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

On Fri, Feb 26, 2021 at 02:51:58PM +0100, Thomas Zimmermann wrote:

Hi

Am 26.02.21 um 14:30 schrieb Daniel Vetter:

...

On Fri, Feb 26, 2021 at 10:19 AM Thomas Zimmermann tzimmermann@suse.de wrote:

...

Hi

Am 25.02.21 um 11:23 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.

v2: Review from Thomas:

• sort #include
• drop more dead code that I didn't spot somehow

v3: select DRM_GEM_SHMEM_HELPER to make it build (intel-gfx-ci)

Since you're working on it, could you move the config item into a Kconfig file under vgem?

We have a lot of drivers still without their own Kconfig. I thought we're only doing that for drivers which have multiple options, or otherwise would clutter up the main drm/Kconfig file?

Not opposed to this, just feels like if we do this, should do it for all of them.

I didn't know that there was a rule for how to handle this. I just didn't like to have driver config rules in the main Kconfig file.

I don't think it is an actual rule, just how the driver Kconfig files started out.

But yeah, maybe let's change this consistently in a separate patchset.

Yeah I looked, we should also put all the driver files at the bottom, and maybe sort them alphabetically or something like that. It's a bit a mess right now. -Daniel

Best regards Thomas

...

-Daniel

...

Best regards Thomas

...

Cc: Thomas Zimmermann tzimmermann@suse.de Acked-by: Thomas Zimmermann tzimmermann@suse.de 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/Kconfig | 1 + drivers/gpu/drm/vgem/vgem_drv.c | 340 +------------------------------- 2 files changed, 4 insertions(+), 337 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 8e73311de583..94e4ac830283 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -274,6 +274,7 @@ source "drivers/gpu/drm/kmb/Kconfig" config DRM_VGEM tristate "Virtual GEM provider" depends on DRM

• select DRM_GEM_SHMEM_HELPER
   help
     Choose this option to get a virtual graphics memory manager,
     as used by Mesa's software renderer for enhanced performance.
  

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index a0e75f1d5d01..b1b3a5ffc542 100644 --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -38,6 +38,7 @@

#include <drm/drm_drv.h> #include <drm/drm_file.h> +#include <drm/drm_gem_shmem_helper.h> #include <drm/drm_ioctl.h> #include <drm/drm_managed.h> #include <drm/drm_prime.h> @@ -50,87 +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) -{

• struct vm_area_struct *vma = vmf->vma;
  

• struct drm_vgem_gem_object *obj = vma->vm_private_data;
  

• /* We don't use vmf->pgoff since that has the fake offset */
  

• unsigned long vaddr = vmf->address;
  

• vm_fault_t ret = VM_FAULT_SIGBUS;
  

• loff_t num_pages;
  

• pgoff_t page_offset;
  

• page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
  

• num_pages = DIV_ROUND_UP(obj->base.size, PAGE_SIZE);
  

• if (page_offset >= num_pages)
  

•         return VM_FAULT_SIGBUS;
  

• mutex_lock(&obj->pages_lock);
  

• if (obj->pages) {
  

•         get_page(obj->pages[page_offset]);
  

•         vmf->page = obj->pages[page_offset];
  

•         ret = 0;
  

• }
  

• mutex_unlock(&obj->pages_lock);
  

• if (ret) {
  

•         struct page *page;
  

•         page = shmem_read_mapping_page(
  

•                                 file_inode(obj->base.filp)->i_mapping,
  

•                                 page_offset);
  

•         if (!IS_ERR(page)) {
  

•                 vmf->page = page;
  

•                 ret = 0;
  

•         } else switch (PTR_ERR(page)) {
  

•                 case -ENOSPC:
  

•                 case -ENOMEM:
  

•                         ret = VM_FAULT_OOM;
  

•                         break;
  

•                 case -EBUSY:
  

•                         ret = VM_FAULT_RETRY;
  

•                         break;
  

•                 case -EFAULT:
  

•                 case -EINVAL:
  

•                         ret = VM_FAULT_SIGBUS;
  

•                         break;
  

•                 default:
  

•                         WARN_ON(PTR_ERR(page));
  

•                         ret = VM_FAULT_SIGBUS;
  

•                         break;
  

•         }
  

• }
  

• return ret;
  

-}

-static const struct vm_operations_struct vgem_gem_vm_ops = {

• .fault = vgem_gem_fault,
  

• .open = drm_gem_vm_open,
  

• .close = drm_gem_vm_close,
  

-};

• static int vgem_open(struct drm_device *dev, struct drm_file *file) { struct vgem_file *vfile;

@@ -159,265 +84,12 @@ 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 +99,7 @@ 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,
  
  

-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer

-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer