Am 08.11.18 um 17:04 schrieb Eric Anholt:
> Daniel suggested I submit this, since we're still seeing regressions
> from it. This is a revert to before 48197bc564c7 ("drm: add syncobj
> timeline support v9") and its followon fixes.
This is a harmless false positive from lockdep, Chouming and I are
already working on a fix.
Christian.
>
> Fixes this on first V3D testcase execution:
>
> [ 48.767088] ============================================
> [ 48.772410] WARNING: possible recursive locking detected
> [ 48.777739] 4.19.0-rc6+ #489 Not tainted
> [ 48.781668] --------------------------------------------
> [ 48.786993] shader_runner/3284 is trying to acquire lock:
> [ 48.792408] ce309d7f (&(&array->lock)->rlock){....}, at:
> dma_fence_add_callback+0x30/0x23c
> [ 48.800714]
> [ 48.800714] but task is already holding lock:
> [ 48.806559] c5952bd3 (&(&array->lock)->rlock){....}, at:
> dma_fence_add_callback+0x30/0x23c
> [ 48.814862]
> [ 48.814862] other info that might help us debug this:
> [ 48.821410] Possible unsafe locking scenario:
> [ 48.821410]
> [ 48.827338] CPU0
> [ 48.829788] ----
> [ 48.832239] lock(&(&array->lock)->rlock);
> [ 48.836434] lock(&(&array->lock)->rlock);
> [ 48.840640]
> [ 48.840640] *** DEADLOCK ***
> [ 48.840640]
> [ 48.846582] May be due to missing lock nesting notation
> [ 130.763560] 1 lock held by cts-runner/3270:
> [ 130.767745] #0: 7834b793 (&(&array->lock)->rlock){-...}, at:
> dma_fence_add_callback+0x30/0x23c
> [ 130.776461]
> stack backtrace:
> [ 130.780825] CPU: 1 PID: 3270 Comm: cts-runner Not tainted 4.19.0-rc6+ #486
> [ 130.787706] Hardware name: Broadcom STB (Flattened Device Tree)
> [ 130.793645] [<c021269c>] (unwind_backtrace) from [<c020db1c>]
> (show_stack+0x10/0x14)
> [ 130.801404] [<c020db1c>] (show_stack) from [<c0c2c4b0>]
> (dump_stack+0xa8/0xd4)
> [ 130.808642] [<c0c2c4b0>] (dump_stack) from [<c0281a84>]
> (__lock_acquire+0x848/0x1a68)
> [ 130.816483] [<c0281a84>] (__lock_acquire) from [<c02835d8>]
> (lock_acquire+0xd8/0x22c)
> [ 130.824326] [<c02835d8>] (lock_acquire) from [<c0c49948>]
> (_raw_spin_lock_irqsave+0x54/0x68)
> [ 130.832777] [<c0c49948>] (_raw_spin_lock_irqsave) from [<c086bf54>]
> (dma_fence_add_callback+0x30/0x23c)
> [ 130.842183] [<c086bf54>] (dma_fence_add_callback) from [<c086d4c8>]
> (dma_fence_array_enable_signaling+0x58/0xec)
> [ 130.852371] [<c086d4c8>] (dma_fence_array_enable_signaling) from
> [<c086c00c>] (dma_fence_add_callback+0xe8/0x23c)
> [ 130.862647] [<c086c00c>] (dma_fence_add_callback) from [<c06d8774>]
> (drm_syncobj_wait_ioctl+0x518/0x614)
> [ 130.872143] [<c06d8774>] (drm_syncobj_wait_ioctl) from [<c06b8458>]
> (drm_ioctl_kernel+0xb0/0xf0)
> [ 130.880940] [<c06b8458>] (drm_ioctl_kernel) from [<c06b8818>]
> (drm_ioctl+0x1d8/0x390)
> [ 130.888782] [<c06b8818>] (drm_ioctl) from [<c03a4510>]
> (do_vfs_ioctl+0xb0/0x8ac)
> [ 130.896187] [<c03a4510>] (do_vfs_ioctl) from [<c03a4d40>]
> (ksys_ioctl+0x34/0x60)
> [ 130.903593] [<c03a4d40>] (ksys_ioctl) from [<c0201000>]
> (ret_fast_syscall+0x0/0x28)
>
> Cc: Chunming Zhou <david1.z...@amd.com>
> Cc: Christian König <christian.koe...@amd.com>
> Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
> Signed-off-by: Eric Anholt <e...@anholt.net>
> ---
> drivers/gpu/drm/drm_syncobj.c | 359 +++++++---------------------------
> include/drm/drm_syncobj.h | 73 ++++---
> 2 files changed, 105 insertions(+), 327 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index da8175d9c6ff..e2c5b3ca4824 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -56,9 +56,6 @@
> #include "drm_internal.h"
> #include <drm/drm_syncobj.h>
>
> -/* merge normal syncobj to timeline syncobj, the point interval is 1 */
> -#define DRM_SYNCOBJ_BINARY_POINT 1
> -
> struct drm_syncobj_stub_fence {
> struct dma_fence base;
> spinlock_t lock;
> @@ -74,29 +71,7 @@ static const struct dma_fence_ops
> drm_syncobj_stub_fence_ops = {
> .get_timeline_name = drm_syncobj_stub_fence_get_name,
> };
>
> -struct drm_syncobj_signal_pt {
> - struct dma_fence_array *fence_array;
> - u64 value;
> - struct list_head list;
> -};
> -
> -static DEFINE_SPINLOCK(signaled_fence_lock);
> -static struct dma_fence signaled_fence;
>
> -static struct dma_fence *drm_syncobj_get_stub_fence(void)
> -{
> - spin_lock(&signaled_fence_lock);
> - if (!signaled_fence.ops) {
> - dma_fence_init(&signaled_fence,
> - &drm_syncobj_stub_fence_ops,
> - &signaled_fence_lock,
> - 0, 0);
> - dma_fence_signal_locked(&signaled_fence);
> - }
> - spin_unlock(&signaled_fence_lock);
> -
> - return dma_fence_get(&signaled_fence);
> -}
> /**
> * drm_syncobj_find - lookup and reference a sync object.
> * @file_private: drm file private pointer
> @@ -123,27 +98,6 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file
> *file_private,
> }
> EXPORT_SYMBOL(drm_syncobj_find);
>
> -static struct dma_fence *
> -drm_syncobj_find_signal_pt_for_point(struct drm_syncobj *syncobj,
> - uint64_t point)
> -{
> - struct drm_syncobj_signal_pt *signal_pt;
> -
> - if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) &&
> - (point <= syncobj->timeline))
> - return drm_syncobj_get_stub_fence();
> -
> - list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) {
> - if (point > signal_pt->value)
> - continue;
> - if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) &&
> - (point != signal_pt->value))
> - continue;
> - return dma_fence_get(&signal_pt->fence_array->base);
> - }
> - return NULL;
> -}
> -
> static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
> struct drm_syncobj_cb *cb,
> drm_syncobj_func_t func)
> @@ -152,158 +106,53 @@ static void drm_syncobj_add_callback_locked(struct
> drm_syncobj *syncobj,
> list_add_tail(&cb->node, &syncobj->cb_list);
> }
>
> -static void 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 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)
> {
> - u64 pt_value = 0;
> -
> - WARN_ON(*fence);
> -
> - if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) {
> - /*BINARY syncobj always wait on last pt */
> - pt_value = syncobj->signal_point;
> + int ret;
>
> - if (pt_value == 0)
> - pt_value += DRM_SYNCOBJ_BINARY_POINT;
> - }
> + *fence = drm_syncobj_fence_get(syncobj);
> + if (*fence)
> + return 1;
>
> - mutex_lock(&syncobj->cb_mutex);
> - spin_lock(&syncobj->pt_lock);
> - *fence = drm_syncobj_find_signal_pt_for_point(syncobj, pt_value);
> - spin_unlock(&syncobj->pt_lock);
> - if (!*fence)
> + 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);
> - mutex_unlock(&syncobj->cb_mutex);
> -}
> -
> -static void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
> - struct drm_syncobj_cb *cb)
> -{
> - mutex_lock(&syncobj->cb_mutex);
> - list_del_init(&cb->node);
> - mutex_unlock(&syncobj->cb_mutex);
> -}
> + ret = 0;
> + }
> + spin_unlock(&syncobj->lock);
>
> -static void drm_syncobj_init(struct drm_syncobj *syncobj)
> -{
> - spin_lock(&syncobj->pt_lock);
> - syncobj->timeline_context = dma_fence_context_alloc(1);
> - syncobj->timeline = 0;
> - syncobj->signal_point = 0;
> - init_waitqueue_head(&syncobj->wq);
> -
> - INIT_LIST_HEAD(&syncobj->signal_pt_list);
> - spin_unlock(&syncobj->pt_lock);
> + return ret;
> }
>
> -static void drm_syncobj_fini(struct drm_syncobj *syncobj)
> +void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
> + struct drm_syncobj_cb *cb,
> + drm_syncobj_func_t func)
> {
> - struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
> -
> - spin_lock(&syncobj->pt_lock);
> - list_for_each_entry_safe(signal_pt, tmp,
> - &syncobj->signal_pt_list, list) {
> - list_del(&signal_pt->list);
> - dma_fence_put(&signal_pt->fence_array->base);
> - kfree(signal_pt);
> - }
> - spin_unlock(&syncobj->pt_lock);
> + spin_lock(&syncobj->lock);
> + drm_syncobj_add_callback_locked(syncobj, cb, func);
> + spin_unlock(&syncobj->lock);
> }
>
> -static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj,
> - struct dma_fence *fence,
> - u64 point)
> +void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
> + struct drm_syncobj_cb *cb)
> {
> - 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;
> - int num_fences = 0;
> - int ret = 0, i;
> -
> - if (!signal_pt)
> - return -ENOMEM;
> - if (!fence)
> - goto out;
> -
> - fences = kmalloc_array(sizeof(void *), 2, GFP_KERNEL);
> - if (!fences) {
> - ret = -ENOMEM;
> - 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->pt_lock);
> - if (!list_empty(&syncobj->signal_pt_list)) {
> - tail_pt = list_last_entry(&syncobj->signal_pt_list,
> - struct drm_syncobj_signal_pt,
> list);
> - fences[num_fences++] =
> - dma_fence_get(&tail_pt->fence_array->base);
> - }
> - spin_unlock(&syncobj->pt_lock);
> - }
> - signal_pt->fence_array = dma_fence_array_create(num_fences, fences,
> -
> syncobj->timeline_context,
> - point, false);
> - if (!signal_pt->fence_array) {
> - ret = -ENOMEM;
> - goto fail;
> - }
> -
> - spin_lock(&syncobj->pt_lock);
> - if (syncobj->signal_point >= point) {
> - DRM_WARN("A later signal is ready!");
> - spin_unlock(&syncobj->pt_lock);
> - goto exist;
> - }
> - signal_pt->value = point;
> - list_add_tail(&signal_pt->list, &syncobj->signal_pt_list);
> - syncobj->signal_point = point;
> - spin_unlock(&syncobj->pt_lock);
> - wake_up_all(&syncobj->wq);
> -
> - return 0;
> -exist:
> - dma_fence_put(&signal_pt->fence_array->base);
> -fail:
> - for (i = 0; i < num_fences; i++)
> - dma_fence_put(fences[i]);
> - kfree(fences);
> -out:
> - kfree(signal_pt);
> - return ret;
> + spin_lock(&syncobj->lock);
> + list_del_init(&cb->node);
> + spin_unlock(&syncobj->lock);
> }
>
> -static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj)
> -{
> - struct drm_syncobj_signal_pt *signal_pt, *tmp, *tail_pt;
> -
> - spin_lock(&syncobj->pt_lock);
> - tail_pt = list_last_entry(&syncobj->signal_pt_list,
> - struct drm_syncobj_signal_pt,
> - list);
> - list_for_each_entry_safe(signal_pt, tmp,
> - &syncobj->signal_pt_list, list) {
> - if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY &&
> - signal_pt == tail_pt)
> - continue;
> - if (dma_fence_is_signaled(&signal_pt->fence_array->base)) {
> - syncobj->timeline = signal_pt->value;
> - list_del(&signal_pt->list);
> - dma_fence_put(&signal_pt->fence_array->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->pt_lock);
> -}
> /**
> * drm_syncobj_replace_fence - replace fence in a sync object.
> * @syncobj: Sync object to replace fence in
> @@ -316,30 +165,28 @@ void drm_syncobj_replace_fence(struct drm_syncobj
> *syncobj,
> u64 point,
> struct dma_fence *fence)
> {
> - u64 pt_value = point;
> -
> - drm_syncobj_garbage_collection(syncobj);
> - if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) {
> - if (!fence) {
> - drm_syncobj_fini(syncobj);
> - drm_syncobj_init(syncobj);
> - return;
> - }
> - pt_value = syncobj->signal_point +
> - DRM_SYNCOBJ_BINARY_POINT;
> - }
> - drm_syncobj_create_signal_pt(syncobj, fence, pt_value);
> - if (fence) {
> - struct drm_syncobj_cb *cur, *tmp;
> - LIST_HEAD(cb_list);
> + struct dma_fence *old_fence;
> + struct drm_syncobj_cb *cur, *tmp;
> +
> + if (fence)
> + dma_fence_get(fence);
> +
> + spin_lock(&syncobj->lock);
>
> - mutex_lock(&syncobj->cb_mutex);
> + 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);
> }
> - mutex_unlock(&syncobj->cb_mutex);
> }
> +
> + spin_unlock(&syncobj->lock);
> +
> + dma_fence_put(old_fence);
> }
> EXPORT_SYMBOL(drm_syncobj_replace_fence);
>
> @@ -362,64 +209,6 @@ static int drm_syncobj_assign_null_handle(struct
> drm_syncobj *syncobj)
> return 0;
> }
>
> -static int
> -drm_syncobj_point_get(struct drm_syncobj *syncobj, u64 point, u64 flags,
> - struct dma_fence **fence)
> -{
> - int ret = 0;
> -
> - if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
> - ret = wait_event_interruptible(syncobj->wq,
> - point <= syncobj->signal_point);
> - if (ret < 0)
> - return ret;
> - }
> - spin_lock(&syncobj->pt_lock);
> - *fence = drm_syncobj_find_signal_pt_for_point(syncobj, point);
> - if (!*fence)
> - ret = -EINVAL;
> - spin_unlock(&syncobj->pt_lock);
> - return ret;
> -}
> -
> -/**
> - * drm_syncobj_search_fence - lookup and reference the fence in a sync
> object or
> - * in a timeline point
> - * @syncobj: sync object pointer
> - * @point: timeline point
> - * @flags: DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT or not
> - * @fence: out parameter for the fence
> - *
> - * if flags is DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT, the function will
> block
> - * here until specific timeline points is reached.
> - * if not, you need a submit thread and block in userspace until all future
> - * timeline points have materialized, only then you can submit to the kernel,
> - * otherwise, function will fail to return fence.
> - *
> - * Returns 0 on success or a negative error value on failure. On success
> @fence
> - * contains a reference to the fence, which must be released by calling
> - * dma_fence_put().
> - */
> -int drm_syncobj_search_fence(struct drm_syncobj *syncobj, u64 point,
> - u64 flags, struct dma_fence **fence)
> -{
> - u64 pt_value = point;
> -
> - if (!syncobj)
> - return -ENOENT;
> -
> - drm_syncobj_garbage_collection(syncobj);
> - if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) {
> - /*BINARY syncobj always wait on last pt */
> - pt_value = syncobj->signal_point;
> -
> - if (pt_value == 0)
> - pt_value += DRM_SYNCOBJ_BINARY_POINT;
> - }
> - return drm_syncobj_point_get(syncobj, pt_value, flags, fence);
> -}
> -EXPORT_SYMBOL(drm_syncobj_search_fence);
> -
> /**
> * drm_syncobj_find_fence - lookup and reference the fence in a sync object
> * @file_private: drm file private pointer
> @@ -429,7 +218,7 @@ EXPORT_SYMBOL(drm_syncobj_search_fence);
> * @fence: out parameter for the fence
> *
> * This is just a convenience function that combines drm_syncobj_find() and
> - * drm_syncobj_lookup_fence().
> + * drm_syncobj_fence_get().
> *
> * Returns 0 on success or a negative error value on failure. On success
> @fence
> * contains a reference to the fence, which must be released by calling
> @@ -440,11 +229,16 @@ int drm_syncobj_find_fence(struct drm_file
> *file_private,
> struct dma_fence **fence)
> {
> struct drm_syncobj *syncobj = drm_syncobj_find(file_private, handle);
> - int ret;
> + int ret = 0;
>
> - ret = drm_syncobj_search_fence(syncobj, point, flags, fence);
> - if (syncobj)
> - drm_syncobj_put(syncobj);
> + if (!syncobj)
> + return -ENOENT;
> +
> + *fence = drm_syncobj_fence_get(syncobj);
> + if (!*fence) {
> + ret = -EINVAL;
> + }
> + drm_syncobj_put(syncobj);
> return ret;
> }
> EXPORT_SYMBOL(drm_syncobj_find_fence);
> @@ -460,7 +254,7 @@ void drm_syncobj_free(struct kref *kref)
> struct drm_syncobj *syncobj = container_of(kref,
> struct drm_syncobj,
> refcount);
> - drm_syncobj_fini(syncobj);
> + drm_syncobj_replace_fence(syncobj, 0, NULL);
> kfree(syncobj);
> }
> EXPORT_SYMBOL(drm_syncobj_free);
