[PATCH v4 2/9] dma-fence: Use a flag for 64-bit seqnos
Christian König
christian.koenig at amd.com
Thu May 15 13:15:07 UTC 2025
Hey drm-misc maintainers,
can you guys please backmerge drm-next into drm-misc-next?
I want to push this patch here but it depends on changes which are partially in drm-next and partially in drm-misc-next.
Thanks in advance,
Christian.
On 5/15/25 11:49, Tvrtko Ursulin wrote:
> With the goal of reducing the need for drivers to touch (and dereference)
> fence->ops, we move the 64-bit seqnos flag from struct dma_fence_ops to
> the fence->flags.
>
> Drivers which were setting this flag are changed to use new
> dma_fence_init64() instead of dma_fence_init().
>
> v2:
> * Streamlined init and added kerneldoc.
> * Rebase for amdgpu userq which landed since.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
> Reviewed-by: Christian König <christian.koenig at amd.com> # v1
> ---
> drivers/dma-buf/dma-fence-chain.c | 5 +-
> drivers/dma-buf/dma-fence.c | 69 ++++++++++++++-----
> .../drm/amd/amdgpu/amdgpu_eviction_fence.c | 7 +-
> .../gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 5 +-
> .../gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c | 5 +-
> include/linux/dma-fence.h | 14 ++--
> 6 files changed, 64 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c
> index 90424f23fd73..a8a90acf4f34 100644
> --- a/drivers/dma-buf/dma-fence-chain.c
> +++ b/drivers/dma-buf/dma-fence-chain.c
> @@ -218,7 +218,6 @@ static void dma_fence_chain_set_deadline(struct dma_fence *fence,
> }
>
> const struct dma_fence_ops dma_fence_chain_ops = {
> - .use_64bit_seqno = true,
> .get_driver_name = dma_fence_chain_get_driver_name,
> .get_timeline_name = dma_fence_chain_get_timeline_name,
> .enable_signaling = dma_fence_chain_enable_signaling,
> @@ -262,8 +261,8 @@ void dma_fence_chain_init(struct dma_fence_chain *chain,
> seqno = max(prev->seqno, seqno);
> }
>
> - dma_fence_init(&chain->base, &dma_fence_chain_ops,
> - &chain->lock, context, seqno);
> + dma_fence_init64(&chain->base, &dma_fence_chain_ops, &chain->lock,
> + context, seqno);
>
> /*
> * Chaining dma_fence_chain container together is only allowed through
> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> index f0cdd3e99d36..705b59787731 100644
> --- a/drivers/dma-buf/dma-fence.c
> +++ b/drivers/dma-buf/dma-fence.c
> @@ -989,24 +989,9 @@ void dma_fence_describe(struct dma_fence *fence, struct seq_file *seq)
> }
> EXPORT_SYMBOL(dma_fence_describe);
>
> -/**
> - * dma_fence_init - Initialize a custom fence.
> - * @fence: the fence to initialize
> - * @ops: the dma_fence_ops for operations on this fence
> - * @lock: the irqsafe spinlock to use for locking this fence
> - * @context: the execution context this fence is run on
> - * @seqno: a linear increasing sequence number for this context
> - *
> - * Initializes an allocated fence, the caller doesn't have to keep its
> - * refcount after committing with this fence, but it will need to hold a
> - * refcount again if &dma_fence_ops.enable_signaling gets called.
> - *
> - * context and seqno are used for easy comparison between fences, allowing
> - * to check which fence is later by simply using dma_fence_later().
> - */
> -void
> -dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> - spinlock_t *lock, u64 context, u64 seqno)
> +static void
> +__dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> + spinlock_t *lock, u64 context, u64 seqno, unsigned long flags)
> {
> BUG_ON(!lock);
> BUG_ON(!ops || !ops->get_driver_name || !ops->get_timeline_name);
> @@ -1017,9 +1002,55 @@ dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> fence->lock = lock;
> fence->context = context;
> fence->seqno = seqno;
> - fence->flags = 0UL;
> + fence->flags = flags;
> fence->error = 0;
>
> trace_dma_fence_init(fence);
> }
> +
> +/**
> + * dma_fence_init - Initialize a custom fence.
> + * @fence: the fence to initialize
> + * @ops: the dma_fence_ops for operations on this fence
> + * @lock: the irqsafe spinlock to use for locking this fence
> + * @context: the execution context this fence is run on
> + * @seqno: a linear increasing sequence number for this context
> + *
> + * Initializes an allocated fence, the caller doesn't have to keep its
> + * refcount after committing with this fence, but it will need to hold a
> + * refcount again if &dma_fence_ops.enable_signaling gets called.
> + *
> + * context and seqno are used for easy comparison between fences, allowing
> + * to check which fence is later by simply using dma_fence_later().
> + */
> +void
> +dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> + spinlock_t *lock, u64 context, u64 seqno)
> +{
> + __dma_fence_init(fence, ops, lock, context, seqno, 0UL);
> +}
> EXPORT_SYMBOL(dma_fence_init);
> +
> +/**
> + * dma_fence_init64 - Initialize a custom fence with 64-bit seqno support.
> + * @fence: the fence to initialize
> + * @ops: the dma_fence_ops for operations on this fence
> + * @lock: the irqsafe spinlock to use for locking this fence
> + * @context: the execution context this fence is run on
> + * @seqno: a linear increasing sequence number for this context
> + *
> + * Initializes an allocated fence, the caller doesn't have to keep its
> + * refcount after committing with this fence, but it will need to hold a
> + * refcount again if &dma_fence_ops.enable_signaling gets called.
> + *
> + * Context and seqno are used for easy comparison between fences, allowing
> + * to check which fence is later by simply using dma_fence_later().
> + */
> +void
> +dma_fence_init64(struct dma_fence *fence, const struct dma_fence_ops *ops,
> + spinlock_t *lock, u64 context, u64 seqno)
> +{
> + __dma_fence_init(fence, ops, lock, context, seqno,
> + BIT(DMA_FENCE_FLAG_SEQNO64_BIT));
> +}
> +EXPORT_SYMBOL(dma_fence_init64);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
> index 1a7469543db5..79713421bffe 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
> @@ -134,7 +134,6 @@ static bool amdgpu_eviction_fence_enable_signaling(struct dma_fence *f)
> }
>
> static const struct dma_fence_ops amdgpu_eviction_fence_ops = {
> - .use_64bit_seqno = true,
> .get_driver_name = amdgpu_eviction_fence_get_driver_name,
> .get_timeline_name = amdgpu_eviction_fence_get_timeline_name,
> .enable_signaling = amdgpu_eviction_fence_enable_signaling,
> @@ -160,9 +159,9 @@ amdgpu_eviction_fence_create(struct amdgpu_eviction_fence_mgr *evf_mgr)
> ev_fence->evf_mgr = evf_mgr;
> get_task_comm(ev_fence->timeline_name, current);
> spin_lock_init(&ev_fence->lock);
> - dma_fence_init(&ev_fence->base, &amdgpu_eviction_fence_ops,
> - &ev_fence->lock, evf_mgr->ev_fence_ctx,
> - atomic_inc_return(&evf_mgr->ev_fence_seq));
> + dma_fence_init64(&ev_fence->base, &amdgpu_eviction_fence_ops,
> + &ev_fence->lock, evf_mgr->ev_fence_ctx,
> + atomic_inc_return(&evf_mgr->ev_fence_seq));
> return ev_fence;
> }
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> index 029cb24c28b3..5e92d00a591f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> @@ -239,8 +239,8 @@ static int amdgpu_userq_fence_create(struct amdgpu_usermode_queue *userq,
> fence = &userq_fence->base;
> userq_fence->fence_drv = fence_drv;
>
> - dma_fence_init(fence, &amdgpu_userq_fence_ops, &userq_fence->lock,
> - fence_drv->context, seq);
> + dma_fence_init64(fence, &amdgpu_userq_fence_ops, &userq_fence->lock,
> + fence_drv->context, seq);
>
> amdgpu_userq_fence_driver_get(fence_drv);
> dma_fence_get(fence);
> @@ -334,7 +334,6 @@ static void amdgpu_userq_fence_release(struct dma_fence *f)
> }
>
> static const struct dma_fence_ops amdgpu_userq_fence_ops = {
> - .use_64bit_seqno = true,
> .get_driver_name = amdgpu_userq_fence_get_driver_name,
> .get_timeline_name = amdgpu_userq_fence_get_timeline_name,
> .signaled = amdgpu_userq_fence_signaled,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
> index 51cddfa3f1e8..5d26797356a3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
> @@ -71,7 +71,6 @@ static void amdgpu_tlb_fence_work(struct work_struct *work)
> }
>
> static const struct dma_fence_ops amdgpu_tlb_fence_ops = {
> - .use_64bit_seqno = true,
> .get_driver_name = amdgpu_tlb_fence_get_driver_name,
> .get_timeline_name = amdgpu_tlb_fence_get_timeline_name
> };
> @@ -101,8 +100,8 @@ void amdgpu_vm_tlb_fence_create(struct amdgpu_device *adev, struct amdgpu_vm *vm
> INIT_WORK(&f->work, amdgpu_tlb_fence_work);
> spin_lock_init(&f->lock);
>
> - dma_fence_init(&f->base, &amdgpu_tlb_fence_ops, &f->lock,
> - vm->tlb_fence_context, atomic64_read(&vm->tlb_seq));
> + dma_fence_init64(&f->base, &amdgpu_tlb_fence_ops, &f->lock,
> + vm->tlb_fence_context, atomic64_read(&vm->tlb_seq));
>
> /* TODO: We probably need a separate wq here */
> dma_fence_get(&f->base);
> diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
> index 48b5202c531d..a34a0dcdc446 100644
> --- a/include/linux/dma-fence.h
> +++ b/include/linux/dma-fence.h
> @@ -97,6 +97,7 @@ struct dma_fence {
> };
>
> enum dma_fence_flag_bits {
> + DMA_FENCE_FLAG_SEQNO64_BIT,
> DMA_FENCE_FLAG_SIGNALED_BIT,
> DMA_FENCE_FLAG_TIMESTAMP_BIT,
> DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
> @@ -124,14 +125,6 @@ struct dma_fence_cb {
> *
> */
> struct dma_fence_ops {
> - /**
> - * @use_64bit_seqno:
> - *
> - * True if this dma_fence implementation uses 64bit seqno, false
> - * otherwise.
> - */
> - bool use_64bit_seqno;
> -
> /**
> * @get_driver_name:
> *
> @@ -262,6 +255,9 @@ struct dma_fence_ops {
> void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> spinlock_t *lock, u64 context, u64 seqno);
>
> +void dma_fence_init64(struct dma_fence *fence, const struct dma_fence_ops *ops,
> + spinlock_t *lock, u64 context, u64 seqno);
> +
> void dma_fence_release(struct kref *kref);
> void dma_fence_free(struct dma_fence *fence);
> void dma_fence_describe(struct dma_fence *fence, struct seq_file *seq);
> @@ -454,7 +450,7 @@ static inline bool __dma_fence_is_later(struct dma_fence *fence, u64 f1, u64 f2)
> * 32bit sequence numbers. Use a 64bit compare when the driver says to
> * do so.
> */
> - if (fence->ops->use_64bit_seqno)
> + if (test_bit(DMA_FENCE_FLAG_SEQNO64_BIT, &fence->flags))
> return f1 > f2;
>
> return (int)(lower_32_bits(f1) - lower_32_bits(f2)) > 0;
More information about the Intel-gfx
mailing list