[PATCH 1/3] [RFC]drm: add syncobj timeline support v4

Christian König christian.koenig at amd.com
Wed Sep 12 07:22:10 UTC 2018


Ping? Have you seen my comments here?

Looks like you haven't addressed any of them in your last mail.

Christian.

Am 06.09.2018 um 09:25 schrieb Christian König:
> Am 06.09.2018 um 08:25 schrieb Chunming Zhou:
>> VK_KHR_timeline_semaphore:
>> This extension introduces a new type of semaphore that has an integer 
>> payload
>> identifying a point in a timeline. Such timeline semaphores support the
>
> Drop the term semaphore here, better use syncobj.
>
>> following operations:
>>     * CPU query - A host operation that allows querying the payload 
>> of the
>>       timeline semaphore.
>>     * CPU wait - A host operation that allows a blocking wait for a
>>       timeline semaphore to reach a specified value.
>>     * Device wait - A device operation that allows waiting for a
>>       timeline semaphore to reach a specified value.
>>     * Device signal - A device operation that allows advancing the
>>       timeline semaphore to a specified value.
>>
>> Since it's a timeline, that means the front time point(PT) always is 
>> signaled before the late PT.
>> a. signal PT design:
>> Signal PT fence N depends on PT[N-1] fence and signal opertion fence, 
>> when PT[N] fence is signaled,
>> the timeline will increase to value of PT[N].
>> b. wait PT design:
>> Wait PT fence is signaled by reaching timeline point value, when 
>> timeline is increasing, will compare
>> wait PTs value with new timeline value, if PT value is lower than 
>> timeline value, then wait PT will be
>> signaled, otherwise keep in list. semaphore wait operation can wait 
>> on any point of timeline,
>> so need a RB tree to order them. And wait PT could ahead of signal 
>> PT, we need a sumission fence to
>> perform that.
>>
>> v2:
>> 1. remove unused DRM_SYNCOBJ_CREATE_TYPE_NORMAL. (Christian)
>> 2. move unexposed denitions to .c file. (Daniel Vetter)
>> 3. split up the change to drm_syncobj_find_fence() in a separate 
>> patch. (Christian)
>> 4. split up the change to drm_syncobj_replace_fence() in a separate 
>> patch.
>> 5. drop the submission_fence implementation and instead use 
>> wait_event() for that. (Christian)
>> 6. WARN_ON(point != 0) for NORMAL type syncobj case. (Daniel Vetter)
>>
>> v3:
>> 1. replace normal syncobj with timeline implemenation. (Vetter and 
>> Christian)
>>      a. normal syncobj signal op will create a signal PT to tail of 
>> signal pt list.
>>      b. normal syncobj wait op will create a wait pt with last signal 
>> point, and this wait PT is only signaled by related signal point PT.
>> 2. many bug fix and clean up
>> 3. stub fence moving is moved to other patch.
>>
>> v4:
>> 1. fix RB tree loop with while(node=rb_first(...)). (Christian)
>> 2. fix syncobj lifecycle. (Christian)
>> 3. only enable_signaling when there is wait_pt. (Christian)
>>
>> Tested by ./deqp-vk -n dEQP-VK*semaphore* for normal syncobj
>>
>> Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
>> Cc: Christian Konig <christian.koenig at amd.com>
>> Cc: Dave Airlie <airlied at redhat.com>
>> Cc: Daniel Rakos <Daniel.Rakos at amd.com>
>> Cc: Daniel Vetter <daniel at ffwll.ch>
>> ---
>>   drivers/gpu/drm/drm_syncobj.c              | 516 +++++++++++++++++----
>>   drivers/gpu/drm/i915/i915_gem_execbuffer.c |   4 +-
>>   include/drm/drm_syncobj.h                  |  78 ++--
>>   include/uapi/drm/drm.h                     |   1 +
>>   4 files changed, 448 insertions(+), 151 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_syncobj.c 
>> b/drivers/gpu/drm/drm_syncobj.c
>> index e9ce623d049e..94b31de23858 100644
>> --- a/drivers/gpu/drm/drm_syncobj.c
>> +++ b/drivers/gpu/drm/drm_syncobj.c
>> @@ -56,6 +56,9 @@
>>   #include "drm_internal.h"
>>   #include <drm/drm_syncobj.h>
>>   +/* merge normal syncobj to timeline syncobj, the point interval is 
>> 1 */
>> +#define DRM_SYNCOBJ_NORMAL_POINT 1
>> +
>>   struct drm_syncobj_stub_fence {
>>       struct dma_fence base;
>>       spinlock_t lock;
>> @@ -82,6 +85,18 @@ static const struct dma_fence_ops 
>> drm_syncobj_stub_fence_ops = {
>>       .release = drm_syncobj_stub_fence_release,
>>   };
>>   +struct drm_syncobj_signal_pt {
>> +    struct dma_fence_array *base;
>> +    u64    value;
>> +    struct list_head list;
>> +};
>> +struct drm_syncobj_wait_pt {
>> +    struct drm_syncobj_stub_fence base;
>> +    struct dma_fence *signal_pt_fence;
>> +    struct dma_fence_cb wait_cb;
>> +    struct rb_node   node;
>> +    u64    value;
>> +};
>>     /**
>>    * drm_syncobj_find - lookup and reference a sync object.
