/**************************************************************************
*
* Copyright (c) 2009-2013 VMware, Inc., Palo Alto, CA., USA
* 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS 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.
*
**************************************************************************/
/*
* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*
* While no substantial code is shared, the prime code is inspired by
* drm_prime.c, with
* Authors:
* Dave Airlie <airlied@redhat.com>
* Rob Clark <rob.clark@linaro.org>
*/
/** @file ttm_ref_object.c
*
* Base- and reference object implementation for the various
* ttm objects. Implements reference counting, minimal security checks
* and release on file close.
*/
/**
* struct ttm_object_file
*
* @tdev: Pointer to the ttm_object_device.
*
* @lock: Lock that protects the ref_list list and the
* ref_hash hash tables.
*
* @ref_list: List of ttm_ref_objects to be destroyed at
* file release.
*
* @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
* for fast lookup of ref objects given a base object.
*/
#define pr_fmt(fmt) "[TTM] " fmt
#include <drm/ttm/ttm_object.h>
#include <drm/ttm/ttm_module.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/atomic.h>
struct ttm_object_file {
struct ttm_object_device *tdev;
spinlock_t lock;
struct list_head ref_list;
struct drm_open_hash ref_hash[TTM_REF_NUM];
struct kref refcount;
};
/**
* struct ttm_object_device
*
* @object_lock: lock that protects the object_hash hash table.
*
* @object_hash: hash table for fast lookup of object global names.
*
* @object_count: Per device object count.
*
* This is the per-device data structure needed for ttm object management.
*/
struct ttm_object_device {
spinlock_t object_lock;
struct drm_open_hash object_hash;
atomic_t object_count;
struct ttm_mem_global *mem_glob;
struct dma_buf_ops ops;
void (*dmabuf_release)(struct dma_buf *dma_buf);
size_t dma_buf_size;
};
/**
* struct ttm_ref_object
*
* @hash: Hash entry for the per-file object reference hash.
*
* @head: List entry for the per-file list of ref-objects.
*
* @kref: Ref count.
*
* @obj: Base object this ref object is referencing.
*
* @ref_type: Type of ref object.
*
* This is similar to an idr object, but it also has a hash table entry
* that allows lookup with a pointer to the referenced object as a key. In
* that way, one can easily detect whether a base object is referenced by
* a particular ttm_object_file. It also carries a ref count to avoid creating
* multiple ref objects if a ttm_object_file references the same base
* object more than once.
*/
struct ttm_ref_object {
struct rcu_head rcu_head;
struct drm_hash_item hash;
struct list_head head;
struct kref kref;
enum ttm_ref_type ref_type;
struct ttm_base_object *obj;
struct ttm_object_file *tfile;
};
static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);
static inline struct ttm_object_file *
ttm_object_file_ref(struct ttm_object_file *tfile)
{
kref_get(&tfile->refcount);
return tfile;
}
static void ttm_object_file_destroy(struct kref *kref)
{
struct ttm_object_file *tfile =
container_of(kref, struct ttm_object_file, refcount);
kfree(tfile);
}
static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
{
struct ttm_object_file *tfile = *p_tfile;
*p_tfile = NULL;
kref_put(&tfile->refcount, ttm_object_file_destroy);
}
int ttm_base_object_init(struct ttm_object_file *tfile,
struct ttm_base_object *base,
bool shareable,
enum ttm_object_type object_type,
void (*refcount_release) (struct ttm_base_object **),
void (*ref_obj_release) (struct ttm_base_object *,
enum ttm_ref_type ref_type))
{
struct ttm_object_device *tdev = tfile->tdev;
int ret;
base->shareable = shareable;
base->tfile = ttm_object_file_ref(tfile);
base->refcount_release = refcount_release;
base->ref_obj_release = ref_obj_release;
base->object_type = object_type;
kref_init(&base->refcount);
spin_lock(&tdev->object_lock);
ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
&base->hash,
(unsigned long)base, 31, 0, 0);
spin_unlock(&tdev->object_lock);
if (unlikely(ret != 0))
goto out_err0;
ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
if (unlikely(ret != 0))
goto out_err1;
ttm_base_object_unref(&base);
return 0;
out_err1:
spin_lock(&tdev->object_lock);
(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
spin_unlock(&tdev->object_lock);
out_err0:
return ret;
}
EXPORT_SYMBOL(ttm_base_object_init);
static void ttm_release_base(struct kref *kref)
{
struct ttm_base_object *base =
container_of(kref, struct ttm_base_object, refcount);
struct ttm_object_device *tdev = base->tfile->tdev;
spin_lock(&tdev->object_lock);
(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
spin_unlock(&tdev->object_lock);
/*
* Note: We don't use synchronize_rcu() here because it's far
* too slow. It's up to the user to free the object using
* call_rcu() or ttm_base_object_kfree().
