include/drm/drm_vma_manager.h - maze/linux - Git at Google

 #ifndef __DRM_VMA_MANAGER_H__
 #define __DRM_VMA_MANAGER_H__

 /*
  * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.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 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
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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/drm_mm.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/rbtree.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>

 struct drm_vma_offset_file {
 	struct rb_node vm_rb;
 	struct file *vm_filp;
 	unsigned long vm_count;
 };

 struct drm_vma_offset_node {
 	rwlock_t vm_lock;
 	struct drm_mm_node vm_node;
 	struct rb_node vm_rb;
 	struct rb_root vm_files;
 };

 struct drm_vma_offset_manager {
 	rwlock_t vm_lock;
 	struct rb_root vm_addr_space_rb;
 	struct drm_mm vm_addr_space_mm;
 };

 void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
 				 unsigned long page_offset, unsigned long size);
 void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);

 struct drm_vma_offset_node *drm_vma_offset_lookup(struct drm_vma_offset_manager *mgr,
 						  unsigned long start,
 						  unsigned long pages);
 struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
 							   unsigned long start,
 							   unsigned long pages);
 int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
 		       struct drm_vma_offset_node *node, unsigned long pages);
 void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
 			   struct drm_vma_offset_node *node);

 int drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *filp);
 void drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *filp);
 bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
 			     struct file *filp);

 /**
  * drm_vma_offset_exact_lookup() - Look up node by exact address
  * @mgr: Manager object
  * @start: Start address (page-based, not byte-based)
  * @pages: Size of object (page-based)
  *
  * Same as drm_vma_offset_lookup() but does not allow any offset into the node.
  * It only returns the exact object with the given start address.
  *
  * RETURNS:
  * Node at exact start address @start.
  */
 static inline struct drm_vma_offset_node *
 drm_vma_offset_exact_lookup(struct drm_vma_offset_manager *mgr,
 			    unsigned long start,
 			    unsigned long pages)
 {
 	struct drm_vma_offset_node *node;

 	node = drm_vma_offset_lookup(mgr, start, pages);
 	return (node && node->vm_node.start == start) ? node : NULL;
 }

 /**
  * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
  * @mgr: Manager object
  *
  * Lock VMA manager for extended lookups. Only *_locked() VMA function calls
  * are allowed while holding this lock. All other contexts are blocked from VMA
  * until the lock is released via drm_vma_offset_unlock_lookup().
  *
  * Use this if you need to take a reference to the objects returned by
  * drm_vma_offset_lookup_locked() before releasing this lock again.
  *
  * This lock must not be used for anything else than extended lookups. You must
  * not call any other VMA helpers while holding this lock.
  *
  * Note: You're in atomic-context while holding this lock!
  *
  * Example:
  *   drm_vma_offset_lock_lookup(mgr);
  *   node = drm_vma_offset_lookup_locked(mgr);
  *   if (node)
  *       kref_get_unless_zero(container_of(node, sth, entr));
  *   drm_vma_offset_unlock_lookup(mgr);
  */
 static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
 {
 	read_lock(&mgr->vm_lock);
 }

 /**
  * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
  * @mgr: Manager object
  *
  * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
  */
 static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
 {
 	read_unlock(&mgr->vm_lock);
 }

 /**
  * drm_vma_node_reset() - Initialize or reset node object
  * @node: Node to initialize or reset
  *
  * Reset a node to its initial state. This must be called before using it with
  * any VMA offset manager.
  *
  * This must not be called on an already allocated node, or you will leak
  * memory.
  */
 static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
 {
 	memset(node, 0, sizeof(*node));
 	node->vm_files = RB_ROOT;
 	rwlock_init(&node->vm_lock);
 }

 /**
  * drm_vma_node_start() - Return start address for page-based addressing
  * @node: Node to inspect
  *
  * Return the start address of the given node. This can be used as offset into
  * the linear VM space that is provided by the VMA offset manager. Note that
  * this can only be used for page-based addressing. If you need a proper offset
  * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
  * drm_vma_node_offset_addr() helper instead.
  *
  * RETURNS:
  * Start address of @node for page-based addressing. 0 if the node does not
  * have an offset allocated.
  */
 static inline unsigned long drm_vma_node_start(struct drm_vma_offset_node *node)
 {
 	return node->vm_node.start;
 }

 /**
  * drm_vma_node_size() - Return size (page-based)
  * @node: Node to inspect
  *
  * Return the size as number of pages for the given node. This is the same size
  * that was passed to drm_vma_offset_add(). If no offset is allocated for the
  * node, this is 0.
  *
  * RETURNS:
  * Size of @node as number of pages. 0 if the node does not have an offset
  * allocated.
  */
 static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
 {
 	return node->vm_node.size;
 }

 /**
  * drm_vma_node_has_offset() - Check whether node is added to offset manager
  * @node: Node to be checked
  *
  * RETURNS:
  * true iff the node was previously allocated an offset and added to
  * an vma offset manager.
  */
 static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
 {
 	return drm_mm_node_allocated(&node->vm_node);
 }

 /**
  * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
  * @node: Linked offset node
  *
  * Same as drm_vma_node_start() but returns the address as a valid offset that
  * can be used for user-space mappings during mmap().
  * This must not be called on unlinked nodes.
  *
  * RETURNS:
  * Offset of @node for byte-based addressing. 0 if the node does not have an
  * object allocated.
  */
 static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
 {
 	return ((__u64)node->vm_node.start) << PAGE_SHIFT;
 }

 /**
  * drm_vma_node_unmap() - Unmap offset node
  * @node: Offset node
  * @file_mapping: Address space to unmap @node from
  *
  * Unmap all userspace mappings for a given offset node. The mappings must be
  * associated with the @file_mapping address-space. If no offset exists
  * nothing is done.
  *
  * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
  * is not called on this node concurrently.
  */
 static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
 				      struct address_space *file_mapping)
 {
 	if (drm_vma_node_has_offset(node))
 		unmap_mapping_range(file_mapping,
 				    drm_vma_node_offset_addr(node),
 				    drm_vma_node_size(node) << PAGE_SHIFT, 1);
 }

 /**
  * drm_vma_node_verify_access() - Access verification helper for TTM
  * @node: Offset node
  * @filp: Open-file
  *
  * This checks whether @filp is granted access to @node. It is the same as
  * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
  * verify_access() callbacks.
  *
  * RETURNS:
  * 0 if access is granted, -EACCES otherwise.
  */
 static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
 					     struct file *filp)
 {
 	return drm_vma_node_is_allowed(node, filp) ? 0 : -EACCES;
 }

 #endif /* __DRM_VMA_MANAGER_H__ */
	#ifndef __DRM_VMA_MANAGER_H__
	#define __DRM_VMA_MANAGER_H__

	/*
	* Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.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 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
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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/drm_mm.h>
	#include <linux/fs.h>
	#include <linux/mm.h>
	#include <linux/module.h>
	#include <linux/rbtree.h>
	#include <linux/spinlock.h>
	#include <linux/types.h>

	struct drm_vma_offset_file {
	struct rb_node vm_rb;
	struct file *vm_filp;
	unsigned long vm_count;
	};

	struct drm_vma_offset_node {
	rwlock_t vm_lock;
	struct drm_mm_node vm_node;
	struct rb_node vm_rb;
	struct rb_root vm_files;
	};

	struct drm_vma_offset_manager {
	rwlock_t vm_lock;
	struct rb_root vm_addr_space_rb;
	struct drm_mm vm_addr_space_mm;
	};

	void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
	unsigned long page_offset, unsigned long size);
	void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);

	struct drm_vma_offset_node drm_vma_offset_lookup(struct drm_vma_offset_manager mgr,
	unsigned long start,
	unsigned long pages);
	struct drm_vma_offset_node drm_vma_offset_lookup_locked(struct drm_vma_offset_manager mgr,
	unsigned long start,
	unsigned long pages);
	int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
	struct drm_vma_offset_node *node, unsigned long pages);
	void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
	struct drm_vma_offset_node *node);

	int drm_vma_node_allow(struct drm_vma_offset_node node, struct file filp);
	void drm_vma_node_revoke(struct drm_vma_offset_node node, struct file filp);
	bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
	struct file *filp);

	/**
	* drm_vma_offset_exact_lookup() - Look up node by exact address
	* @mgr: Manager object
	* @start: Start address (page-based, not byte-based)
	* @pages: Size of object (page-based)
	*
	* Same as drm_vma_offset_lookup() but does not allow any offset into the node.
	* It only returns the exact object with the given start address.
	*
	* RETURNS:
	* Node at exact start address @start.
	*/
	static inline struct drm_vma_offset_node *
	drm_vma_offset_exact_lookup(struct drm_vma_offset_manager *mgr,
	unsigned long start,
	unsigned long pages)
	{
	struct drm_vma_offset_node *node;

	node = drm_vma_offset_lookup(mgr, start, pages);
	return (node && node->vm_node.start == start) ? node : NULL;
	}