>> @@ -109,61 +124,238 @@ struct drm_syncobj *drm_syncobj_find(struct 
>> drm_file *file_private,
>>   }
>>   EXPORT_SYMBOL(drm_syncobj_find);
>>   -static void drm_syncobj_add_callback_locked(struct drm_syncobj 
>> *syncobj,
>> -                        struct drm_syncobj_cb *cb,
>> -                        drm_syncobj_func_t func)
>> +static void drm_syncobj_timeline_init(struct drm_syncobj *syncobj,
>> +                      struct drm_syncobj_timeline *syncobj_timeline)
>
> Since we merged timeline and singleton syncobj you can drop the extra 
> _timeline_ part in the function name I think.
>
>>   {
>> -    cb->func = func;
>> -    list_add_tail(&cb->node, &syncobj->cb_list);
>> +    spin_lock(&syncobj->lock);
>> +    syncobj_timeline->timeline_context = dma_fence_context_alloc(1);
>> +    syncobj_timeline->timeline = 0;
>> +    syncobj_timeline->signal_point = 0;
>> +    init_waitqueue_head(&syncobj_timeline->wq);
>> +
>> +    syncobj_timeline->wait_pt_tree = RB_ROOT;
>> +    INIT_LIST_HEAD(&syncobj_timeline->signal_pt_list);
>> +    spin_unlock(&syncobj->lock);
>>   }
>>   -static int drm_syncobj_fence_get_or_add_callback(struct 
>> drm_syncobj *syncobj,
>> -                         struct dma_fence **fence,
>> -                         struct drm_syncobj_cb *cb,
>> -                         drm_syncobj_func_t func)
>> +static void drm_syncobj_timeline_fini(struct drm_syncobj *syncobj,
>> +                      struct drm_syncobj_timeline *syncobj_timeline)
>>   {
>> -    int ret;
>> -
>> -    *fence = drm_syncobj_fence_get(syncobj);
>> -    if (*fence)
>> -        return 1;
>> +    struct rb_node *node = NULL;
>> +    struct drm_syncobj_wait_pt *wait_pt = NULL;
>> +    struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
>>         spin_lock(&syncobj->lock);
>> -    /* We've already tried once to get a fence and failed.  Now that we
>> -     * have the lock, try one more time just to be sure we don't add a
>> -     * callback when a fence has already been set.
>> -     */
>> -    if (syncobj->fence) {
>> -        *fence = 
>> dma_fence_get(rcu_dereference_protected(syncobj->fence,
>> - lockdep_is_held(&syncobj->lock)));
>> -        ret = 1;
>> -    } else {
>> -        *fence = NULL;
>> -        drm_syncobj_add_callback_locked(syncobj, cb, func);
>> -        ret = 0;
>> +    if (!RB_EMPTY_ROOT(&syncobj_timeline->wait_pt_tree))
>> +        DRM_ERROR("There still are advanced wait_pts! pls check!");
>> +    while ((node = rb_first(&syncobj_timeline->wait_pt_tree))) {
>> +        wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
>> +        rb_erase(&wait_pt->node,
>> +             &syncobj_timeline->wait_pt_tree);
>> +        RB_CLEAR_NODE(&wait_pt->node);
>> +        if (!wait_pt->signal_pt_fence) {
>> +            /* if wait_pt still is advanced, fake signal it.
>> +             * generally shouldn't happens */
>> +            dma_fence_set_error(&wait_pt->base.base, -ENOENT);
>> +            dma_fence_signal(&wait_pt->base.base);
>> +        }
>> +        /* kfree(wait_pt) is excuted by fence put */
>> +        dma_fence_put(&wait_pt->base.base);
>> +    }
>> +    list_for_each_entry_safe(signal_pt, tmp,
>> +                 &syncobj_timeline->signal_pt_list, list) {
>> +        list_del(&signal_pt->list);
>> +        dma_fence_put(&signal_pt->base->base);
>> +        kfree(signal_pt);
>>       }
>>       spin_unlock(&syncobj->lock);
>> +}
>>   -    return ret;
>> +static void wait_pt_func(struct dma_fence *fence, struct 
>> dma_fence_cb *cb)
>> +{
>> +    struct drm_syncobj_wait_pt *wait_pt =
>> +        container_of(cb, struct drm_syncobj_wait_pt, wait_cb);
>> +
>> +    dma_fence_signal(&wait_pt->base.base);
>> +    dma_fence_put(wait_pt->signal_pt_fence);
>> +    wait_pt->signal_pt_fence = NULL;
>> +    dma_fence_put(&wait_pt->base.base);
>> +}
>> +
>> +static void drm_syncobj_find_signal_pt_for_wait_pt(struct 
>> drm_syncobj *syncobj,
>> +                           struct drm_syncobj_wait_pt *wait_pt)
>> +{
>
> That whole approach still looks horrible complicated to me.
