[PATCH 2/3] drm/vkms: Switch to shmem helpers

Thomas Zimmermann tzimmermann at suse.de
Mon Oct 12 11:22:20 UTC 2020


On Sat, 10 Oct 2020 01:21:55 +0200 Daniel Vetter <daniel.vetter at ffwll.ch>
wrote:

> Inspired by a patch by Chris Wilson for vgem. Plus this gives us vmap
> at the gem bo level, which we need for generic fbdev emulation.
> 
> Luckily shmem also tracks ->vaddr, so we just need to adjust the code
> all over a bit to make this fit.
> 
> Also wire up handle_to_fd, dunno why that was missing.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Maxime Ripard <mripard at kernel.org>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: David Airlie <airlied at linux.ie>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> Cc: Melissa Wen <melissa.srw at gmail.com>
> Cc: Haneen Mohammed <hamohammed.sa at gmail.com>
> ---
>  drivers/gpu/drm/Kconfig               |   1 +
>  drivers/gpu/drm/vkms/Makefile         |   1 -
>  drivers/gpu/drm/vkms/vkms_composer.c  |  17 +-
>  drivers/gpu/drm/vkms/vkms_drv.c       |  19 +-
>  drivers/gpu/drm/vkms/vkms_drv.h       |  26 ---
>  drivers/gpu/drm/vkms/vkms_gem.c       | 261 --------------------------
>  drivers/gpu/drm/vkms/vkms_plane.c     |  13 +-
>  drivers/gpu/drm/vkms/vkms_writeback.c |  17 +-
>  8 files changed, 32 insertions(+), 323 deletions(-)

Nice :)

>  delete mode 100644 drivers/gpu/drm/vkms/vkms_gem.c
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 9efb82caaa87..b796c118fc3b 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -287,6 +287,7 @@ config DRM_VKMS
>  	tristate "Virtual KMS (EXPERIMENTAL)"
>  	depends on DRM
>  	select DRM_KMS_HELPER
> +	select DRM_GEM_SHMEM_HELPER
>  	select CRC32
>  	default n
>  	help
> diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile
> index 333d3cead0e3..72f779cbfedd 100644
> --- a/drivers/gpu/drm/vkms/Makefile
> +++ b/drivers/gpu/drm/vkms/Makefile
> @@ -4,7 +4,6 @@ vkms-y := \
>  	vkms_plane.o \
>  	vkms_output.o \
>  	vkms_crtc.o \
> -	vkms_gem.o \
>  	vkms_composer.o \
>  	vkms_writeback.o
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index 33c031f27c2c..66c6842d70db 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -5,6 +5,7 @@
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
>  #include <drm/drm_vblank.h>
>  
>  #include "vkms_drv.h"
> @@ -129,15 +130,15 @@ static void compose_cursor(struct vkms_composer *cursor_composer,
>  			   void *vaddr_out)
>  {
>  	struct drm_gem_object *cursor_obj;
> -	struct vkms_gem_object *cursor_vkms_obj;
> +	struct drm_gem_shmem_object *cursor_shmem_obj;
>  
>  	cursor_obj = drm_gem_fb_get_obj(&cursor_composer->fb, 0);
> -	cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
> +	cursor_shmem_obj = to_drm_gem_shmem_obj(cursor_obj);
>  
> -	if (WARN_ON(!cursor_vkms_obj->vaddr))
> +	if (WARN_ON(!cursor_shmem_obj->vaddr))
>  		return;
>  
> -	blend(vaddr_out, cursor_vkms_obj->vaddr,
> +	blend(vaddr_out, cursor_shmem_obj->vaddr,
>  	      primary_composer, cursor_composer);
>  }
>  
> @@ -147,20 +148,20 @@ static int compose_planes(void **vaddr_out,
>  {
>  	struct drm_framebuffer *fb = &primary_composer->fb;
>  	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
> -	struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj);
> +	struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
>  
>  	if (!*vaddr_out) {
> -		*vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
> +		*vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
>  		if (!*vaddr_out) {
>  			DRM_ERROR("Cannot allocate memory for output frame.");
>  			return -ENOMEM;
>  		}
>  	}
>  
> -	if (WARN_ON(!vkms_obj->vaddr))
> +	if (WARN_ON(!shmem_obj->vaddr))
>  		return -EINVAL;
>  
> -	memcpy(*vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
> +	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
>  
>  	if (cursor_composer)
>  		compose_cursor(cursor_composer, primary_composer, *vaddr_out);
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index eb4007443706..6221e5040264 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -23,6 +23,7 @@
>  #include <drm/drm_ioctl.h>
>  #include <drm/drm_managed.h>
>  #include <drm/drm_probe_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
>  #include <drm/drm_vblank.h>
>  
>  #include "vkms_drv.h"
> @@ -39,17 +40,7 @@ bool enable_cursor = true;
>  module_param_named(enable_cursor, enable_cursor, bool, 0444);
>  MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");
>  
> -static const struct file_operations vkms_driver_fops = {
> -	.owner		= THIS_MODULE,
> -	.open		= drm_open,
> -	.mmap		= drm_gem_mmap,
> -	.unlocked_ioctl	= drm_ioctl,
> -	.compat_ioctl	= drm_compat_ioctl,
> -	.poll		= drm_poll,
> -	.read		= drm_read,
> -	.llseek		= no_llseek,
> -	.release	= drm_release,
> -};
> +DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
>  
>  static void vkms_release(struct drm_device *dev)
>  {
> @@ -91,9 +82,11 @@ static struct drm_driver vkms_driver = {
>  	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
>  	.release		= vkms_release,
>  	.fops			= &vkms_driver_fops,
> -	.dumb_create		= vkms_dumb_create,
> +	.dumb_create		= drm_gem_shmem_dumb_create,
>  	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
> -	.gem_prime_import_sg_table = vkms_prime_import_sg_table,
> +	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
> +	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
> +	.gem_prime_mmap		= drm_gem_prime_mmap,

Please see my comment on using drm_gem_shmem_create_object_cached() In any
case.

Acked-by: Thomas Zimmermann <tzimmermann at suse.de>

>   
>  	.name			= DRIVER_NAME,
>  	.desc			= DRIVER_DESC,
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 380a8f27e156..ef6482e3adea 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -88,14 +88,6 @@ struct vkms_device {
>  	struct vkms_output output;
>  };
>  
> -struct vkms_gem_object {
> -	struct drm_gem_object gem;
> -	struct mutex pages_lock; /* Page lock used in page fault handler */
> -	struct page **pages;
> -	unsigned int vmap_count;
> -	void *vaddr;
> -};
> -
>  #define drm_crtc_to_vkms_output(target) \
>  	container_of(target, struct vkms_output, crtc)
>  
> @@ -120,24 +112,6 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index);
>  struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
>  				  enum drm_plane_type type, int index);
>  
> -/* Gem stuff */
> -vm_fault_t vkms_gem_fault(struct vm_fault *vmf);
> -
> -int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
> -		     struct drm_mode_create_dumb *args);
> -
> -void vkms_gem_free_object(struct drm_gem_object *obj);
> -
> -int vkms_gem_vmap(struct drm_gem_object *obj);
> -
> -void vkms_gem_vunmap(struct drm_gem_object *obj);
> -
> -/* Prime */
> -struct drm_gem_object *
> -vkms_prime_import_sg_table(struct drm_device *dev,
> -			   struct dma_buf_attachment *attach,
> -			   struct sg_table *sg);
> -
>  /* CRC Support */
>  const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
>  					size_t *count);
> diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
> deleted file mode 100644
> index 19a0e260a4df..000000000000
> --- a/drivers/gpu/drm/vkms/vkms_gem.c
> +++ /dev/null
> @@ -1,261 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0+
> -
> -#include <linux/dma-buf.h>
> -#include <linux/shmem_fs.h>
> -#include <linux/vmalloc.h>
> -#include <drm/drm_prime.h>
> -
> -#include "vkms_drv.h"
> -
> -static const struct vm_operations_struct vkms_gem_vm_ops = {
> -	.fault = vkms_gem_fault,
> -	.open = drm_gem_vm_open,
> -	.close = drm_gem_vm_close,
> -};
> -
> -static const struct drm_gem_object_funcs vkms_gem_object_funcs = {
> -	.free = vkms_gem_free_object,
> -	.vm_ops = &vkms_gem_vm_ops,
> -};
> -
> -static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
> -						 u64 size)
> -{
> -	struct vkms_gem_object *obj;
> -	int ret;
> -
> -	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> -	if (!obj)
> -		return ERR_PTR(-ENOMEM);
> -
> -	obj->gem.funcs = &vkms_gem_object_funcs;
> -
> -	size = roundup(size, PAGE_SIZE);
> -	ret = drm_gem_object_init(dev, &obj->gem, size);
> -	if (ret) {
> -		kfree(obj);
> -		return ERR_PTR(ret);
> -	}
> -
> -	mutex_init(&obj->pages_lock);
> -
> -	return obj;
> -}
> -
> -void vkms_gem_free_object(struct drm_gem_object *obj)
> -{
> -	struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
> -						   gem);
> -
> -	WARN_ON(gem->pages);
> -	WARN_ON(gem->vaddr);
> -
> -	mutex_destroy(&gem->pages_lock);
> -	drm_gem_object_release(obj);
> -	kfree(gem);
> -}
> -
> -vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
> -{
> -	struct vm_area_struct *vma = vmf->vma;
> -	struct vkms_gem_object *obj = vma->vm_private_data;
> -	unsigned long vaddr = vmf->address;
> -	pgoff_t page_offset;
> -	loff_t num_pages;
> -	vm_fault_t ret = VM_FAULT_SIGBUS;
> -
> -	page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
> -	num_pages = DIV_ROUND_UP(obj->gem.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;
> -		struct address_space *mapping;
> -
> -		mapping = file_inode(obj->gem.filp)->i_mapping;
> -		page = shmem_read_mapping_page(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 struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
> -					      struct drm_file *file,
> -					      u32 *handle,
> -					      u64 size)
> -{
> -	struct vkms_gem_object *obj;
> -	int ret;
> -
> -	if (!file || !dev || !handle)
> -		return ERR_PTR(-EINVAL);
> -
> -	obj = __vkms_gem_create(dev, size);
> -	if (IS_ERR(obj))
> -		return ERR_CAST(obj);
> -
> -	ret = drm_gem_handle_create(file, &obj->gem, handle);
> -	if (ret)
> -		return ERR_PTR(ret);
> -
> -	return &obj->gem;
> -}
> -
> -int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
> -		     struct drm_mode_create_dumb *args)
> -{
> -	struct drm_gem_object *gem_obj;
> -	u64 pitch, size;
> -
> -	if (!args || !dev || !file)
> -		return -EINVAL;
> -
> -	pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
> -	size = pitch * args->height;
> -
> -	if (!size)
> -		return -EINVAL;
> -
> -	gem_obj = vkms_gem_create(dev, file, &args->handle, size);
> -	if (IS_ERR(gem_obj))
> -		return PTR_ERR(gem_obj);
> -
> -	args->size = gem_obj->size;
> -	args->pitch = pitch;
> -
> -	drm_gem_object_put(gem_obj);
> -
> -	DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
> -
> -	return 0;
> -}
> -
> -static struct page **_get_pages(struct vkms_gem_object *vkms_obj)
> -{
> -	struct drm_gem_object *gem_obj = &vkms_obj->gem;
> -
> -	if (!vkms_obj->pages) {
> -		struct page **pages = drm_gem_get_pages(gem_obj);
> -
> -		if (IS_ERR(pages))
> -			return pages;
> -
> -		if (cmpxchg(&vkms_obj->pages, NULL, pages))
> -			drm_gem_put_pages(gem_obj, pages, false, true);
> -	}
> -
> -	return vkms_obj->pages;
> -}
> -
> -void vkms_gem_vunmap(struct drm_gem_object *obj)
> -{
> -	struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
> -
> -	mutex_lock(&vkms_obj->pages_lock);
> -	if (vkms_obj->vmap_count < 1) {
> -		WARN_ON(vkms_obj->vaddr);
> -		WARN_ON(vkms_obj->pages);
> -		mutex_unlock(&vkms_obj->pages_lock);
> -		return;
> -	}
> -
> -	vkms_obj->vmap_count--;
> -
> -	if (vkms_obj->vmap_count == 0) {
> -		vunmap(vkms_obj->vaddr);
> -		vkms_obj->vaddr = NULL;
> -		drm_gem_put_pages(obj, vkms_obj->pages, false, true);
> -		vkms_obj->pages = NULL;
> -	}
> -
> -	mutex_unlock(&vkms_obj->pages_lock);
> -}
> -
> -int vkms_gem_vmap(struct drm_gem_object *obj)
> -{
> -	struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
> -	int ret = 0;
> -
> -	mutex_lock(&vkms_obj->pages_lock);
> -
> -	if (!vkms_obj->vaddr) {
> -		unsigned int n_pages = obj->size >> PAGE_SHIFT;
> -		struct page **pages = _get_pages(vkms_obj);
> -
> -		if (IS_ERR(pages)) {
> -			ret = PTR_ERR(pages);
> -			goto out;
> -		}
> -
> -		vkms_obj->vaddr = vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
> -		if (!vkms_obj->vaddr)
> -			goto err_vmap;
> -	}
> -
> -	vkms_obj->vmap_count++;
> -	goto out;
> -
> -err_vmap:
> -	ret = -ENOMEM;
> -	drm_gem_put_pages(obj, vkms_obj->pages, false, true);
> -	vkms_obj->pages = NULL;
> -out:
> -	mutex_unlock(&vkms_obj->pages_lock);
> -	return ret;
> -}
> -
> -struct drm_gem_object *
> -vkms_prime_import_sg_table(struct drm_device *dev,
> -			   struct dma_buf_attachment *attach,
> -			   struct sg_table *sg)
> -{
> -	struct vkms_gem_object *obj;
> -	int npages;
> -
> -	obj = __vkms_gem_create(dev, attach->dmabuf->size);
> -	if (IS_ERR(obj))
> -		return ERR_CAST(obj);
> -
> -	npages = PAGE_ALIGN(attach->dmabuf->size) / PAGE_SIZE;
> -	DRM_DEBUG_PRIME("Importing %d pages\n", npages);
> -
> -	obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
> -	if (!obj->pages) {
> -		vkms_gem_free_object(&obj->gem);
> -		return ERR_PTR(-ENOMEM);
> -	}
> -
> -	drm_prime_sg_to_page_addr_arrays(sg, obj->pages, NULL, npages);
> -	return &obj->gem;
> -}
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> index 6d31265a2ab7..9890137bcb8d 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.c
> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> @@ -5,6 +5,7 @@
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
>  #include <drm/drm_plane_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
>  
>  #include "vkms_drv.h"
>  
> @@ -145,15 +146,15 @@ static int vkms_prepare_fb(struct drm_plane *plane,
>  			   struct drm_plane_state *state)
>  {
>  	struct drm_gem_object *gem_obj;
> -	int ret;
> +	void *vaddr;
>  
>  	if (!state->fb)
>  		return 0;
>  
>  	gem_obj = drm_gem_fb_get_obj(state->fb, 0);
> -	ret = vkms_gem_vmap(gem_obj);
> -	if (ret)
> -		DRM_ERROR("vmap failed: %d\n", ret);
> +	vaddr = drm_gem_shmem_vmap(gem_obj);
> +	if (IS_ERR(vaddr))
> +		DRM_ERROR("vmap failed: %li\n", PTR_ERR(vaddr));
>  
>  	return drm_gem_fb_prepare_fb(plane, state);
>  }
> @@ -162,12 +163,14 @@ static void vkms_cleanup_fb(struct drm_plane *plane,
>  			    struct drm_plane_state *old_state)
>  {
>  	struct drm_gem_object *gem_obj;
> +	struct drm_gem_shmem_object *shmem_obj;
>  
>  	if (!old_state->fb)
>  		return;
>  
>  	gem_obj = drm_gem_fb_get_obj(old_state->fb, 0);
> -	vkms_gem_vunmap(gem_obj);
> +	shmem_obj = to_drm_gem_shmem_obj(drm_gem_fb_get_obj(old_state->fb, 0));
> +	drm_gem_shmem_vunmap(gem_obj, shmem_obj->vaddr);
>  }
>  
>  static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
> diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
> index 094fa4aa061d..26b903926872 100644
> --- a/drivers/gpu/drm/vkms/vkms_writeback.c
> +++ b/drivers/gpu/drm/vkms/vkms_writeback.c
> @@ -6,6 +6,7 @@
>  #include <drm/drm_probe_helper.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
>  
>  static const u32 vkms_wb_formats[] = {
>  	DRM_FORMAT_XRGB8888,
> @@ -63,22 +64,20 @@ static int vkms_wb_connector_get_modes(struct drm_connector *connector)
>  static int vkms_wb_prepare_job(struct drm_writeback_connector *wb_connector,
>  			       struct drm_writeback_job *job)
>  {
> -	struct vkms_gem_object *vkms_obj;
>  	struct drm_gem_object *gem_obj;
> -	int ret;
> +	void *vaddr;
>  
>  	if (!job->fb)
>  		return 0;
>  
>  	gem_obj = drm_gem_fb_get_obj(job->fb, 0);
> -	ret = vkms_gem_vmap(gem_obj);
> -	if (ret) {
> -		DRM_ERROR("vmap failed: %d\n", ret);
> -		return ret;
> +	vaddr = drm_gem_shmem_vmap(gem_obj);
> +	if (IS_ERR(vaddr)) {
> +		DRM_ERROR("vmap failed: %li\n", PTR_ERR(vaddr));
> +		return PTR_ERR(vaddr);
>  	}
>  
> -	vkms_obj = drm_gem_to_vkms_gem(gem_obj);
> -	job->priv = vkms_obj->vaddr;
> +	job->priv = vaddr;
>  
>  	return 0;
>  }
> @@ -93,7 +92,7 @@ static void vkms_wb_cleanup_job(struct drm_writeback_connector *connector,
>  		return;
>  
>  	gem_obj = drm_gem_fb_get_obj(job->fb, 0);
> -	vkms_gem_vunmap(gem_obj);
> +	drm_gem_shmem_vunmap(gem_obj, job->priv);
>  
>  	vkmsdev = drm_device_to_vkms_device(gem_obj->dev);
>  	vkms_set_composer(&vkmsdev->output, false);



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