __user **v,
  			 int (*f)(void *, int, unsigned long,
  				  struct drm_buf *),
  		         struct drm_file *file_priv)
  {
  	struct drm_device_dma *dma = dev->dma;
  	int retcode = 0;
  	unsigned long virtual;
  	int i;
  
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA))
  		return -EINVAL;
  
  	if (!dma)
  		return -EINVAL;
  
  	spin_lock(&dev->buf_lock);
  	if (atomic_read(&dev->buf_alloc)) {
  		spin_unlock(&dev->buf_lock);
  		return -EBUSY;
  	}
  	dev->buf_use++;		/* Can't allocate more after this call */
  	spin_unlock(&dev->buf_lock);
  
  	if (*p >= dma->buf_count) {
  		if ((dev->agp && (dma->flags & _DRM_DMA_USE_AGP))
  		    || (drm_core_check_feature(dev, DRIVER_SG)
  			&& (dma->flags & _DRM_DMA_USE_SG))) {
  			struct drm_local_map *map = dev->agp_buffer_map;
  			unsigned long token = dev->agp_buffer_token;
  
  			if (!map) {
  				retcode = -EINVAL;
  				goto done;
  			}
  			virtual = vm_mmap(file_priv->filp, 0, map->size,
  					  PROT_READ | PROT_WRITE,
  					  MAP_SHARED,
  					  token);
  		} else {
  			virtual = vm_mmap(file_priv->filp, 0, dma->byte_count,
  					  PROT_READ | PROT_WRITE,
  					  MAP_SHARED, 0);
  		}
  		if (virtual > -1024UL) {
  			/* Real error */
  			retcode = (signed long)virtual;
  			goto done;
  		}
  		*v = (void __user *)virtual;
  
  		for (i = 0; i < dma->buf_count; i++) {
  			if (f(data, i, virtual, dma->buflist[i]) < 0) {
  				retcode = -EFAULT;
  				goto done;
  			}
  		}
  	}
        done:
  	*p = dma->buf_count;
  	DRM_DEBUG("%d buffers, retcode = %d\n", *p, retcode);
  
  	return retcode;
  }
  
  static int map_one_buf(void *data, int idx, unsigned long virtual,
  			struct drm_buf *buf)
  {
  	struct drm_buf_map *request = data;
  	unsigned long address = virtual + buf->offset;	/* *** */
  
  	if (copy_to_user(&request->list[idx].idx, &buf->idx,
  			 sizeof(request->list[0].idx)))
  		return -EFAULT;
  	if (copy_to_user(&request->list[idx].total, &buf->total,
  			 sizeof(request->list[0].total)))
  		return -EFAULT;
  	if (clear_user(&request->list[idx].used, sizeof(int)))
  		return -EFAULT;
  	if (copy_to_user(&request->list[idx].address, &address,
  			 sizeof(address)))
  		return -EFAULT;
  	return 0;
  }
  
  int drm_legacy_mapbufs(struct drm_device *dev, void *data,
  		       struct drm_file *file_priv)
  {
  	struct drm_buf_map *request = data;
  	return __drm_legacy_mapbufs(dev, data, &request->count,
  				    &request->virtual, map_one_buf,
  				    file_priv);
  }
  
  int drm_legacy_dma_ioctl(struct drm_device *dev, void *data,
  		  struct drm_file *file_priv)
  {
  	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
  		return -EINVAL;
  
  	if (dev->driver->dma_ioctl)
  		return dev->driver->dma_ioctl(dev, data, file_priv);
  	else
  		return -EINVAL;
  }
  
  struct drm_local_map *drm_legacy_getsarea(struct drm_device *dev)
  {
  	struct drm_map_list *entry;
  
  	list_for_each_entry(entry, &dev->maplist, head) {
  		if (entry->map && entry->map->type == _DRM_SHM &&
  		    (entry->map->flags & _DRM_CONTAINS_LOCK)) {
  			return entry->map;
  		}
  	}
  	return NULL;
  }
  EXPORT_SYMBOL(drm_legacy_getsarea);
  