>
> Especially the separation of signal and wait pt is completely 
> unnecessary as far as I can see.
>
> When a wait pt is requested we just need to search for the signal 
> point which it will trigger.
>
> Regards,
> Christian.
>
>> +    struct drm_syncobj_timeline *timeline = &syncobj->syncobj_timeline;
>> +    struct drm_syncobj_signal_pt *signal_pt;
>> +    int ret;
>> +
>> +    if (wait_pt->signal_pt_fence) {
>> +        return;
>> +    } else if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) &&
>> +           (wait_pt->value <= timeline->timeline)) {
>> +        dma_fence_signal(&wait_pt->base.base);
>> +        rb_erase(&wait_pt->node,
>> +             &timeline->wait_pt_tree);
>> +        RB_CLEAR_NODE(&wait_pt->node);
>> +        dma_fence_put(&wait_pt->base.base);
>> +        return;
>> +    }
>> +
>> +    list_for_each_entry(signal_pt, &timeline->signal_pt_list, list) {
>> +        if (wait_pt->value < signal_pt->value)
>> +            continue;
>> +        if ((syncobj->type == DRM_SYNCOBJ_TYPE_NORMAL) &&
>> +            (wait_pt->value != signal_pt->value))
>> +            continue;
>> +        wait_pt->signal_pt_fence = 
>> dma_fence_get(&signal_pt->base->base);
>> +        ret = dma_fence_add_callback(wait_pt->signal_pt_fence,
>> +                         &wait_pt->wait_cb,
>> +                         wait_pt_func);
>> +        if (ret == -ENOENT) {
>> +            dma_fence_signal(&wait_pt->base.base);
>> +            dma_fence_put(wait_pt->signal_pt_fence);
>> +            wait_pt->signal_pt_fence = NULL;
>> +            rb_erase(&wait_pt->node,
>> +                 &timeline->wait_pt_tree);
>> +            RB_CLEAR_NODE(&wait_pt->node);
>> +            dma_fence_put(&wait_pt->base.base);
>> +        } else if (ret < 0) {
>> +            dma_fence_put(wait_pt->signal_pt_fence);
>> +            DRM_ERROR("add callback error!");
>> +        } else {
>> +            /* after adding callback, remove from rb tree */
>> +            rb_erase(&wait_pt->node,
>> +                 &timeline->wait_pt_tree);
>> +            RB_CLEAR_NODE(&wait_pt->node);
>> +        }
>> +        return;
>> +    }
>> +    /* signaled pt was released */
>> +    if (!wait_pt->signal_pt_fence && (wait_pt->value <=
>> +                      timeline->signal_point)) {
>> +        dma_fence_signal(&wait_pt->base.base);
>> +        rb_erase(&wait_pt->node,
>> +             &timeline->wait_pt_tree);
>> +        RB_CLEAR_NODE(&wait_pt->node);
>> +        dma_fence_put(&wait_pt->base.base);
>> +    }
>>   }
>>   -void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
>> -                  struct drm_syncobj_cb *cb,
>> -                  drm_syncobj_func_t func)
>> +static int drm_syncobj_timeline_create_signal_pt(struct drm_syncobj 
>> *syncobj,
>> +                         struct dma_fence *fence,
>> +                         u64 point)
>>   {
>> +    struct drm_syncobj_signal_pt *signal_pt =
>> +        kzalloc(sizeof(struct drm_syncobj_signal_pt), GFP_KERNEL);
>> +    struct drm_syncobj_signal_pt *tail_pt;
>> +    struct dma_fence **fences;
>> +    struct rb_node *node;
>> +    struct drm_syncobj_wait_pt *tail_wait_pt = NULL;
>> +    int num_fences = 0;
>> +    int ret = 0, i;
>> +
>> +    if (!signal_pt)
>> +        return -ENOMEM;
>> +    if (syncobj->syncobj_timeline.signal_point >= point) {
>> +        DRM_WARN("A later signal is ready!");
>> +        goto out;
>> +    }
>> +    if (!fence)
>> +        goto out;
>> +
>> +    fences = kmalloc_array(sizeof(void *), 2, GFP_KERNEL);
>> +    if (!fences)
>> +        goto out;
>> +    fences[num_fences++] = dma_fence_get(fence);
>> +    /* timeline syncobj must take this dependency */
>> +    if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
>> +        spin_lock(&syncobj->lock);
>> +        if (!list_empty(&syncobj->syncobj_timeline.signal_pt_list)) {
>> +            tail_pt = 
>> list_last_entry(&syncobj->syncobj_timeline.signal_pt_list,
>> +                          struct drm_syncobj_signal_pt, list);
>> +            fences[num_fences++] = dma_fence_get(&tail_pt->base->base);
>> +        }
>> +        spin_unlock(&syncobj->lock);
>> +    }
>> +    signal_pt->base = dma_fence_array_create(num_fences, fences,
>> + syncobj->syncobj_timeline.timeline_context,
>> +                         point, false);
>> +    if (!signal_pt->base)
>> +        goto fail;
>> +
>> +    signal_pt->value = point;
>>       spin_lock(&syncobj->lock);
>> -    drm_syncobj_add_callback_locked(syncobj, cb, func);
>> +    syncobj->syncobj_timeline.signal_point = point;
>> +    INIT_LIST_HEAD(&signal_pt->list);
>> +    list_add_tail(&signal_pt->list, 
>> &syncobj->syncobj_timeline.signal_pt_list);
>> +
>> +    /* check if there is advanced wait */
>> +    node = rb_last(&syncobj->syncobj_timeline.wait_pt_tree);
>> +    if (node)
>> +        tail_wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, 
>> node);
>> +    if (tail_wait_pt && !tail_wait_pt->signal_pt_fence) {
>> +        for (node = rb_first(&syncobj->syncobj_timeline.wait_pt_tree);
>> +             node != NULL; node = rb_next(node)) {
>> +            struct drm_syncobj_wait_pt *wait_pt =
>> +                rb_entry(node, struct drm_syncobj_wait_pt,
>> +                     node);
>> +
>> +            drm_syncobj_find_signal_pt_for_wait_pt(syncobj,
>> +                                   wait_pt);
>> +        }
>> +    }
>> +
>>       spin_unlock(&syncobj->lock);
>> +    wake_up_all(&syncobj->syncobj_timeline.wq);
>> +
>> +    return 0;
>> +fail:
>> +    for (i = 0; i < num_fences; i++)
>> +        dma_fence_put(fences[i]);
>> +    kfree(fences);
>> +out:
>> +    kfree(signal_pt);
>> +    return ret;
>>   }
>>   -void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
>> -                 struct drm_syncobj_cb *cb)
>> +static void drm_syncobj_timeline_garbage_collection(struct 
>> drm_syncobj *syncobj)
>>   {
>> +    struct drm_syncobj_timeline *timeline = &syncobj->syncobj_timeline;
>> +    struct rb_node *node;
>> +    struct drm_syncobj_wait_pt *wait_pt;
>> +    struct drm_syncobj_signal_pt *signal_pt, *tmp;
>> +
>>       spin_lock(&syncobj->lock);
>> -    list_del_init(&cb->node);
>> +    node = rb_first(&timeline->wait_pt_tree);
>> +    while (node) {
>> +        wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
>> +        if (!dma_fence_is_signaled(&wait_pt->base.base)) {
>> +            node = rb_next(node);
>> +            continue;
>> +        }
>> +        rb_erase(&wait_pt->node,
>> +             &timeline->wait_pt_tree);
>> +        RB_CLEAR_NODE(&wait_pt->node);
>> +        /* kfree(wait_pt) is excuted by fence put */
>> +        dma_fence_put(&wait_pt->base.base);
>> +        node = rb_first(&timeline->wait_pt_tree);
>> +    }
>> +    list_for_each_entry_safe(signal_pt, tmp,
>> +                 &timeline->signal_pt_list, list) {
>> +        if (dma_fence_is_signaled(&signal_pt->base->base)) {
>> +            timeline->timeline = signal_pt->value;
>> +            list_del(&signal_pt->list);
>> +            dma_fence_put(&signal_pt->base->base);
>> +            kfree(signal_pt);
>> +        } else {
>> +            /*signal_pt is in order in list, from small to big, so
>> +             * the later must not be signal either */
>> +            break;
>> +        }
>> +    }
>> +
>>       spin_unlock(&syncobj->lock);
>>   }
>> -
>>   /**
>>    * drm_syncobj_replace_fence - replace fence in a sync object.
