0,0 → 1,436 |
/* |
* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA |
* Copyright (c) 2012 David Airlie <airlied@linux.ie> |
* 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/drmP.h> |
#include <drm/drm_mm.h> |
#include <drm/drm_vma_manager.h> |
//#include <linux/fs.h> |
#include <linux/mm.h> |
#include <linux/module.h> |
#include <linux/rbtree.h> |
#include <linux/slab.h> |
#include <linux/spinlock.h> |
#include <linux/types.h> |
|
/** |
* DOC: vma offset manager |
* |
* The vma-manager is responsible to map arbitrary driver-dependent memory |
* regions into the linear user address-space. It provides offsets to the |
* caller which can then be used on the address_space of the drm-device. It |
* takes care to not overlap regions, size them appropriately and to not |
* confuse mm-core by inconsistent fake vm_pgoff fields. |
* Drivers shouldn't use this for object placement in VMEM. This manager should |
* only be used to manage mappings into linear user-space VMs. |
* |
* We use drm_mm as backend to manage object allocations. But it is highly |
* optimized for alloc/free calls, not lookups. Hence, we use an rb-tree to |
* speed up offset lookups. |
* |
* You must not use multiple offset managers on a single address_space. |
* Otherwise, mm-core will be unable to tear down memory mappings as the VM will |
* no longer be linear. Please use VM_NONLINEAR in that case and implement your |
* own offset managers. |
* |
* This offset manager works on page-based addresses. That is, every argument |
* and return code (with the exception of drm_vma_node_offset_addr()) is given |
* in number of pages, not number of bytes. That means, object sizes and offsets |
* must always be page-aligned (as usual). |
* If you want to get a valid byte-based user-space address for a given offset, |
* please see drm_vma_node_offset_addr(). |
* |
* Additionally to offset management, the vma offset manager also handles access |
* management. For every open-file context that is allowed to access a given |
* node, you must call drm_vma_node_allow(). Otherwise, an mmap() call on this |
* open-file with the offset of the node will fail with -EACCES. To revoke |
* access again, use drm_vma_node_revoke(). However, the caller is responsible |
* for destroying already existing mappings, if required. |
*/ |
|
/** |
* drm_vma_offset_manager_init - Initialize new offset-manager |
* @mgr: Manager object |
* @page_offset: Offset of available memory area (page-based) |
* @size: Size of available address space range (page-based) |
* |
* Initialize a new offset-manager. The offset and area size available for the |
* manager are given as @page_offset and @size. Both are interpreted as |
* page-numbers, not bytes. |
* |
* Adding/removing nodes from the manager is locked internally and protected |
* against concurrent access. However, node allocation and destruction is left |
* for the caller. While calling into the vma-manager, a given node must |
* always be guaranteed to be referenced. |
*/ |
void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr, |
unsigned long page_offset, unsigned long size) |
{ |
rwlock_init(&mgr->vm_lock); |
mgr->vm_addr_space_rb = RB_ROOT; |
drm_mm_init(&mgr->vm_addr_space_mm, page_offset, size); |
} |
EXPORT_SYMBOL(drm_vma_offset_manager_init); |
|
/** |
* drm_vma_offset_manager_destroy() - Destroy offset manager |
* @mgr: Manager object |
* |
* Destroy an object manager which was previously created via |
* drm_vma_offset_manager_init(). The caller must remove all allocated nodes |
* before destroying the manager. Otherwise, drm_mm will refuse to free the |
* requested resources. |
* |
* The manager must not be accessed after this function is called. |
*/ |
void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr) |
{ |
/* take the lock to protect against buggy drivers */ |
write_lock(&mgr->vm_lock); |
drm_mm_takedown(&mgr->vm_addr_space_mm); |
write_unlock(&mgr->vm_lock); |
} |
EXPORT_SYMBOL(drm_vma_offset_manager_destroy); |
|
/** |
* drm_vma_offset_lookup() - Find node in offset space |
* @mgr: Manager object |
* @start: Start address for object (page-based) |
* @pages: Size of object (page-based) |
* |
* Find a node given a start address and object size. This returns the _best_ |
* match for the given node. That is, @start may point somewhere into a valid |
* region and the given node will be returned, as long as the node spans the |
* whole requested area (given the size in number of pages as @pages). |
* |
* RETURNS: |
* Returns NULL if no suitable node can be found. Otherwise, the best match |
* is returned. It's the caller's responsibility to make sure the node doesn't |
* get destroyed before the caller can access it. |
*/ |
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 *node; |
|
read_lock(&mgr->vm_lock); |
node = drm_vma_offset_lookup_locked(mgr, start, pages); |
read_unlock(&mgr->vm_lock); |
|
return node; |
} |
EXPORT_SYMBOL(drm_vma_offset_lookup); |
|
/** |
* drm_vma_offset_lookup_locked() - Find node in offset space |
* @mgr: Manager object |
* @start: Start address for object (page-based) |
* @pages: Size of object (page-based) |
* |
* Same as drm_vma_offset_lookup() but requires the caller to lock offset lookup |
* manually. See drm_vma_offset_lock_lookup() for an example. |
* |
* RETURNS: |
* Returns NULL if no suitable node can be found. Otherwise, the best match |
* is returned. |
*/ |
struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr, |
unsigned long start, |
unsigned long pages) |
{ |
struct drm_vma_offset_node *node, *best; |
struct rb_node *iter; |
unsigned long offset; |
|
iter = mgr->vm_addr_space_rb.rb_node; |
best = NULL; |
|
while (likely(iter)) { |
node = rb_entry(iter, struct drm_vma_offset_node, vm_rb); |
offset = node->vm_node.start; |
if (start >= offset) { |
iter = iter->rb_right; |
best = node; |
if (start == offset) |
break; |
} else { |
iter = iter->rb_left; |
} |
} |
|
/* verify that the node spans the requested area */ |
if (best) { |
offset = best->vm_node.start + best->vm_node.size; |
if (offset < start + pages) |
best = NULL; |
} |
|
return best; |
} |
EXPORT_SYMBOL(drm_vma_offset_lookup_locked); |
|
/* internal helper to link @node into the rb-tree */ |
static void _drm_vma_offset_add_rb(struct drm_vma_offset_manager *mgr, |
struct drm_vma_offset_node *node) |
{ |
struct rb_node **iter = &mgr->vm_addr_space_rb.rb_node; |
struct rb_node *parent = NULL; |
struct drm_vma_offset_node *iter_node; |
|
while (likely(*iter)) { |
parent = *iter; |
iter_node = rb_entry(*iter, struct drm_vma_offset_node, vm_rb); |
|
if (node->vm_node.start < iter_node->vm_node.start) |
iter = &(*iter)->rb_left; |
else if (node->vm_node.start > iter_node->vm_node.start) |
iter = &(*iter)->rb_right; |
else |
BUG(); |
} |
|
rb_link_node(&node->vm_rb, parent, iter); |
rb_insert_color(&node->vm_rb, &mgr->vm_addr_space_rb); |
} |
|
/** |
* drm_vma_offset_add() - Add offset node to manager |
* @mgr: Manager object |
* @node: Node to be added |
* @pages: Allocation size visible to user-space (in number of pages) |
* |
* Add a node to the offset-manager. If the node was already added, this does |
* nothing and return 0. @pages is the size of the object given in number of |
* pages. |
* After this call succeeds, you can access the offset of the node until it |
* is removed again. |
* |
* If this call fails, it is safe to retry the operation or call |
* drm_vma_offset_remove(), anyway. However, no cleanup is required in that |
* case. |
* |
* @pages is not required to be the same size as the underlying memory object |
* that you want to map. It only limits the size that user-space can map into |
* their address space. |
* |
* RETURNS: |
* 0 on success, negative error code on failure. |
*/ |
int drm_vma_offset_add(struct drm_vma_offset_manager *mgr, |
struct drm_vma_offset_node *node, unsigned long pages) |
{ |
int ret; |
|
write_lock(&mgr->vm_lock); |
|
if (drm_mm_node_allocated(&node->vm_node)) { |
ret = 0; |
goto out_unlock; |
} |
|
ret = drm_mm_insert_node(&mgr->vm_addr_space_mm, &node->vm_node, |
pages, 0, DRM_MM_SEARCH_DEFAULT); |
if (ret) |
goto out_unlock; |
|
_drm_vma_offset_add_rb(mgr, node); |
|
out_unlock: |
write_unlock(&mgr->vm_lock); |
return ret; |
} |
EXPORT_SYMBOL(drm_vma_offset_add); |
|
/** |
* drm_vma_offset_remove() - Remove offset node from manager |
* @mgr: Manager object |
* @node: Node to be removed |
* |
* Remove a node from the offset manager. If the node wasn't added before, this |
* does nothing. After this call returns, the offset and size will be 0 until a |
* new offset is allocated via drm_vma_offset_add() again. Helper functions like |
* drm_vma_node_start() and drm_vma_node_offset_addr() will return 0 if no |
