/**
* batadv_dat_entry_hash_find - look for a given dat_entry in the local hash
* table
* @bat_priv: the bat priv with all the soft interface information
* @ip: search key
* @vid: VLAN identifier
*
* Return: the dat_entry if found, NULL otherwise.
*/
static struct batadv_dat_entry *
batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip,
unsigned short vid)
{
struct hlist_head *head;
struct batadv_dat_entry to_find, *dat_entry, *dat_entry_tmp = NULL;
struct batadv_hashtable *hash = bat_priv->dat.hash;
u32 index;
if (!hash)
return NULL;
to_find.ip = ip;
to_find.vid = vid;
index = batadv_hash_dat(&to_find, hash->size);
head = &hash->table[index];
rcu_read_lock();
hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
if (dat_entry->ip != ip)
continue;
if (!kref_get_unless_zero(&dat_entry->refcount))
continue;
dat_entry_tmp = dat_entry;
break;
}
rcu_read_unlock();
return dat_entry_tmp;
}
struct drm_mode_object *__drm_mode_object_find(struct drm_device *dev,
struct drm_file *file_priv,
uint32_t id, uint32_t type)
{
struct drm_mode_object *obj = NULL;
mutex_lock(&dev->mode_config.idr_mutex);
obj = idr_find(&dev->mode_config.crtc_idr, id);
if (obj && type != DRM_MODE_OBJECT_ANY && obj->type != type)
obj = NULL;
if (obj && obj->id != id)
obj = NULL;
if (obj && drm_mode_object_lease_required(obj->type) &&
!_drm_lease_held(file_priv, obj->id))
obj = NULL;
if (obj && obj->free_cb) {
if (!kref_get_unless_zero(&obj->refcount))
obj = NULL;
}
mutex_unlock(&dev->mode_config.idr_mutex);
return obj;
}
struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair)
{
RCU_LOCKDEP_WARN(!rcu_read_lock_bh_held(),
"Taking noise keypair reference without holding the RCU BH read lock");
if (unlikely(!keypair || !kref_get_unless_zero(&keypair->refcount)))
return NULL;
return keypair;
}
static int i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
struct mm_struct *mm,
unsigned long start,
unsigned long end,
bool blockable)
{
struct i915_mmu_notifier *mn =
container_of(_mn, struct i915_mmu_notifier, mn);
struct i915_mmu_object *mo;
struct interval_tree_node *it;
LIST_HEAD(cancelled);
if (RB_EMPTY_ROOT(&mn->objects.rb_root))
return 0;
/* interval ranges are inclusive, but invalidate range is exclusive */
end--;
spin_lock(&mn->lock);
it = interval_tree_iter_first(&mn->objects, start, end);
while (it) {
if (!blockable) {
spin_unlock(&mn->lock);
return -EAGAIN;
}
/* The mmu_object is released late when destroying the
* GEM object so it is entirely possible to gain a
* reference on an object in the process of being freed
* since our serialisation is via the spinlock and not
* the struct_mutex - and consequently use it after it
* is freed and then double free it. To prevent that
* use-after-free we only acquire a reference on the
* object if it is not in the process of being destroyed.
*/
mo = container_of(it, struct i915_mmu_object, it);
if (kref_get_unless_zero(&mo->obj->base.refcount))
queue_work(mn->wq, &mo->work);
list_add(&mo->link, &cancelled);
it = interval_tree_iter_next(it, start, end);
}
list_for_each_entry(mo, &cancelled, link)
del_object(mo);
spin_unlock(&mn->lock);
if (!list_empty(&cancelled))
flush_workqueue(mn->wq);
return 0;
}
static struct bus1_user *
bus1_user_get(struct bus1_domain_info *domain_info, kuid_t uid)
{
struct bus1_user *user;
rcu_read_lock();
user = idr_find(&domain_info->user_idr, __kuid_val(uid));
if (user && !kref_get_unless_zero(&user->ref))
/* the user is about to be destroyed, ignore it */
user = NULL;
rcu_read_unlock();
return user;
}
struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
uint32_t key)
{
struct ttm_object_device *tdev = tfile->tdev;
struct ttm_base_object *base;
struct drm_hash_item *hash;
int ret;
mtx_enter(&tdev->object_lock);
ret = drm_ht_find_item(&tdev->object_hash, key, &hash);
if (likely(ret == 0)) {
base = drm_hash_entry(hash, struct ttm_base_object, hash);
ret = kref_get_unless_zero(&base->refcount) ? 0 : -EINVAL;
}
struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
uint32_t key)
{
struct ttm_object_device *tdev = tfile->tdev;
struct ttm_base_object *uninitialized_var(base);
struct drm_hash_item *hash;
int ret;
rcu_read_lock();
ret = drm_ht_find_item_rcu(&tdev->object_hash, key, &hash);
if (likely(ret == 0)) {
base = drm_hash_entry(hash, struct ttm_base_object, hash);
ret = kref_get_unless_zero(&base->refcount) ? 0 : -EINVAL;
}
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;
}
/**
* drm_gem_mmap - memory map routine for GEM objects
* @filp: DRM file pointer
* @vma: VMA for the area to be mapped
*
* If a driver supports GEM object mapping, mmap calls on the DRM file
* descriptor will end up here.
*
* Look up the GEM object based on the offset passed in (vma->vm_pgoff will
* contain the fake offset we created when the GTT map ioctl was called on
* the object) and map it with a call to drm_gem_mmap_obj().
*
* If the caller is not granted access to the buffer object, the mmap will fail
* with EACCES. Please see the vma manager for more information.
*/
int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct drm_file *priv = filp->private_data;
struct drm_device *dev = priv->minor->dev;
struct drm_gem_object *obj = NULL;
struct drm_vma_offset_node *node;
int ret;
if (drm_device_is_unplugged(dev))
return -ENODEV;
drm_vma_offset_lock_lookup(dev->vma_offset_manager);
node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
vma->vm_pgoff,
vma_pages(vma));
if (likely(node)) {
obj = container_of(node, struct drm_gem_object, vma_node);
/*
* When the object is being freed, after it hits 0-refcnt it
* proceeds to tear down the object. In the process it will
* attempt to remove the VMA offset and so acquire this
* mgr->vm_lock. Therefore if we find an object with a 0-refcnt
* that matches our range, we know it is in the process of being
* destroyed and will be freed as soon as we release the lock -
* so we have to check for the 0-refcnted object and treat it as
* invalid.
*/
if (!kref_get_unless_zero(&obj->refcount))
obj = NULL;
}
drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
if (!obj)
return -EINVAL;
if (!drm_vma_node_is_allowed(node, filp)) {
drm_gem_object_unreference_unlocked(obj);
return -EACCES;
}
ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
vma);
drm_gem_object_unreference_unlocked(obj);
return ret;
}
/**
* batadv_choose_next_candidate - select the next DHT candidate
* @bat_priv: the bat priv with all the soft interface information
* @cands: candidates array
* @select: number of candidates already present in the array
* @ip_key: key to look up in the DHT
* @last_max: pointer where the address of the selected candidate will be saved
*/
static void batadv_choose_next_candidate(struct batadv_priv *bat_priv,
struct batadv_dat_candidate *cands,
int select, batadv_dat_addr_t ip_key,
batadv_dat_addr_t *last_max)
{
batadv_dat_addr_t max = 0;
batadv_dat_addr_t tmp_max = 0;
struct batadv_orig_node *orig_node, *max_orig_node = NULL;
struct batadv_hashtable *hash = bat_priv->orig_hash;
struct hlist_head *head;
int i;
/* if no node is eligible as candidate, leave the candidate type as
* NOT_FOUND
*/
cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND;
/* iterate over the originator list and find the node with the closest
* dat_address which has not been selected yet
*/
for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
rcu_read_lock();
hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
/* the dht space is a ring using unsigned addresses */
tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dat_addr +
ip_key;
if (!batadv_is_orig_node_eligible(cands, select,
tmp_max, max,
*last_max, orig_node,
max_orig_node))
continue;
if (!kref_get_unless_zero(&orig_node->refcount))
continue;
max = tmp_max;
if (max_orig_node)
batadv_orig_node_put(max_orig_node);
max_orig_node = orig_node;
}
rcu_read_unlock();
}
struct amdgpu_bo_list *
amdgpu_bo_list_get(struct amdgpu_fpriv *fpriv, int id)
{
struct amdgpu_bo_list *result;
rcu_read_lock();
result = idr_find(&fpriv->bo_list_handles, id);
if (result) {
if (kref_get_unless_zero(&result->refcount)) {
rcu_read_unlock();
mutex_lock(&result->lock);
} else {
rcu_read_unlock();
result = NULL;
}
} else {
rcu_read_unlock();
}
return result;
}
int bsg_job_get(struct bsg_job *job)
{
return kref_get_unless_zero(&job->kref);
}
void dummy(void)
{
if (!kref_get_unless_zero(NULL))
return;
}
/* Maps free channel with device */
int nvhost_channel_map(struct nvhost_device_data *pdata,
struct nvhost_channel **channel,
void *identifier)
{
struct nvhost_master *host = NULL;
struct nvhost_channel *ch = NULL;
int max_channels = 0;
int index = 0;
if (!pdata) {
pr_err("%s: NULL device data\n", __func__);
return -EINVAL;
}
host = nvhost_get_host(pdata->pdev);
mutex_lock(&host->chlist_mutex);
max_channels = nvhost_channel_nb_channels(host);
/* check if the channel is still in use */
for (index = 0; index < max_channels; index++) {
ch = host->chlist[index];
if (ch->identifier == identifier
&& kref_get_unless_zero(&ch->refcount)) {
/* yes, client can continue using it */
*channel = ch;
mutex_unlock(&host->chlist_mutex);
return 0;
}
}
do {
index = find_first_zero_bit(host->allocated_channels,
max_channels);
if (index >= max_channels) {
mutex_unlock(&host->chlist_mutex);
mdelay(1);
mutex_lock(&host->chlist_mutex);
}
} while (index >= max_channels);
/* Reserve the channel */
set_bit(index, host->allocated_channels);
ch = host->chlist[index];
/* Bind the reserved channel to the device */
ch->dev = pdata->pdev;
ch->identifier = identifier;
kref_init(&ch->refcount);
/* allocate vm */
ch->vm = nvhost_vm_allocate(pdata->pdev);
if (!ch->vm)
goto err_alloc_vm;
/* Handle logging */
trace_nvhost_channel_map(pdata->pdev->name, ch->chid,
pdata->num_mapped_chs);
dev_dbg(&ch->dev->dev, "channel %d mapped\n", ch->chid);
mutex_unlock(&host->chlist_mutex);
*channel = ch;
return 0;
err_alloc_vm:
clear_bit(index, host->allocated_channels);
ch->dev = NULL;
ch->identifier = NULL;
mutex_unlock(&host->chlist_mutex);
return -ENOMEM;
}
/**
* bus1_user_acquire_by_uid() - get a user object for a uid in the given domain
* @domain: domain of the user
* @uid: uid of the user
*
* Find and return the user object for the uid if it exists, otherwise create it
* first. The caller is responsible to release their reference (and all derived
* references) before the parent domain is deactivated!
*
* Return: A user object for the given uid, ERR_PTR on failure.
*/
struct bus1_user *
bus1_user_acquire_by_uid(struct bus1_domain *domain, kuid_t uid)
{
struct bus1_user *user, *old_user, *new_user;
int r = 0;
WARN_ON(!uid_valid(uid));
lockdep_assert_held(&domain->active);
/* try to get the user without taking a lock */
user = bus1_user_get(domain->info, uid);
if (user)
return user;
/* didn't exist, allocate a new one */
new_user = bus1_user_new(domain->info, uid);
if (IS_ERR(new_user))
return new_user;
/*
* Allocate the smallest possible internal id for this user; used in
* arrays for accounting user quota in receiver pools.