>>    * @syncobj: Sync object to replace fence in
>> @@ -176,28 +368,29 @@ void drm_syncobj_replace_fence(struct 
>> drm_syncobj *syncobj,
>>                      u64 point,
>>                      struct dma_fence *fence)
>>   {
>> -    struct dma_fence *old_fence;
>> -    struct drm_syncobj_cb *cur, *tmp;
>> -
>> -    if (fence)
>> -        dma_fence_get(fence);
>> -
>> -    spin_lock(&syncobj->lock);
>> -
>> -    old_fence = rcu_dereference_protected(syncobj->fence,
>> - lockdep_is_held(&syncobj->lock));
>> -    rcu_assign_pointer(syncobj->fence, fence);
>> -
>> -    if (fence != old_fence) {
>> -        list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) {
>> -            list_del_init(&cur->node);
>> -            cur->func(syncobj, cur);
>> +    drm_syncobj_timeline_garbage_collection(syncobj);
>> +    if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
>> +        if (fence)
>> +            drm_syncobj_timeline_create_signal_pt(syncobj, fence,
>> +                                  point);
>> +        return;
>> +    } else if (syncobj->type == DRM_SYNCOBJ_TYPE_NORMAL) {
>> +        u64 pt_value;
>> +
>> +        if (!fence) {
>> +            drm_syncobj_timeline_fini(syncobj,
>> +                          &syncobj->syncobj_timeline);
>> +            drm_syncobj_timeline_init(syncobj,
>> +                          &syncobj->syncobj_timeline);
>> +            return;
>>           }
>> +        pt_value = syncobj->syncobj_timeline.signal_point +
>> +            DRM_SYNCOBJ_NORMAL_POINT;
>> +        drm_syncobj_timeline_create_signal_pt(syncobj, fence, 
>> pt_value);
>> +        return;
>> +    } else {
>> +        DRM_ERROR("the syncobj type isn't support\n");
>>       }
>> -
>> -    spin_unlock(&syncobj->lock);
>> -
>> -    dma_fence_put(old_fence);
>>   }
>>   EXPORT_SYMBOL(drm_syncobj_replace_fence);
>>   @@ -220,6 +413,120 @@ static int 
>> drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
>>       return 0;
>>   }
>>   +static struct drm_syncobj_wait_pt *
>> +drm_syncobj_timeline_lookup_wait_pt_fence(struct drm_syncobj *syncobj,
>> +                      u64 point,
>> +                      struct dma_fence **fence)
>> +{
>> +    struct rb_node *node = 
>> syncobj->syncobj_timeline.wait_pt_tree.rb_node;
>> +    struct drm_syncobj_wait_pt *wait_pt = NULL;
>> +
>> +    spin_lock(&syncobj->lock);
>> +    while(node) {
>> +        int result;
>> +
>> +        wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
>> +        result = point - wait_pt->value;
>> +        if (result < 0) {
>> +            node = node->rb_left;
>> +        } else if (result > 0) {
>> +            node = node->rb_right;
>> +        } else {
>> +            if (fence)
>> +                *fence = dma_fence_get(&wait_pt->base.base);
>> +            break;
>> +        }
>> +    }
>> +    spin_unlock(&syncobj->lock);
>> +
>> +    return wait_pt;
>> +}
>> +
>> +static struct drm_syncobj_wait_pt *
>> +drm_syncobj_timeline_create_wait_pt_and_return_fence(struct 
>> drm_syncobj *syncobj,
>> +                             u64 point,
>> +                             struct dma_fence **fence)
>> +{
>> +    struct drm_syncobj_wait_pt *wait_pt = kzalloc(sizeof(*wait_pt),
>> +                              GFP_KERNEL);
>> +    struct drm_syncobj_stub_fence *base;
>> +    struct rb_node **new = 
>> &(syncobj->syncobj_timeline.wait_pt_tree.rb_node), *parent = NULL;
>> +
>> +    if (!wait_pt)
>> +        return NULL;
>> +    base = &wait_pt->base;
>> +    spin_lock_init(&base->lock);
>> +    dma_fence_init(&base->base,
>> +               &drm_syncobj_stub_fence_ops,
>> +               &base->lock,
>> +               syncobj->syncobj_timeline.timeline_context, point);
>> +    wait_pt->value = point;
>> +    wait_pt->signal_pt_fence = NULL;
>> +
>> +    /* wait pt must be in an order, so that we can easily lookup and 
>> signal
>> +     * it */
>> +    spin_lock(&syncobj->lock);
>> +    while(*new) {
>> +        struct drm_syncobj_wait_pt *this =
>> +            rb_entry(*new, struct drm_syncobj_wait_pt, node);
>> +        int result = wait_pt->value - this->value;
>> +
>> +        parent = *new;
>> +        if (result < 0)
>> +            new = &((*new)->rb_left);
>> +        else if (result > 0)
>> +            new = &((*new)->rb_right);
>> +        else
>> +            goto exist;
>> +    }
>> +    if (fence)
>> +        *fence = dma_fence_get(&wait_pt->base.base);
>> +    rb_link_node(&wait_pt->node, parent, new);
>> +    rb_insert_color(&wait_pt->node, 
>> &syncobj->syncobj_timeline.wait_pt_tree);
>> +    spin_unlock(&syncobj->lock);
>> +    return wait_pt;
>> +exist:
>> +    spin_unlock(&syncobj->lock);
>> +    dma_fence_put(&wait_pt->base.base);
>> +    wait_pt = drm_syncobj_timeline_lookup_wait_pt_fence(syncobj, point,
>> +                                fence);
>> +    return wait_pt;
>> +}
>> +
>> +static struct dma_fence *
>> +drm_syncobj_timeline_point_get(struct drm_syncobj *syncobj, u64 
>> point, u64 flags)
