Re: [PATCH 2/2] drm/vgem: use shmem helpers

Hi

Am 23.02.21 um 11:59 schrieb Daniel Vetter:

Aside from deleting lots of code the real motivation here is to switch the mmap over to VM_PFNMAP, to be more consistent with what real gpu drivers do. They're all VM_PFNMP, which means get_user_pages doesn't work, and even if you try and there's a struct page behind that, touching it and mucking around with its refcount can upset drivers real bad.

Cc: John Stultz john.stultz@linaro.org Cc: Sumit Semwal sumit.semwal@linaro.org Cc: "Christian König" christian.koenig@amd.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Melissa Wen melissa.srw@gmail.com Cc: Chris Wilson chris@chris-wilson.co.uk

---

drivers/gpu/drm/vgem/vgem_drv.c | 280 +------------------------------- 1 file changed, 3 insertions(+), 277 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index a0e75f1d5d01..88b3d125a610 100644 --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -40,6 +40,7 @@ #include <drm/drm_file.h> #include <drm/drm_ioctl.h> #include <drm/drm_managed.h> +#include <drm/drm_gem_shmem_helper.h>

This should be between file.h and ioctl.h

#include <drm/drm_prime.h>

#include "vgem_drv.h" @@ -50,27 +51,11 @@ #define DRIVER_MAJOR 1 #define DRIVER_MINOR 0

-static const struct drm_gem_object_funcs vgem_gem_object_funcs;

• static struct vgem_device { struct drm_device drm; struct platform_device *platform; } *vgem_device;

-static void vgem_gem_free_object(struct drm_gem_object *obj) -{

• struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);
• kvfree(vgem_obj->pages);
• mutex_destroy(&vgem_obj->pages_lock);
• if (obj->import_attach)

• drm_prime_gem_destroy(obj, vgem_obj->table);
  

• drm_gem_object_release(obj);
• kfree(vgem_obj);

-}

• static vm_fault_t vgem_gem_fault(struct vm_fault *vmf)

From a quick grep it looks like you should be able to remove this function and vgam_gem_vm_ops as well.

The rest of the patch looks good to me.

Acked-by: Thomas Zimmermann tzimmermann@suse.de

{ struct vm_area_struct *vma = vmf->vma; @@ -159,265 +144,12 @@ static void vgem_postclose(struct drm_device *dev, struct drm_file *file) kfree(vfile); }

-static struct drm_vgem_gem_object *__vgem_gem_create(struct drm_device *dev,

• 				unsigned long size)
  

-{

• struct drm_vgem_gem_object *obj;
• int ret;
• obj = kzalloc(sizeof(*obj), GFP_KERNEL);
• if (!obj)

• return ERR_PTR(-ENOMEM);
  

• obj->base.funcs = &vgem_gem_object_funcs;
• ret = drm_gem_object_init(dev, &obj->base, roundup(size, PAGE_SIZE));
• if (ret) {

• kfree(obj);
  

• return ERR_PTR(ret);
  

• }
• mutex_init(&obj->pages_lock);
• return obj;

-}

-static void __vgem_gem_destroy(struct drm_vgem_gem_object *obj) -{

• drm_gem_object_release(&obj->base);
• kfree(obj);

-}

-static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,

• 			      struct drm_file *file,
  

• 			      unsigned int *handle,
  

• 			      unsigned long size)
  

-{

• struct drm_vgem_gem_object *obj;
• int ret;
• obj = __vgem_gem_create(dev, size);
• if (IS_ERR(obj))

• return ERR_CAST(obj);
  

• ret = drm_gem_handle_create(file, &obj->base, handle);
• if (ret) {

• drm_gem_object_put(&obj->base);
  

• return ERR_PTR(ret);
  

• }
• return &obj->base;

-}

-static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,

• 		struct drm_mode_create_dumb *args)
  

-{

• struct drm_gem_object *gem_object;
• u64 pitch, size;
• pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
• size = args->height * pitch;
• if (size == 0)

• return -EINVAL;
  

• gem_object = vgem_gem_create(dev, file, &args->handle, size);
• if (IS_ERR(gem_object))

• return PTR_ERR(gem_object);
  

• args->size = gem_object->size;
• args->pitch = pitch;
• drm_gem_object_put(gem_object);
• DRM_DEBUG("Created object of size %llu\n", args->size);
• return 0;

-}

• static struct drm_ioctl_desc vgem_ioctls[] = { DRM_IOCTL_DEF_DRV(VGEM_FENCE_ATTACH, vgem_fence_attach_ioctl, DRM_RENDER_ALLOW), DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW), };

-static int vgem_mmap(struct file *filp, struct vm_area_struct *vma) -{

• unsigned long flags = vma->vm_flags;
• int ret;
• ret = drm_gem_mmap(filp, vma);
• if (ret)

• return ret;
  

• /* Keep the WC mmaping set by drm_gem_mmap() but our pages

• * are ordinary and not special.
  