> @@ -489,13 +283,7 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj,
> uint32_t flags,
>
> kref_init(&syncobj->refcount);
> INIT_LIST_HEAD(&syncobj->cb_list);
> - spin_lock_init(&syncobj->pt_lock);
> - mutex_init(&syncobj->cb_mutex);
> - if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE)
> - syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE;
> - else
> - syncobj->type = DRM_SYNCOBJ_TYPE_BINARY;
> - drm_syncobj_init(syncobj);
> + spin_lock_init(&syncobj->lock);
>
> if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
> ret = drm_syncobj_assign_null_handle(syncobj);
> @@ -778,8 +566,7 @@ drm_syncobj_create_ioctl(struct drm_device *dev, void
> *data,
> return -EOPNOTSUPP;
>
> /* no valid flags yet */
> - if (args->flags & ~(DRM_SYNCOBJ_CREATE_SIGNALED |
> - DRM_SYNCOBJ_CREATE_TYPE_TIMELINE))
> + if (args->flags & ~DRM_SYNCOBJ_CREATE_SIGNALED)
> return -EINVAL;
>
> return drm_syncobj_create_as_handle(file_private,
> @@ -872,8 +659,9 @@ static void syncobj_wait_syncobj_func(struct drm_syncobj
> *syncobj,
> struct syncobj_wait_entry *wait =
> container_of(cb, struct syncobj_wait_entry, syncobj_cb);
>
> - drm_syncobj_search_fence(syncobj, 0, 0, &wait->fence);
> -
> + /* 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);
> }
>
> @@ -899,8 +687,7 @@ 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;
> - drm_syncobj_search_fence(syncobjs[i], 0, 0,
> - &entries[i].fence);
> + entries[i].fence = drm_syncobj_fence_get(syncobjs[i]);
> if (!entries[i].fence) {
> if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
> continue;
> @@ -931,9 +718,6 @@ static signed long drm_syncobj_array_wait_timeout(struct
> drm_syncobj **syncobjs,
>
> if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
> for (i = 0; i < count; ++i) {
> - if (entries[i].fence)
> - continue;
> -
> drm_syncobj_fence_get_or_add_callback(syncobjs[i],
> &entries[i].fence,
>
> &entries[i].syncobj_cb,
> @@ -1165,13 +949,12 @@ 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_fini(syncobjs[i]);
> - drm_syncobj_init(syncobjs[i]);
> - }
> + for (i = 0; i < args->count_handles; i++)
> + drm_syncobj_replace_fence(syncobjs[i], 0, NULL);
> +
> drm_syncobj_array_free(syncobjs, args->count_handles);
>
> - return ret;
> + return 0;
> }
>
> int
> diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
> index 29244cbcd05e..2eda44def639 100644
> --- a/include/drm/drm_syncobj.h
> +++ b/include/drm/drm_syncobj.h
> @@ -30,15 +30,10 @@
>
> struct drm_syncobj_cb;
>
> -enum drm_syncobj_type {
> - DRM_SYNCOBJ_TYPE_BINARY,
> - DRM_SYNCOBJ_TYPE_TIMELINE
> -};
> -
> /**
> * struct drm_syncobj - sync object.
> *
> - * This structure defines a generic sync object which is timeline based.
> + * This structure defines a generic sync object which wraps a &dma_fence.
> */
> struct drm_syncobj {
> /**
> @@ -46,42 +41,21 @@ struct drm_syncobj {
> */
> struct kref refcount;
> /**
> - * @type: indicate syncobj type
> - */
> - enum drm_syncobj_type type;
> - /**
> - * @wq: wait signal operation work queue
> - */
> - wait_queue_head_t wq;
> - /**
> - * @timeline_context: fence context used by timeline
> + * @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.
> */
> - u64 timeline_context;
> + struct dma_fence __rcu *fence;
> /**
> - * @timeline: syncobj timeline value, which indicates point is signaled.
> + * @cb_list: List of callbacks to call when the &fence gets replaced.
> */
> - u64 timeline;
> - /**
> - * @signal_point: which indicates the latest signaler point.
> - */
> - u64 signal_point;
> - /**
> - * @signal_pt_list: signaler point list.
> - */
> - struct list_head signal_pt_list;
> -
> - /**
> - * @cb_list: List of callbacks to call when the &fence gets replaced.
> - */
> struct list_head cb_list;
> /**
> - * @pt_lock: Protects pt list.
> + * @lock: Protects &cb_list and write-locks &fence.
> */
> - spinlock_t pt_lock;
> - /**
> - * @cb_mutex: Protects syncobj cb list.
> - */
> - struct mutex cb_mutex;
> + spinlock_t lock;
> /**
> * @file: A file backing for this syncobj.
> */
> @@ -94,7 +68,7 @@ typedef void (*drm_syncobj_func_t)(struct drm_syncobj
> *syncobj,
> /**
> * 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
> + * &drm_syncobj.cb_list
> * @func: drm_syncobj_func_t to call
> *
> * This struct will be initialized by drm_syncobj_add_callback, additional
> @@ -132,6 +106,29 @@ 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,
> @@ -145,7 +142,5 @@ 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
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