>> +{
>> +    struct drm_syncobj_wait_pt *wait_pt;
>> +    struct dma_fence *fence = NULL;
>> +
>> +    /* check if the wait pt exists */
>> +    wait_pt = drm_syncobj_timeline_lookup_wait_pt_fence(syncobj, point,
>> +                                &fence);
>> +    if (!fence) {
>> +        /* This is a new wait pt, so create it */
>> +        wait_pt = 
>> drm_syncobj_timeline_create_wait_pt_and_return_fence(syncobj, point,
>> +                                  &fence);
>> +        if (!fence)
>> +            return NULL;
>> +    }
>> +    if (wait_pt) {
>> +        int ret = 0;
>> +
>> +        if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
>> +            ret = 
>> wait_event_interruptible_timeout(syncobj->syncobj_timeline.wq,
>> +                                   wait_pt->value <= 
>> syncobj->syncobj_timeline.signal_point,
>> +                                   msecs_to_jiffies(10000)); /* wait 
>> 10s */
>> +            if (ret <= 0)
>> +                return NULL;
>> +        }
>> +        spin_lock(&syncobj->lock);
>> +        drm_syncobj_find_signal_pt_for_wait_pt(syncobj, wait_pt);
>> +        spin_unlock(&syncobj->lock);
>> +        return fence;
>> +    }
>> +    return NULL;
>> +}
>> +
>>   /**
>>    * drm_syncobj_find_fence - lookup and reference the fence in a 
>> sync object
>>    * @file_private: drm file private pointer
>> @@ -234,20 +541,46 @@ static int 
>> drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
>>    * contains a reference to the fence, which must be released by 
>> calling
>>    * dma_fence_put().
>>    */
>> -int drm_syncobj_find_fence(struct drm_file *file_private,
>> -               u32 handle, u64 point,
>> -               struct dma_fence **fence)
>> +int drm_syncobj_search_fence(struct drm_syncobj *syncobj, u64 point,
>> +                 u64 flags, struct dma_fence **fence)
>>   {
>> -    struct drm_syncobj *syncobj = drm_syncobj_find(file_private, 
>> handle);
>>       int ret = 0;
>>         if (!syncobj)
>>           return -ENOENT;
>>   -    *fence = drm_syncobj_fence_get(syncobj);
>> +    drm_syncobj_timeline_garbage_collection(syncobj);
>> +    if (syncobj->type == DRM_SYNCOBJ_TYPE_NORMAL) {
>> +        /*NORMAL syncobj always wait on last pt */
>> +        u64 tail_pt_value = syncobj->syncobj_timeline.signal_point;
>> +
>> +        if (tail_pt_value == 0)
>> +            tail_pt_value += DRM_SYNCOBJ_NORMAL_POINT;
>> +        /* NORMAL syncobj doesn't care point value */
>> +        WARN_ON(point != 0);
>> +        *fence = drm_syncobj_timeline_point_get(syncobj, tail_pt_value,
>> +                            flags);
>> +    } else if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
>> +        *fence = drm_syncobj_timeline_point_get(syncobj, point,
>> +                            flags);
>> +    } else {
>> +        DRM_ERROR("Don't support this type syncobj\n");
>> +        *fence = NULL;
>> +    }
>>       if (!*fence) {
>>           ret = -EINVAL;
>>       }
>> +    return ret;
>> +}
>> +EXPORT_SYMBOL(drm_syncobj_search_fence);
>> +int drm_syncobj_find_fence(struct drm_file *file_private,
>> +               u32 handle, u64 point,
>> +               struct dma_fence **fence) {
>> +    struct drm_syncobj *syncobj = drm_syncobj_find(file_private, 
>> handle);
>> +
>> +    int ret = drm_syncobj_search_fence(syncobj, point,
>> +                    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT,
>> +                    fence);
>>       drm_syncobj_put(syncobj);
>>       return ret;
>>   }
>> @@ -264,7 +597,7 @@ void drm_syncobj_free(struct kref *kref)
>>       struct drm_syncobj *syncobj = container_of(kref,
>>                              struct drm_syncobj,
>>                              refcount);
>> -    drm_syncobj_replace_fence(syncobj, 0, NULL);
>> +    drm_syncobj_timeline_fini(syncobj, &syncobj->syncobj_timeline);
>>       kfree(syncobj);
>>   }
>>   EXPORT_SYMBOL(drm_syncobj_free);
>> @@ -292,8 +625,12 @@ int drm_syncobj_create(struct drm_syncobj 
>> **out_syncobj, uint32_t flags,
>>           return -ENOMEM;
>>         kref_init(&syncobj->refcount);
>> -    INIT_LIST_HEAD(&syncobj->cb_list);
>>       spin_lock_init(&syncobj->lock);
>> +    if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE)
>> +        syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE;
>> +    else
>> +        syncobj->type = DRM_SYNCOBJ_TYPE_NORMAL;
>> +    drm_syncobj_timeline_init(syncobj, &syncobj->syncobj_timeline);
>>         if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
>>           ret = drm_syncobj_assign_null_handle(syncobj);
>> @@ -651,7 +988,6 @@ struct syncobj_wait_entry {
>>       struct task_struct *task;
>>       struct dma_fence *fence;
>>       struct dma_fence_cb fence_cb;
>> -    struct drm_syncobj_cb syncobj_cb;
>>   };
>>     static void syncobj_wait_fence_func(struct dma_fence *fence,
>> @@ -663,18 +999,6 @@ static void syncobj_wait_fence_func(struct 
>> dma_fence *fence,