*/
r = ida_simple_get(&domain->info->user_ida, 0, 0, GFP_KERNEL);
if (r < 0)
goto exit;
new_user->id = r;
mutex_lock(&domain->info->lock);
/*
* Someone else might have raced us outside the lock, so check if the
* user still does not exist.
*/
old_user = idr_find(&domain->info->user_idr, __kuid_val(uid));
if (likely(!old_user)) {
/* user does not exist, link the newly created one */
r = idr_alloc(&domain->info->user_idr, new_user,
__kuid_val(uid), __kuid_val(uid) + 1, GFP_KERNEL);
if (r < 0)
goto exit;
} else {
/* another allocation raced us, try re-using that one */
if (likely(kref_get_unless_zero(&old_user->ref))) {
user = old_user;
goto exit;
} else {
/* the other one is getting destroyed, replace it */
idr_replace(&domain->info->user_idr, new_user,
__kuid_val(uid));
old_user->uid = INVALID_UID; /* mark old as removed */
}
}
user = new_user;
new_user = NULL;
exit:
mutex_unlock(&domain->info->lock);
bus1_user_release(new_user);
if (r < 0)
return ERR_PTR(r);
return user;
}
/**
* xprt_switch_get - Return a reference to a rpc_xprt_switch
* @xps: pointer to struct rpc_xprt_switch
*
* Returns a reference to xps unless the refcount is already zero.
*/
struct rpc_xprt_switch *xprt_switch_get(struct rpc_xprt_switch *xps)
{
if (xps != NULL && kref_get_unless_zero(&xps->xps_kref))
return xps;
return NULL;
}
static int
userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
const struct mmu_notifier_range *range)
{
struct i915_mmu_notifier *mn =
container_of(_mn, struct i915_mmu_notifier, mn);
struct interval_tree_node *it;
struct mutex *unlock = NULL;
unsigned long end;
int ret = 0;
if (RB_EMPTY_ROOT(&mn->objects.rb_root))
return 0;
/* interval ranges are inclusive, but invalidate range is exclusive */
end = range->end - 1;
spin_lock(&mn->lock);
it = interval_tree_iter_first(&mn->objects, range->start, end);
while (it) {
struct drm_i915_gem_object *obj;
if (!mmu_notifier_range_blockable(range)) {
ret = -EAGAIN;
break;
}
/*
* The mmu_object is released late when destroying the
* GEM object so it is entirely possible to gain a
* reference on an object in the process of being freed
* since our serialisation is via the spinlock and not
* the struct_mutex - and consequently use it after it
* is freed and then double free it. To prevent that
* use-after-free we only acquire a reference on the
* object if it is not in the process of being destroyed.
*/
obj = container_of(it, struct i915_mmu_object, it)->obj;
if (!kref_get_unless_zero(&obj->base.refcount)) {
it = interval_tree_iter_next(it, range->start, end);
continue;
}
spin_unlock(&mn->lock);
if (!unlock) {
unlock = &mn->mm->i915->drm.struct_mutex;
switch (mutex_trylock_recursive(unlock)) {
default:
case MUTEX_TRYLOCK_FAILED:
if (mutex_lock_killable_nested(unlock, I915_MM_SHRINKER)) {
i915_gem_object_put(obj);
return -EINTR;
}
/* fall through */
case MUTEX_TRYLOCK_SUCCESS:
break;
case MUTEX_TRYLOCK_RECURSIVE:
unlock = ERR_PTR(-EEXIST);
break;
}
}
ret = i915_gem_object_unbind(obj);
if (ret == 0)
ret = __i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
i915_gem_object_put(obj);
if (ret)
goto unlock;
spin_lock(&mn->lock);
/*
* As we do not (yet) protect the mmu from concurrent insertion
* over this range, there is no guarantee that this search will
* terminate given a pathologic workload.
*/
it = interval_tree_iter_first(&mn->objects, range->start, end);
}
spin_unlock(&mn->lock);
unlock:
if (!IS_ERR_OR_NULL(unlock))
mutex_unlock(unlock);
return ret;
}