*/
ttm_object_file_unref(&base->tfile);
if (base->refcount_release)
base->refcount_release(&base);
}
void ttm_base_object_unref(struct ttm_base_object **p_base)
{
struct ttm_base_object *base = *p_base;
*p_base = NULL;
kref_put(&base->refcount, ttm_release_base);
}
EXPORT_SYMBOL(ttm_base_object_unref);
struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
uint32_t key)
{
struct ttm_base_object *base = NULL;
struct drm_hash_item *hash;
struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
int ret;
rcu_read_lock();
ret = drm_ht_find_item_rcu(ht, key, &hash);
if (likely(ret == 0)) {
base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
if (!kref_get_unless_zero(&base->refcount))
base = NULL;
}
rcu_read_unlock();
return base;
}
EXPORT_SYMBOL(ttm_base_object_lookup);
struct ttm_base_object *
ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
{
struct ttm_base_object *base = NULL;
struct drm_hash_item *hash;
struct drm_open_hash *ht = &tdev->object_hash;
int ret;
rcu_read_lock();
ret = drm_ht_find_item_rcu(ht, key, &hash);
if (likely(ret == 0)) {
base = drm_hash_entry(hash, struct ttm_base_object, hash);
if (!kref_get_unless_zero(&base->refcount))
base = NULL;
}
rcu_read_unlock();
return base;
}
EXPORT_SYMBOL(ttm_base_object_lookup_for_ref);
int ttm_ref_object_add(struct ttm_object_file *tfile,
struct ttm_base_object *base,
enum ttm_ref_type ref_type, bool *existed)
{
struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
struct ttm_ref_object *ref;
struct drm_hash_item *hash;
struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
int ret = -EINVAL;
if (existed != NULL)
*existed = true;
while (ret == -EINVAL) {
rcu_read_lock();
ret = drm_ht_find_item_rcu(ht, base->hash.key, &hash);
if (ret == 0) {
ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
if (kref_get_unless_zero(&ref->kref)) {
rcu_read_unlock();
break;
}
}
rcu_read_unlock();
ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
false, false);
if (unlikely(ret != 0))
return ret;
ref = kmalloc(sizeof(*ref), GFP_KERNEL);
if (unlikely(ref == NULL)) {
ttm_mem_global_free(mem_glob, sizeof(*ref));
return -ENOMEM;
}
ref->hash.key = base->hash.key;
ref->obj = base;
ref->tfile = tfile;
ref->ref_type = ref_type;
kref_init(&ref->kref);
spin_lock(&tfile->lock);
ret = drm_ht_insert_item_rcu(ht, &ref->hash);
if (likely(ret == 0)) {
list_add_tail(&ref->head, &tfile->ref_list);
kref_get(&base->refcount);
spin_unlock(&tfile->lock);
if (existed != NULL)
*existed = false;
break;
}
spin_unlock(&tfile->lock);
BUG_ON(ret != -EINVAL);
ttm_mem_global_free(mem_glob, sizeof(*ref));
kfree(ref);
}
return ret;
}
EXPORT_SYMBOL(ttm_ref_object_add);
static void ttm_ref_object_release(struct kref *kref)
{
struct ttm_ref_object *ref =
container_of(kref, struct ttm_ref_object, kref);
struct ttm_base_object *base = ref->obj;
struct ttm_object_file *tfile = ref->tfile;
struct drm_open_hash *ht;
struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
ht = &tfile->ref_hash[ref->ref_type];
(void)drm_ht_remove_item_rcu(ht, &ref->hash);
list_del(&ref->head);
spin_unlock(&tfile->lock);
if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
base->ref_obj_release(base, ref->ref_type);
ttm_base_object_unref(&ref->obj);
ttm_mem_global_free(mem_glob, sizeof(*ref));
kfree_rcu(ref, rcu_head);
spin_lock(&tfile->lock);
}
int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
unsigned long key, enum ttm_ref_type ref_type)
{
struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
struct ttm_ref_object *ref;
struct drm_hash_item *hash;
int ret;
spin_lock(&tfile->lock);
ret = drm_ht_find_item(ht, key, &hash);
if (unlikely(ret != 0)) {
spin_unlock(&tfile->lock);
return -EINVAL;
}
ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
kref_put(&ref->kref, ttm_ref_object_release);
spin_unlock(&tfile->lock);
return 0;
}
EXPORT_SYMBOL(ttm_ref_object_base_unref);
void ttm_object_file_release(struct ttm_object_file **p_tfile)
{
struct ttm_ref_object *ref;
struct list_head *list;
unsigned int i;
struct ttm_object_file *tfile = *p_tfile;
*p_tfile = NULL;
spin_lock(&tfile->lock);
/*
* Since we release the lock within the loop, we have to
* restart it from the beginning each time.
*/
while (!list_empty(&tfile->ref_list)) {
list = tfile->ref_list.next;
ref = list_entry(list, struct ttm_ref_object, head);
ttm_ref_object_release(&ref->kref);
}
for (i = 0; i < TTM_REF_NUM; ++i)
drm_ht_remove(&tfile->ref_hash[i]);
spin_unlock(&tfile->lock);
ttm_object_file_unref(&tfile);
}
EXPORT_SYMBOL(ttm_object_file_release);
struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
unsigned int hash_order)
{
struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
unsigned int i;
unsigned int j = 0;
int ret;
if (unlikely(tfile == NULL))
return NULL;
spin_lock_init(&tfile->lock);
tfile->tdev = tdev;
kref_init(&tfile->refcount);
INIT_LIST_HEAD(&tfile->ref_list);
for (i = 0; i < TTM_REF_NUM; ++i) {
ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
if (ret) {
j = i;
goto out_err;
}
}
return tfile;
out_err:
for (i = 0; i < j; ++i)
drm_ht_remove(&tfile->ref_hash[i]);
kfree(tfile);
return NULL;
}
EXPORT_SYMBOL(ttm_object_file_init);
struct ttm_object_device *
ttm_object_device_init(struct ttm_mem_global *mem_glob,
unsigned int hash_order,
const struct dma_buf_ops *ops)
{
struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
int ret;
if (unlikely(tdev == NULL))
return NULL;
tdev->mem_glob = mem_glob;
spin_lock_init(&tdev->object_lock);
atomic_set(&tdev->object_count, 0);
ret = drm_ht_create(&tdev->object_hash, hash_order);
if (ret != 0)
goto out_no_object_hash;
tdev->ops = *ops;
tdev->dmabuf_release = tdev->ops.release;
tdev->ops.release = ttm_prime_dmabuf_release;
tdev->dma_buf_size = ttm_round_pot(sizeof(struct dma_buf)) +
ttm_round_pot(sizeof(struct file));
return tdev;
out_no_object_hash:
kfree(tdev);
return NULL;
}
EXPORT_SYMBOL(ttm_object_device_init);
void ttm_object_device_release(struct ttm_object_device **p_tdev)
{
struct ttm_object_device *tdev = *p_tdev;
*p_tdev = NULL;
spin_lock(&tdev->object_lock);
drm_ht_remove(&tdev->object_hash);
spin_unlock(&tdev->object_lock);
kfree(tdev);
}
EXPORT_SYMBOL(ttm_object_device_release);
/**
* get_dma_buf_unless_doomed - get a dma_buf reference if possible.
*
* @dma_buf: Non-refcounted pointer to a struct dma-buf.
*
* Obtain a file reference from a lookup structure that doesn't refcount
* the file, but synchronizes with its release method to make sure it has
* not been freed yet. See for example kref_get_unless_zero documentation.
* Returns true if refcounting succeeds, false otherwise.
*
* Nobody really wants this as a public API yet, so let it mature here
* for some time...
*/
static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
{
return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
}
/**
* ttm_prime_refcount_release - refcount release method for a prime object.
*
* @p_base: Pointer to ttm_base_object pointer.
*
* This is a wrapper that calls the refcount_release founction of the
* underlying object. At the same time it cleans up the prime object.
* This function is called when all references to the base object we
* derive from are gone.
*/
static void ttm_prime_refcount_release(struct ttm_base_object **p_base)
{
struct ttm_base_object *base = *p_base;
struct ttm_prime_object *prime;
*p_base = NULL;
prime = container_of(base, struct ttm_prime_object, base);
BUG_ON(prime->dma_buf != NULL);
mutex_destroy(&prime->mutex);
if (prime->refcount_release)
prime->refcount_release(&base);
}
/**
* ttm_prime_dmabuf_release - Release method for the dma-bufs we export
*
* @dma_buf:
*
* This function first calls the dma_buf release method the driver
* provides. Then it cleans up our dma_buf pointer used for lookup,
* and finally releases the reference the dma_buf has on our base
* object.
*/
static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf)
{
struct ttm_prime_object *prime =
(struct ttm_prime_object *) dma_buf->priv;
struct ttm_base_object *base = &prime->base;
struct ttm_object_device *tdev = base->tfile->tdev;
if (tdev->dmabuf_release)
tdev->dmabuf_release(dma_buf);
mutex_lock(&prime->mutex);
if (prime->dma_buf == dma_buf)
prime->dma_buf = NULL;
mutex_unlock(&prime->mutex);
ttm_mem_global_free(tdev->mem_glob, tdev->dma_buf_size);
ttm_base_object_unref(&base);
}
/**
* ttm_prime_fd_to_handle - Get a base object handle from a prime fd
*
* @tfile: A struct ttm_object_file identifying the caller.
* @fd: The prime / dmabuf fd.
* @handle: The returned handle.
*
* This function returns a handle to an object that previously exported
* a dma-buf. Note that we don't handle imports yet, because we simply
* have no consumers of that implementation.
*/
int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
int fd, u32 *handle)
{
struct ttm_object_device *tdev = tfile->tdev;
struct dma_buf *dma_buf;
struct ttm_prime_object *prime;
struct ttm_base_object *base;
int ret;
dma_buf = dma_buf_get(fd);
if (IS_ERR(dma_buf))
return PTR_ERR(dma_buf);
if (dma_buf->ops != &tdev->ops)
return -ENOSYS;
prime = (struct ttm_prime_object *) dma_buf->priv;
base = &prime->base;
*handle = base->hash.key;
ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
dma_buf_put(dma_buf);
return ret;
}
EXPORT_SYMBOL_GPL(ttm_prime_fd_to_handle);
/**
* ttm_prime_handle_to_fd - Return a dma_buf fd from a ttm prime object
*
* @tfile: Struct ttm_object_file identifying the caller.
* @handle: Handle to the object we're exporting from.
* @flags: flags for dma-buf creation. We just pass them on.
* @prime_fd: The returned file descriptor.
*
*/
int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
uint32_t handle, uint32_t flags,
int *prime_fd)
{
struct ttm_object_device *tdev = tfile->tdev;
struct ttm_base_object *base;
struct dma_buf *dma_buf;
struct ttm_prime_object *prime;
int ret;
base = ttm_base_object_lookup(tfile, handle);
if (unlikely(base == NULL ||
base->object_type != ttm_prime_type)) {
ret = -ENOENT;
goto out_unref;
}
prime = container_of(base, struct ttm_prime_object, base);
if (unlikely(!base->shareable)) {
ret = -EPERM;
goto out_unref;
}
ret = mutex_lock_interruptible(&prime->mutex);
if (unlikely(ret != 0)) {
ret = -ERESTARTSYS;
goto out_unref;
}
dma_buf = prime->dma_buf;
if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
exp_info.ops = &tdev->ops;
exp_info.size = prime->size;
exp_info.flags = flags;
exp_info.priv = prime;
/*
* Need to create a new dma_buf, with memory accounting.
*/
ret = ttm_mem_global_alloc(tdev->mem_glob, tdev->dma_buf_size,
false, true);
if (unlikely(ret != 0)) {
mutex_unlock(&prime->mutex);
goto out_unref;
}
dma_buf = dma_buf_export(&exp_info);
if (IS_ERR(dma_buf)) {
ret = PTR_ERR(dma_buf);
ttm_mem_global_free(tdev->mem_glob,
tdev->dma_buf_size);
mutex_unlock(&prime->mutex);
goto out_unref;
}
/*
* dma_buf has taken the base object reference
*/
base = NULL;
prime->dma_buf = dma_buf;
}
mutex_unlock(&prime->mutex);
ret = dma_buf_fd(dma_buf, flags);
if (ret >= 0) {
*prime_fd = ret;
ret = 0;
} else
dma_buf_put(dma_buf);
out_unref:
if (base)
ttm_base_object_unref(&base);
return ret;
}
EXPORT_SYMBOL_GPL(ttm_prime_handle_to_fd);
/**
* ttm_prime_object_init - Initialize a ttm_prime_object
*
* @tfile: struct ttm_object_file identifying the caller
* @size: The size of the dma_bufs we export.
* @prime: The object to be initialized.
* @shareable: See ttm_base_object_init
* @type: See ttm_base_object_init
* @refcount_release: See ttm_base_object_init
* @ref_obj_release: See ttm_base_object_init
*
* Initializes an object which is compatible with the drm_prime model
* for data sharing between processes and devices.
*/
int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
struct ttm_prime_object *prime, bool shareable,
enum ttm_object_type type,
void (*refcount_release) (struct ttm_base_object **),
void (*ref_obj_release) (struct ttm_base_object *,
enum ttm_ref_type ref_type))
{
mutex_init(&prime->mutex);
prime->size = PAGE_ALIGN(size);
prime->real_type = type;
prime->dma_buf = NULL;
prime->refcount_release = refcount_release;
return ttm_base_object_init(tfile, &prime->base, shareable,
ttm_prime_type,
ttm_prime_refcount_release,
ref_obj_release);
}
EXPORT_SYMBOL(ttm_prime_object_init);