>>       wake_up_process(wait->task);
>>   }
>>   -static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj,
>> -                      struct drm_syncobj_cb *cb)
>> -{
>> -    struct syncobj_wait_entry *wait =
>> -        container_of(cb, struct syncobj_wait_entry, syncobj_cb);
>> -
>> -    /* This happens inside the syncobj lock */
>> -    wait->fence = 
>> dma_fence_get(rcu_dereference_protected(syncobj->fence,
>> - lockdep_is_held(&syncobj->lock)));
>> -    wake_up_process(wait->task);
>> -}
>> -
>>   static signed long drm_syncobj_array_wait_timeout(struct 
>> drm_syncobj **syncobjs,
>>                             uint32_t count,
>>                             uint32_t flags,
>> @@ -698,14 +1022,11 @@ static signed long 
>> drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
>>       signaled_count = 0;
>>       for (i = 0; i < count; ++i) {
>>           entries[i].task = current;
>> -        entries[i].fence = drm_syncobj_fence_get(syncobjs[i]);
>> +        ret = drm_syncobj_search_fence(syncobjs[i], 0, 0,
>> +                           &entries[i].fence);
>>           if (!entries[i].fence) {
>> -            if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
>> -                continue;
>> -            } else {
>> -                ret = -EINVAL;
>> -                goto cleanup_entries;
>> -            }
>> +            ret = -EINVAL;
>> +            goto cleanup_entries;
>>           }
>>             if (dma_fence_is_signaled(entries[i].fence)) {
>> @@ -733,15 +1054,6 @@ static signed long 
>> drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
>>        * fallthough and try a 0 timeout wait!
>>        */
>>   -    if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
>> -        for (i = 0; i < count; ++i) {
>> -            drm_syncobj_fence_get_or_add_callback(syncobjs[i],
>> -                                  &entries[i].fence,
>> -                                  &entries[i].syncobj_cb,
>> -                                  syncobj_wait_syncobj_func);
>> -        }
>> -    }
>> -
>>       do {
>>           set_current_state(TASK_INTERRUPTIBLE);
>>   @@ -789,13 +1101,10 @@ static signed long 
>> drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
>>     cleanup_entries:
>>       for (i = 0; i < count; ++i) {
>> -        if (entries[i].syncobj_cb.func)
>> -            drm_syncobj_remove_callback(syncobjs[i],
>> -                            &entries[i].syncobj_cb);
>> +        dma_fence_put(entries[i].fence);
>>           if (entries[i].fence_cb.func)
>>               dma_fence_remove_callback(entries[i].fence,
>>                             &entries[i].fence_cb);
>> -        dma_fence_put(entries[i].fence);
>>       }
>>       kfree(entries);
>>   @@ -970,12 +1279,21 @@ drm_syncobj_reset_ioctl(struct drm_device 
>> *dev, void *data,
>>       if (ret < 0)
>>           return ret;
>>   -    for (i = 0; i < args->count_handles; i++)
>> -        drm_syncobj_replace_fence(syncobjs[i], 0, NULL);
>> -
>> +    for (i = 0; i < args->count_handles; i++) {
>> +        if (syncobjs[i]->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
>> +            DRM_ERROR("timeline syncobj cannot reset!\n");
>> +            ret = -EINVAL;
>> +            goto out;
>> +        }
>> +        drm_syncobj_timeline_fini(syncobjs[i],
>> +                      &syncobjs[i]->syncobj_timeline);
>> +        drm_syncobj_timeline_init(syncobjs[i],
>> +                      &syncobjs[i]->syncobj_timeline);
>> +    }
>> +out:
>>       drm_syncobj_array_free(syncobjs, args->count_handles);
>>   -    return 0;
>> +    return ret;
>>   }
>>     int
>> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c 
>> b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
>> index 0a8d2d64f380..579e91a5858b 100644
>> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
>> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
>> @@ -2137,7 +2137,9 @@ await_fence_array(struct i915_execbuffer *eb,
>>           if (!(flags & I915_EXEC_FENCE_WAIT))
>>               continue;
>>   -        fence = drm_syncobj_fence_get(syncobj);
>> +        drm_syncobj_search_fence(syncobj, 0,
>> +                     DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT,
>> +                     &fence);
>>           if (!fence)
>>               return -EINVAL;
>>   diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
>> index 425432b85a87..657c97dc25ec 100644
>> --- a/include/drm/drm_syncobj.h
>> +++ b/include/drm/drm_syncobj.h
>> @@ -30,6 +30,25 @@
>>     struct drm_syncobj_cb;
>>   +enum drm_syncobj_type {
>> +    DRM_SYNCOBJ_TYPE_NORMAL,
>> +    DRM_SYNCOBJ_TYPE_TIMELINE
>> +};
>> +
>> +struct drm_syncobj_timeline {
>> +    wait_queue_head_t    wq;
>> +    u64 timeline_context;
>> +    /**
>> +     * @timeline: syncobj timeline
>> +     */
>> +    u64 timeline;
>> +    u64 signal_point;
>> +
>> +
>> +    struct rb_root wait_pt_tree;
>> +    struct list_head signal_pt_list;
>> +};
>> +
>>   /**
>>    * struct drm_syncobj - sync object.
>>    *
>> @@ -41,19 +60,16 @@ struct drm_syncobj {
>>        */
>>       struct kref refcount;
>>       /**
>> -     * @fence:
>> -     * NULL or a pointer to the fence bound to this object.
>> -     *
>> -     * This field should not be used directly. Use 
>> drm_syncobj_fence_get()
>> -     * and drm_syncobj_replace_fence() instead.
>> +     * @type: indicate syncobj type
>>        */
>> -    struct dma_fence __rcu *fence;
>> +    enum drm_syncobj_type type;
>>       /**
>> -     * @cb_list: List of callbacks to call when the &fence gets 
>> replaced.
>> +     * @syncobj_timeline: timeline
>>        */
>> -    struct list_head cb_list;
>> +    struct drm_syncobj_timeline syncobj_timeline;
>> +
>>       /**
>> -     * @lock: Protects &cb_list and write-locks &fence.
>> +     * @lock: Protects timeline list and write-locks &fence.
>>        */
>>       spinlock_t lock;
>>       /**
>> @@ -62,25 +78,6 @@ struct drm_syncobj {
>>       struct file *file;
>>   };
>>   -typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,
>> -                   struct drm_syncobj_cb *cb);
>> -
>> -/**
>> - * struct drm_syncobj_cb - callback for drm_syncobj_add_callback
>> - * @node: used by drm_syncob_add_callback to append this struct to
>> - *      &drm_syncobj.cb_list
>> - * @func: drm_syncobj_func_t to call
>> - *
>> - * This struct will be initialized by drm_syncobj_add_callback, 
>> additional
>> - * data can be passed along by embedding drm_syncobj_cb in another 
>> struct.
>> - * The callback will get called the next time 
>> drm_syncobj_replace_fence is
>> - * called.
>> - */
>> -struct drm_syncobj_cb {
>> -    struct list_head node;
>> -    drm_syncobj_func_t func;
>> -};
>> -
>>   void drm_syncobj_free(struct kref *kref);
>>     /**
>> @@ -106,29 +103,6 @@ drm_syncobj_put(struct drm_syncobj *obj)
>>       kref_put(&obj->refcount, drm_syncobj_free);
>>   }
>>   -/**
>> - * drm_syncobj_fence_get - get a reference to a fence in a sync object
>> - * @syncobj: sync object.
>> - *
>> - * This acquires additional reference to &drm_syncobj.fence 
>> contained in @obj,
>> - * if not NULL. It is illegal to call this without already holding a 
>> reference.
>> - * No locks required.
>> - *
>> - * Returns:
>> - * Either the fence of @obj or NULL if there's none.
>> - */
>> -static inline struct dma_fence *
>> -drm_syncobj_fence_get(struct drm_syncobj *syncobj)
>> -{
>> -    struct dma_fence *fence;
>> -
>> -    rcu_read_lock();
>> -    fence = dma_fence_get_rcu_safe(&syncobj->fence);
>> -    rcu_read_unlock();
>> -
>> -    return fence;
>> -}
>> -
>>   struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
>>                        u32 handle);
>>   void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, u64 point,
>> @@ -142,5 +116,7 @@ int drm_syncobj_create(struct drm_syncobj 
>> **out_syncobj, uint32_t flags,
>>   int drm_syncobj_get_handle(struct drm_file *file_private,
>>                  struct drm_syncobj *syncobj, u32 *handle);
>>   int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);
>> +int drm_syncobj_search_fence(struct drm_syncobj *syncobj, u64 point,
>> +                 u64 flags, struct dma_fence **fence);
>>     #endif
>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>> index 300f336633f2..cebdb2541eb7 100644
>> --- a/include/uapi/drm/drm.h
>> +++ b/include/uapi/drm/drm.h
>> @@ -717,6 +717,7 @@ struct drm_prime_handle {
>>   struct drm_syncobj_create {
>>       __u32 handle;
>>   #define DRM_SYNCOBJ_CREATE_SIGNALED (1 << 0)
>> +#define DRM_SYNCOBJ_CREATE_TYPE_TIMELINE (1 << 1)
>>       __u32 flags;
>>   };
>



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