#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>
* 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.
*/
/**
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);
*/
#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 {
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
* 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 if @node isn't
- * already cleared (eg., via kzalloc) before using it with any VMA offset
- * manager.
+ * 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_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__ */
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff