On Wed, May 13, 2026 at 10:09 AM Boris Brezillon
<[email protected]> wrote:
>
> Now that we have guards for resv locks, we can use them to simplify the
> core. The only manual lock/unlock remaining are the ones in
> panthor_gem_try_evict_no_resv_wait(), because the lock/unlock are
> in different for_each() loop scopes.
>
> Signed-off-by: Boris Brezillon <[email protected]>
Reviewed-by: Chia-I Wu <[email protected]>
> ---
> drivers/gpu/drm/panthor/panthor_gem.c | 77
> ++++++++++++-----------------------
> drivers/gpu/drm/panthor/panthor_mmu.c | 16 ++++----
> 2 files changed, 32 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c
> b/drivers/gpu/drm/panthor/panthor_gem.c
> index a6fddc380e7d..94facdc8cfe1 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.c
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -339,13 +339,9 @@ panthor_gem_dev_map_get_sgt_locked(struct
> panthor_gem_object *bo)
> struct sg_table *
> panthor_gem_get_dev_sgt(struct panthor_gem_object *bo)
> {
> - struct sg_table *sgt;
> + guard(dma_resv)(bo->base.resv);
>
> - dma_resv_lock(bo->base.resv, NULL);
> - sgt = panthor_gem_dev_map_get_sgt_locked(bo);
> - dma_resv_unlock(bo->base.resv);
> -
> - return sgt;
> + return panthor_gem_dev_map_get_sgt_locked(bo);
> }
>
> static void
> @@ -497,7 +493,7 @@ panthor_gem_prime_begin_cpu_access(struct dma_buf
> *dma_buf,
> struct panthor_gem_object *bo = to_panthor_bo(obj);
> struct dma_buf_attachment *attach;
>
> - dma_resv_lock(obj->resv, NULL);
> + guard(dma_resv)(obj->resv);
> if (bo->dmap.sgt)
> dma_sync_sgtable_for_cpu(drm_dev_dma_dev(dev), bo->dmap.sgt,
> dir);
>
> @@ -510,7 +506,6 @@ panthor_gem_prime_begin_cpu_access(struct dma_buf
> *dma_buf,
> if (sgt)
> dma_sync_sgtable_for_cpu(attach->dev, sgt, dir);
> }
> - dma_resv_unlock(obj->resv);
>
> return 0;
> }
> @@ -524,7 +519,7 @@ panthor_gem_prime_end_cpu_access(struct dma_buf *dma_buf,
> struct panthor_gem_object *bo = to_panthor_bo(obj);
> struct dma_buf_attachment *attach;
>
> - dma_resv_lock(obj->resv, NULL);
> + guard(dma_resv)(obj->resv);
> list_for_each_entry(attach, &dma_buf->attachments, node) {
> struct sg_table *sgt = attach->priv;
>
> @@ -538,7 +533,6 @@ panthor_gem_prime_end_cpu_access(struct dma_buf *dma_buf,
> if (bo->dmap.sgt)
> dma_sync_sgtable_for_device(drm_dev_dma_dev(dev),
> bo->dmap.sgt, dir);
>
> - dma_resv_unlock(obj->resv);
> return 0;
> }
>
> @@ -625,19 +619,15 @@ static void panthor_gem_unpin_locked(struct
> drm_gem_object *obj)
>
> int panthor_gem_pin(struct panthor_gem_object *bo)
> {
> - int ret = 0;
> -
> if (drm_gem_is_imported(&bo->base))
> return 0;
>
> if (refcount_inc_not_zero(&bo->backing.pin_count))
> return 0;
>
> - dma_resv_lock(bo->base.resv, NULL);
> - ret = panthor_gem_backing_pin_locked(bo);
> - dma_resv_unlock(bo->base.resv);
> + guard(dma_resv)(bo->base.resv);
>
> - return ret;
> + return panthor_gem_backing_pin_locked(bo);
> }
>
> void panthor_gem_unpin(struct panthor_gem_object *bo)
> @@ -648,9 +638,8 @@ void panthor_gem_unpin(struct panthor_gem_object *bo)
> if (refcount_dec_not_one(&bo->backing.pin_count))
> return;
>
> - dma_resv_lock(bo->base.resv, NULL);
> + guard(dma_resv)(bo->base.resv);
> panthor_gem_backing_unpin_locked(bo);
> - dma_resv_unlock(bo->base.resv);
> }
>
> int panthor_gem_swapin_locked(struct panthor_gem_object *bo)
> @@ -759,13 +748,12 @@ static int panthor_gem_mmap(struct drm_gem_object *obj,
> struct vm_area_struct *v
> return -EINVAL;
>
> if (!refcount_inc_not_zero(&bo->cmap.mmap_count)) {
> - dma_resv_lock(obj->resv, NULL);
> + guard(dma_resv)(obj->resv);
> if (!refcount_inc_not_zero(&bo->cmap.mmap_count)) {
> refcount_set(&bo->cmap.mmap_count, 1);
> guard(mutex)(&bo->base.gpuva.lock);
> panthor_gem_update_reclaim_state_locked(bo, NULL);
> }
> - dma_resv_unlock(obj->resv);
> }
>
> vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
> @@ -814,18 +802,12 @@ static vm_fault_t nonblocking_page_setup(struct
> vm_fault *vmf,
> {
> struct vm_area_struct *vma = vmf->vma;
> struct panthor_gem_object *bo = to_panthor_bo(vma->vm_private_data);
> - vm_fault_t ret;
>
> - if (!dma_resv_trylock(bo->base.resv))
> + ACQUIRE(dma_resv_try, resv_guard)(bo->base.resv);
> + if (ACQUIRE_ERR(dma_resv_try, &resv_guard) || !bo->backing.pages)
> return VM_FAULT_RETRY;
>
> - if (bo->backing.pages)
> - ret = insert_page(vmf, order, bo->backing.pages[page_offset]);
> - else
> - ret = VM_FAULT_RETRY;
> -
> - dma_resv_unlock(bo->base.resv);
> - return ret;
> + return insert_page(vmf, order, bo->backing.pages[page_offset]);
> }
>
> static vm_fault_t blocking_page_setup(struct vm_fault *vmf, unsigned int
> order,
> @@ -835,8 +817,8 @@ static vm_fault_t blocking_page_setup(struct vm_fault
> *vmf, unsigned int order,
> vm_fault_t ret;
> int err;
>
> - err = dma_resv_lock_interruptible(bo->base.resv, NULL);
> - if (err)
> + ACQUIRE(dma_resv_intr, resv_guard)(bo->base.resv);
> + if (ACQUIRE_ERR(dma_resv_intr, &resv_guard))
> return mmap_lock_held ? VM_FAULT_NOPAGE : VM_FAULT_RETRY;
>
> err = panthor_gem_backing_get_pages_locked(bo);
> @@ -857,8 +839,6 @@ static vm_fault_t blocking_page_setup(struct vm_fault
> *vmf, unsigned int order,
> ret = VM_FAULT_RETRY;
> }
>
> - dma_resv_unlock(bo->base.resv);
> -
> return ret;
> }
>
> @@ -932,12 +912,12 @@ static void panthor_gem_vm_close(struct vm_area_struct
> *vma)
> if (refcount_dec_not_one(&bo->cmap.mmap_count))
> goto out;
>
> - dma_resv_lock(bo->base.resv, NULL);
> - if (refcount_dec_and_test(&bo->cmap.mmap_count)) {
> - guard(mutex)(&bo->base.gpuva.lock);
> - panthor_gem_update_reclaim_state_locked(bo, NULL);
> + scoped_guard(dma_resv, bo->base.resv) {
> + if (refcount_dec_and_test(&bo->cmap.mmap_count)) {
> + guard(mutex)(&bo->base.gpuva.lock);
> + panthor_gem_update_reclaim_state_locked(bo, NULL);
> + }
> }
> - dma_resv_unlock(bo->base.resv);
>
> out:
> drm_gem_object_put(&bo->base);
> @@ -1161,21 +1141,18 @@ panthor_gem_sync(struct drm_gem_object *obj, u32 type,
> if (size == 0)
> return 0;
>
> - ret = dma_resv_lock_interruptible(bo->base.resv, NULL);
> + ACQUIRE(dma_resv_intr, resv_guard)(bo->base.resv);
> + ret = ACQUIRE_ERR(dma_resv_intr, &resv_guard);
> if (ret)
> return ret;
>
> /* If there's no pages, there's no point pulling those back, bail out
> early. */
> - if (!bo->backing.pages) {
> - ret = 0;
> - goto out_unlock;
> - }
> + if (!bo->backing.pages)
> + return 0;
>
> sgt = panthor_gem_dev_map_get_sgt_locked(bo);
> - if (IS_ERR(sgt)) {
> - ret = PTR_ERR(sgt);
> - goto out_unlock;
> - }
> + if (IS_ERR(sgt))
> + return PTR_ERR(sgt);
>
> for_each_sgtable_dma_sg(sgt, sgl, count) {
> if (size == 0)
> @@ -1219,11 +1196,7 @@ panthor_gem_sync(struct drm_gem_object *obj, u32 type,
> dma_sync_single_for_cpu(dma_dev, paddr, len,
> DMA_FROM_DEVICE);
> }
>
> - ret = 0;
> -
> -out_unlock:
> - dma_resv_unlock(bo->base.resv);
> - return ret;
> + return 0;
> }
>
> /**
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
> b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 157eef286cb9..ab9a77e6a145 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1118,10 +1118,10 @@ static void panthor_vm_bo_free(struct drm_gpuvm_bo
> *vm_bo)
> /* We couldn't call this when we unlinked, because the resv lock can't
> * be taken in the dma signalling path, so call it now.
> */
> - dma_resv_lock(bo->base.resv, NULL);
> - scoped_guard(mutex, &bo->base.gpuva.lock)
> + scoped_guard(dma_resv, bo->base.resv) {
> + guard(mutex)(&bo->base.gpuva.lock);
> panthor_gem_update_reclaim_state_locked(bo, NULL);
> - dma_resv_unlock(bo->base.resv);
> + }
>
> kfree(vm_bo);
> }
> @@ -1342,16 +1342,14 @@ static int panthor_vm_prepare_map_op_ctx(struct
> panthor_vm_op_ctx *op_ctx,
>
> /* Insert BO into the extobj list last, when we know nothing can
> fail. */
> if (bo->base.resv != panthor_vm_resv(vm)) {
> - dma_resv_lock(panthor_vm_resv(vm), NULL);
> + guard(dma_resv)(panthor_vm_resv(vm));
> drm_gpuvm_bo_extobj_add(op_ctx->map.vm_bo);
> - dma_resv_unlock(panthor_vm_resv(vm));
> }
>
> /* And finally update the BO state. */
> - dma_resv_lock(bo->base.resv, NULL);
> - scoped_guard(mutex, &bo->base.gpuva.lock)
> - panthor_gem_update_reclaim_state_locked(bo, NULL);
> - dma_resv_unlock(bo->base.resv);
> + guard(dma_resv)(bo->base.resv);
> + guard(mutex)(&bo->base.gpuva.lock);
> + panthor_gem_update_reclaim_state_locked(bo, NULL);
>
> return 0;
>
>
> --
> 2.54.0
>
