[PATCH] drm/vgem: use shmem helpers
Thomas Zimmermann
tzimmermann at suse.de
Fri Feb 26 09:19:10 UTC 2021
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?
Best regards
Thomas
>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Acked-by: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: John Stultz <john.stultz at linaro.org>
> Cc: Sumit Semwal <sumit.semwal at linaro.org>
> Cc: "Christian König" <christian.koenig at amd.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> Cc: Melissa Wen <melissa.srw at gmail.com>
> Cc: Chris Wilson <chris at 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
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