• */
  

• vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
• return 0;

-}

-static const struct file_operations vgem_driver_fops = {

• .owner = THIS_MODULE,
• .open = drm_open,
• .mmap = vgem_mmap,
• .poll = drm_poll,
• .read = drm_read,
• .unlocked_ioctl = drm_ioctl,
• .compat_ioctl = drm_compat_ioctl,
• .release = drm_release,

-};

-static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo) -{

• mutex_lock(&bo->pages_lock);
• if (bo->pages_pin_count++ == 0) {

• struct page **pages;
  

• pages = drm_gem_get_pages(&bo->base);
  

• if (IS_ERR(pages)) {
  

• 	bo->pages_pin_count--;
  

• 	mutex_unlock(&bo->pages_lock);
  

• 	return pages;
  

• }
  

• bo->pages = pages;
  

• }
• mutex_unlock(&bo->pages_lock);
• return bo->pages;

-}

-static void vgem_unpin_pages(struct drm_vgem_gem_object *bo) -{

• mutex_lock(&bo->pages_lock);
• if (--bo->pages_pin_count == 0) {

• drm_gem_put_pages(&bo->base, bo->pages, true, true);
  

• bo->pages = NULL;
  

• }
• mutex_unlock(&bo->pages_lock);

-}

-static int vgem_prime_pin(struct drm_gem_object *obj) -{

• struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
• long n_pages = obj->size >> PAGE_SHIFT;
• struct page **pages;
• pages = vgem_pin_pages(bo);
• if (IS_ERR(pages))

• return PTR_ERR(pages);
  

• /* Flush the object from the CPU cache so that importers can rely

• * on coherent indirect access via the exported dma-address.
  

• */
  

• drm_clflush_pages(pages, n_pages);
• return 0;

-}

-static void vgem_prime_unpin(struct drm_gem_object *obj) -{

• struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
• vgem_unpin_pages(bo);

-}

-static struct sg_table *vgem_prime_get_sg_table(struct drm_gem_object *obj) -{

• struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
• return drm_prime_pages_to_sg(obj->dev, bo->pages, bo->base.size >> PAGE_SHIFT);

-}

-static struct drm_gem_object* vgem_prime_import(struct drm_device *dev,

• 				struct dma_buf *dma_buf)
  

-{

• struct vgem_device *vgem = container_of(dev, typeof(*vgem), drm);
• return drm_gem_prime_import_dev(dev, dma_buf, &vgem->platform->dev);

-}

-static struct drm_gem_object *vgem_prime_import_sg_table(struct drm_device *dev,

• 	struct dma_buf_attachment *attach, struct sg_table *sg)
  

-{

• struct drm_vgem_gem_object *obj;
• int npages;
• obj = __vgem_gem_create(dev, attach->dmabuf->size);
• if (IS_ERR(obj))

• return ERR_CAST(obj);
  

• npages = PAGE_ALIGN(attach->dmabuf->size) / PAGE_SIZE;
• obj->table = sg;
• obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
• if (!obj->pages) {

• __vgem_gem_destroy(obj);
  

• return ERR_PTR(-ENOMEM);
  

• }
• obj->pages_pin_count++; /* perma-pinned */
• drm_prime_sg_to_page_array(obj->table, obj->pages, npages);
• return &obj->base;

-}

-static int vgem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map) -{

• struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
• long n_pages = obj->size >> PAGE_SHIFT;
• struct page **pages;
• void *vaddr;
• pages = vgem_pin_pages(bo);
• if (IS_ERR(pages))

• return PTR_ERR(pages);
  

• vaddr = vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL));
• if (!vaddr)

• return -ENOMEM;
  

• dma_buf_map_set_vaddr(map, vaddr);
• return 0;

-}

-static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map) -{

• struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
• vunmap(map->vaddr);
• vgem_unpin_pages(bo);

-}

-static int vgem_prime_mmap(struct drm_gem_object *obj,

• 	   struct vm_area_struct *vma)
  

-{

• int ret;
• if (obj->size < vma->vm_end - vma->vm_start)

• return -EINVAL;
  

• if (!obj->filp)

• return -ENODEV;
  

• ret = call_mmap(obj->filp, vma);
• if (ret)

• return ret;
  

• vma_set_file(vma, obj->filp);
• vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
• vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
• return 0;

-}

-static const struct drm_gem_object_funcs vgem_gem_object_funcs = {

• .free = vgem_gem_free_object,
• .pin = vgem_prime_pin,
• .unpin = vgem_prime_unpin,
• .get_sg_table = vgem_prime_get_sg_table,
• .vmap = vgem_prime_vmap,
• .vunmap = vgem_prime_vunmap,
• .vm_ops = &vgem_gem_vm_ops,

-}; +DEFINE_DRM_GEM_FOPS(vgem_driver_fops);

static const struct drm_driver vgem_driver = { .driver_features = DRIVER_GEM | DRIVER_RENDER, @@ -427,13 +159,7 @@ static const struct drm_driver vgem_driver = { .num_ioctls = ARRAY_SIZE(vgem_ioctls), .fops = &vgem_driver_fops,

• .dumb_create = vgem_gem_dumb_create,
• .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
• .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
• .gem_prime_import = vgem_prime_import,
• .gem_prime_import_sg_table = vgem_prime_import_sg_table,
• .gem_prime_mmap = vgem_prime_mmap,

• DRM_GEM_SHMEM_DRIVER_OPS,

  .name = DRIVER_NAME, .desc = DRIVER_DESC,