[PATCH 4/6] drm/panthor: Use guards for resv locking
From: Boris Brezillon
Date: Wed May 13 2026 - 13:30:26 EST
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 <boris.brezillon@xxxxxxxxxxxxx>
---
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