	/**
	* drm_vma_offset_lock_lookup() - Lock lookup for extended private use
	* @mgr: Manager object
	*
	* Lock VMA manager for extended lookups. Only *_locked() VMA function calls
	* are allowed while holding this lock. All other contexts are blocked from VMA
	* until the lock is released via drm_vma_offset_unlock_lookup().
	*
	* Use this if you need to take a reference to the objects returned by
	* drm_vma_offset_lookup_locked() before releasing this lock again.
	*
	* This lock must not be used for anything else than extended lookups. You must
	* not call any other VMA helpers while holding this lock.
	*
	* Note: You're in atomic-context while holding this lock!
	*
	* Example:
	* drm_vma_offset_lock_lookup(mgr);
	* node = drm_vma_offset_lookup_locked(mgr);
	* if (node)
	* kref_get_unless_zero(container_of(node, sth, entr));
	* drm_vma_offset_unlock_lookup(mgr);
	*/
	static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
	{
	read_lock(&mgr->vm_lock);
	}

	/**
	* drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
	* @mgr: Manager object
	*
	* Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
	*/
	static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
	{
	read_unlock(&mgr->vm_lock);
	}

	/**
	* drm_vma_node_reset() - Initialize or reset node object
	* @node: Node to initialize or reset
	*
	* Reset a node to its initial state. This must be called before using it with
	* any VMA offset manager.
	*
	* This must not be called on an already allocated node, or you will leak
	* memory.
	*/
	static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
	{
	memset(node, 0, sizeof(*node));
	node->vm_files = RB_ROOT;
	rwlock_init(&node->vm_lock);
	}

	/**
	* drm_vma_node_start() - Return start address for page-based addressing
	* @node: Node to inspect
	*
	* Return the start address of the given node. This can be used as offset into
	* the linear VM space that is provided by the VMA offset manager. Note that
	* this can only be used for page-based addressing. If you need a proper offset
	* for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
	* drm_vma_node_offset_addr() helper instead.
	*
	* RETURNS:
	* Start address of @node for page-based addressing. 0 if the node does not
	* have an offset allocated.
	*/
	static inline unsigned long drm_vma_node_start(struct drm_vma_offset_node *node)
	{
	return node->vm_node.start;
	}

	/**
	* drm_vma_node_size() - Return size (page-based)
	* @node: Node to inspect
	*
	* Return the size as number of pages for the given node. This is the same size
	* that was passed to drm_vma_offset_add(). If no offset is allocated for the
	* node, this is 0.
	*
	* RETURNS:
	* Size of @node as number of pages. 0 if the node does not have an offset
	* allocated.
	*/
	static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
	{
	return node->vm_node.size;
	}

	/**
	* drm_vma_node_has_offset() - Check whether node is added to offset manager
	* @node: Node to be checked
	*
	* RETURNS:
	* true iff the node was previously allocated an offset and added to
	* an vma offset manager.
	*/
	static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
	{
	return drm_mm_node_allocated(&node->vm_node);
	}

	/**
	* drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
	* @node: Linked offset node
	*
	* Same as drm_vma_node_start() but returns the address as a valid offset that
	* can be used for user-space mappings during mmap().
	* This must not be called on unlinked nodes.
	*
	* RETURNS:
	* Offset of @node for byte-based addressing. 0 if the node does not have an
	* object allocated.
	*/
	static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
	{
	return ((__u64)node->vm_node.start) << PAGE_SHIFT;
	}

	/**
	* drm_vma_node_unmap() - Unmap offset node
	* @node: Offset node
	* @file_mapping: Address space to unmap @node from
	*
	* Unmap all userspace mappings for a given offset node. The mappings must be
	* associated with the @file_mapping address-space. If no offset exists
	* nothing is done.
	*
	* This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
	* is not called on this node concurrently.
	*/
	static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
	struct address_space *file_mapping)
	{
	if (drm_vma_node_has_offset(node))
	unmap_mapping_range(file_mapping,
	drm_vma_node_offset_addr(node),
	drm_vma_node_size(node) << PAGE_SHIFT, 1);
	}

	/**
	* drm_vma_node_verify_access() - Access verification helper for TTM
	* @node: Offset node
	* @filp: Open-file
	*
	* This checks whether @filp is granted access to @node. It is the same as
	* drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
	* verify_access() callbacks.
	*
	* RETURNS:
	* 0 if access is granted, -EACCES otherwise.
	*/
	static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
	struct file *filp)
	{
	return drm_vma_node_is_allowed(node, filp) ? 0 : -EACCES;
	}

	#endif /* __DRM_VMA_MANAGER_H__ */