* offset is allocated. |
*/ |
void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr, |
struct drm_vma_offset_node *node) |
{ |
write_lock(&mgr->vm_lock); |
|
if (drm_mm_node_allocated(&node->vm_node)) { |
rb_erase(&node->vm_rb, &mgr->vm_addr_space_rb); |
drm_mm_remove_node(&node->vm_node); |
memset(&node->vm_node, 0, sizeof(node->vm_node)); |
} |
|
write_unlock(&mgr->vm_lock); |
} |
EXPORT_SYMBOL(drm_vma_offset_remove); |
|
/** |
* drm_vma_node_allow - Add open-file to list of allowed users |
* @node: Node to modify |
* @filp: Open file to add |
* |
* Add @filp to the list of allowed open-files for this node. If @filp is |
* already on this list, the ref-count is incremented. |
* |
* The list of allowed-users is preserved across drm_vma_offset_add() and |
* drm_vma_offset_remove() calls. You may even call it if the node is currently |
* not added to any offset-manager. |
* |
* You must remove all open-files the same number of times as you added them |
* before destroying the node. Otherwise, you will leak memory. |
* |
* This is locked against concurrent access internally. |
* |
* RETURNS: |
* 0 on success, negative error code on internal failure (out-of-mem) |
*/ |
int drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *filp) |
{ |
struct rb_node **iter; |
struct rb_node *parent = NULL; |
struct drm_vma_offset_file *new, *entry; |
int ret = 0; |
|
/* Preallocate entry to avoid atomic allocations below. It is quite |
* unlikely that an open-file is added twice to a single node so we |
* don't optimize for this case. OOM is checked below only if the entry |
* is actually used. */ |
new = kmalloc(sizeof(*entry), GFP_KERNEL); |
|
write_lock(&node->vm_lock); |
|
iter = &node->vm_files.rb_node; |
|
while (likely(*iter)) { |
parent = *iter; |
entry = rb_entry(*iter, struct drm_vma_offset_file, vm_rb); |
|
if (filp == entry->vm_filp) { |
entry->vm_count++; |
goto unlock; |
} else if (filp > entry->vm_filp) { |
iter = &(*iter)->rb_right; |
} else { |
iter = &(*iter)->rb_left; |
} |
} |
|
if (!new) { |
ret = -ENOMEM; |
goto unlock; |
} |
|
new->vm_filp = filp; |
new->vm_count = 1; |
rb_link_node(&new->vm_rb, parent, iter); |
rb_insert_color(&new->vm_rb, &node->vm_files); |
new = NULL; |
|
unlock: |
write_unlock(&node->vm_lock); |
kfree(new); |
return ret; |
} |
EXPORT_SYMBOL(drm_vma_node_allow); |
|
/** |
* drm_vma_node_revoke - Remove open-file from list of allowed users |
* @node: Node to modify |
* @filp: Open file to remove |
* |
* Decrement the ref-count of @filp in the list of allowed open-files on @node. |
* If the ref-count drops to zero, remove @filp from the list. You must call |
* this once for every drm_vma_node_allow() on @filp. |
* |
* This is locked against concurrent access internally. |
* |
* If @filp is not on the list, nothing is done. |
*/ |
void drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *filp) |
{ |
struct drm_vma_offset_file *entry; |
struct rb_node *iter; |
|
write_lock(&node->vm_lock); |
|
iter = node->vm_files.rb_node; |
while (likely(iter)) { |
entry = rb_entry(iter, struct drm_vma_offset_file, vm_rb); |
if (filp == entry->vm_filp) { |
if (!--entry->vm_count) { |
rb_erase(&entry->vm_rb, &node->vm_files); |
kfree(entry); |
} |
break; |
} else if (filp > entry->vm_filp) { |
iter = iter->rb_right; |
} else { |
iter = iter->rb_left; |
} |
} |
|
write_unlock(&node->vm_lock); |
} |
EXPORT_SYMBOL(drm_vma_node_revoke); |
|
/** |
* drm_vma_node_is_allowed - Check whether an open-file is granted access |
* @node: Node to check |
* @filp: Open-file to check for |
* |
* Search the list in @node whether @filp is currently on the list of allowed |
* open-files (see drm_vma_node_allow()). |
* |
* This is locked against concurrent access internally. |
* |
* RETURNS: |
* true iff @filp is on the list |
*/ |
bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node, |
struct file *filp) |
{ |
struct drm_vma_offset_file *entry; |
struct rb_node *iter; |
|
read_lock(&node->vm_lock); |
|
iter = node->vm_files.rb_node; |
while (likely(iter)) { |
entry = rb_entry(iter, struct drm_vma_offset_file, vm_rb); |
if (filp == entry->vm_filp) |
break; |
else if (filp > entry->vm_filp) |
iter = iter->rb_right; |
else |
iter = iter->rb_left; |
} |
|
read_unlock(&node->vm_lock); |
|
return iter; |
} |
EXPORT_SYMBOL(drm_vma_node_is_allowed); |