On Wed, Apr 01, 2026 at 03:48:53PM +0200, Boris Brezillon wrote: > This will be used to order things by reclaimability. > > v2: > - Fix refcounting > > v3: > - Fix refcounting (again) > > v4: > - Collect R-b > > v5: > - Collect R-b > > v6: > - Warn on is_imported() (not supposed to happen since mmap is > redirected to the dmabuf layer) instead of adding a conditional > in panthor_gem_vm_open() > > v7: > - No changes > > Signed-off-by: Boris Brezillon <[email protected]> > Reviewed-by: Steven Price <[email protected]>
Reviewed-by: Liviu Dudau <[email protected]> Best regards, Liviu > --- > drivers/gpu/drm/panthor/panthor_gem.c | 42 +++++++++++++++++++++++++-- > drivers/gpu/drm/panthor/panthor_gem.h | 3 ++ > 2 files changed, 43 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c > b/drivers/gpu/drm/panthor/panthor_gem.c > index d9c3a71da29b..eb139759beda 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -488,6 +488,7 @@ static void panthor_gem_print_info(struct drm_printer *p, > unsigned int indent, > drm_printf_indent(p, indent, "vmap_use_count=%u\n", > refcount_read(&bo->cmap.vaddr_use_count)); > drm_printf_indent(p, indent, "vaddr=%p\n", bo->cmap.vaddr); > + drm_printf_indent(p, indent, "mmap_count=%u\n", > refcount_read(&bo->cmap.mmap_count)); > } > > static int panthor_gem_pin_locked(struct drm_gem_object *obj) > @@ -604,6 +605,13 @@ static int panthor_gem_mmap(struct drm_gem_object *obj, > struct vm_area_struct *v > if (is_cow_mapping(vma->vm_flags)) > return -EINVAL; > > + if (!refcount_inc_not_zero(&bo->cmap.mmap_count)) { > + dma_resv_lock(obj->resv, NULL); > + if (!refcount_inc_not_zero(&bo->cmap.mmap_count)) > + refcount_set(&bo->cmap.mmap_count, 1); > + dma_resv_unlock(obj->resv); > + } > + > vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); > vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); > if (should_map_wc(bo)) > @@ -740,13 +748,43 @@ static vm_fault_t panthor_gem_fault(struct vm_fault > *vmf) > return panthor_gem_any_fault(vmf, 0); > } > > +static void panthor_gem_vm_open(struct vm_area_struct *vma) > +{ > + struct panthor_gem_object *bo = to_panthor_bo(vma->vm_private_data); > + > + drm_WARN_ON(bo->base.dev, drm_gem_is_imported(&bo->base)); > + drm_WARN_ON(bo->base.dev, !refcount_inc_not_zero(&bo->cmap.mmap_count)); > + > + drm_gem_vm_open(vma); > +} > + > +static void panthor_gem_vm_close(struct vm_area_struct *vma) > +{ > + struct panthor_gem_object *bo = to_panthor_bo(vma->vm_private_data); > + > + if (drm_gem_is_imported(&bo->base)) > + goto out; > + > + 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)) { > + /* Nothing to do, pages are reclaimed lazily. */ > + } > + dma_resv_unlock(bo->base.resv); > + > +out: > + drm_gem_object_put(&bo->base); > +} > + > static const struct vm_operations_struct panthor_gem_vm_ops = { > .fault = panthor_gem_fault, > #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP > .huge_fault = panthor_gem_any_fault, > #endif > - .open = drm_gem_vm_open, > - .close = drm_gem_vm_close, > + .open = panthor_gem_vm_open, > + .close = panthor_gem_vm_close, > }; > > static const struct drm_gem_object_funcs panthor_gem_funcs = { > diff --git a/drivers/gpu/drm/panthor/panthor_gem.h > b/drivers/gpu/drm/panthor/panthor_gem.h > index b66478c9590c..c0a18dca732c 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.h > +++ b/drivers/gpu/drm/panthor/panthor_gem.h > @@ -80,6 +80,9 @@ struct panthor_gem_cpu_map { > > /** @vaddr_use_count: Number of active vmap() requests on this GEM */ > refcount_t vaddr_use_count; > + > + /** @mmap_count: Number of active mmap() requests on this GEM */ > + refcount_t mmap_count; > }; > > /** > -- > 2.53.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯
