[PATCH 1/2] drm: Add library for shmem backed GEM objects

[PATCH 1/2] drm: Add library for shmem backed GEM objects

[Eric Anholt]

From: Noralf Trønnes <noralf@tronnes.org>

This adds a library for shmem backed GEM objects.

v6:
- Fix uninitialized variable issue in an error path (anholt).
- Add a drm_gem_shmem_vm_open() to the fops to get proper refcounting
  of the pages (anholt).

v5:
- Drop drm_gem_shmem_prime_mmap() (Daniel Vetter)
- drm_gem_shmem_mmap(): Subtract drm_vma_node_start() to get the real
  vma->vm_pgoff
- drm_gem_shmem_fault(): Use vmf->pgoff now that vma->vm_pgoff is correct

v4:
- Drop cache modes (Thomas Hellstrom)
- Add a GEM attached vtable

v3:
- Grammar (Sam Ravnborg)
- s/drm_gem_shmem_put_pages_unlocked/drm_gem_shmem_put_pages_locked/
  (Sam Ravnborg)
- Add debug output in error path (Sam Ravnborg)

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
---
 Documentation/gpu/drm-kms-helpers.rst  |  12 +
 drivers/gpu/drm/Kconfig                |   6 +
 drivers/gpu/drm/Makefile               |   1 +
 drivers/gpu/drm/drm_gem_shmem_helper.c | 563 +++++++++++++++++++++++++
 include/drm/drm_gem_shmem_helper.h     | 153 +++++++
 5 files changed, 735 insertions(+)
 create mode 100644 drivers/gpu/drm/drm_gem_shmem_helper.c
 create mode 100644 include/drm/drm_gem_shmem_helper.h

diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index 4b4dc236ef6f..8305d3566928 100644
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -335,3 +335,15 @@ Legacy CRTC/Modeset Helper Functions Reference
 
 .. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
    :export:
+
+SHMEM GEM Helper Reference
+==========================
+
+.. kernel-doc:: drivers/gpu/drm/drm_gem_shmem_helper.c
+   :doc: overview
+
+.. kernel-doc:: include/drm/drm_gem_shmem_helper.h
+   :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_gem_shmem_helper.c
+   :export:
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 4385f00e1d05..0dedbc040c77 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -177,6 +177,12 @@ config DRM_KMS_CMA_HELPER
 	help
 	  Choose this if you need the KMS CMA helper functions
 
+config DRM_GEM_SHMEM_HELPER
+	bool
+	depends on DRM
+	help
+	  Choose this if you need the GEM shmem helper functions
+
 config DRM_VM
 	bool
 	depends on DRM && MMU
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 7c88f12096c5..e5559fbf23af 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -25,6 +25,7 @@ drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
 drm-$(CONFIG_DRM_VM) += drm_vm.o
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
+drm-$(CONFIG_DRM_GEM_SHMEM_HELPER) += drm_gem_shmem_helper.o
 drm-$(CONFIG_PCI) += ati_pcigart.o
 drm-$(CONFIG_DRM_PANEL) += drm_panel.o
 drm-$(CONFIG_OF) += drm_of.o
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
new file mode 100644
index 000000000000..527b0b27de22
--- /dev/null
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -0,0 +1,563 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 Noralf Trønnes
+ */
+
+#include <linux/dma-buf.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/shmem_fs.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_prime.h>
+#include <drm/drm_print.h>
+
+/**
+ * DOC: overview
+ *
+ * This library provides helpers for GEM objects backed by shmem buffers
+ * allocated using anonymous pageable memory.
+ */
+
+static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
+	.free = drm_gem_shmem_free_object,
+	.print_info = drm_gem_shmem_print_info,
+	.pin = drm_gem_shmem_pin,
+	.unpin = drm_gem_shmem_unpin,
+	.get_sg_table = drm_gem_shmem_get_sg_table,
+	.vmap = drm_gem_shmem_vmap,
+	.vunmap = drm_gem_shmem_vunmap,
+	.vm_ops = &drm_gem_shmem_vm_ops,
+};
+
+/**
+ * drm_gem_shmem_create - Allocate an object with the given size
+ * @dev: DRM device
+ * @size: Size of the object to allocate
+ *
+ * This function creates a shmem GEM object.
+ *
+ * Returns:
+ * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
+ * error code on failure.
+ */
+struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
+{
+	struct drm_gem_shmem_object *shmem;
+	struct drm_gem_object *obj;
+	int ret;
+
+	size = PAGE_ALIGN(size);
+
+	if (dev->driver->gem_create_object)
+		obj = dev->driver->gem_create_object(dev, size);
+	else
+		obj = kzalloc(sizeof(*shmem), GFP_KERNEL);
+	if (!obj)
+		return ERR_PTR(-ENOMEM);
+
+	if (!obj->funcs)
+		obj->funcs = &drm_gem_shmem_funcs;
+
+	ret = drm_gem_object_init(dev, obj, size);
+	if (ret)
+		goto err_free;
+
+	ret = drm_gem_create_mmap_offset(obj);
+	if (ret)
+		goto err_release;
+
+	shmem = to_drm_gem_shmem_obj(obj);
+	mutex_init(&shmem->pages_lock);
+	mutex_init(&shmem->vmap_lock);
+
+	return shmem;
+
+err_release:
+	drm_gem_object_release(obj);
+err_free:
+	kfree(obj);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
+
+/**
+ * drm_gem_shmem_free_object - Free resources associated with a shmem GEM object
+ * @obj: GEM object to free
+ *
+ * This function cleans up the GEM object state and frees the memory used to
+ * store the object itself.
+ */
+void drm_gem_shmem_free_object(struct drm_gem_object *obj)
+{
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	WARN_ON(shmem->vmap_use_count);
+
+	if (obj->import_attach) {
+		shmem->pages_use_count--;
+		drm_prime_gem_destroy(obj, shmem->sgt);
+		kvfree(shmem->pages);
+	}
+
+	WARN_ON(shmem->pages_use_count);
+
+	drm_gem_object_release(obj);
+	mutex_destroy(&shmem->pages_lock);
+	mutex_destroy(&shmem->vmap_lock);
+	kfree(shmem);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_free_object);
+
+static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
+{
+	struct drm_gem_object *obj = &shmem->base;
+	struct page **pages;
+
+	if (shmem->pages_use_count++ > 0)
+		return 0;
+
+	pages = drm_gem_get_pages(obj);
+	if (IS_ERR(pages)) {
+		DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages));
+		shmem->pages_use_count = 0;
+		return PTR_ERR(pages);
+	}
+
+	shmem->pages = pages;
+
+	return 0;
+}
+
+/*
+ * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
+ * @shmem: shmem GEM object
+ *
+ * This function makes sure that backing pages exists for the shmem GEM object
+ * and increases the use count.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
+{
+	int ret;
+
+	ret = mutex_lock_interruptible(&shmem->pages_lock);
+	if (ret)
+		return ret;
+	ret = drm_gem_shmem_get_pages_locked(shmem);
+	mutex_unlock(&shmem->pages_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_gem_shmem_get_pages);
+
+static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
+{
+	struct drm_gem_object *obj = &shmem->base;
+
+	if (WARN_ON_ONCE(!shmem->pages_use_count))
+		return;
+
+	if (--shmem->pages_use_count > 0)
+		return;
+
+	drm_gem_put_pages(obj, shmem->pages,
+			  shmem->pages_mark_dirty_on_put,
+			  shmem->pages_mark_accessed_on_put);
+	shmem->pages = NULL;
+}
+
+/*
+ * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
+ * @shmem: shmem GEM object
+ *
+ * This function decreases the use count and puts the backing pages when use drops to zero.
+ */
+void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
+{
+	mutex_lock(&shmem->pages_lock);
+	drm_gem_shmem_put_pages_locked(shmem);
+	mutex_unlock(&shmem->pages_lock);
+}
+EXPORT_SYMBOL(drm_gem_shmem_put_pages);
+
+/**
+ * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
+ * @obj: GEM object
+ *
+ * This function makes sure the backing pages are pinned in memory while the
+ * buffer is exported.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_pin(struct drm_gem_object *obj)
+{
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	return drm_gem_shmem_get_pages(shmem);
+}
+EXPORT_SYMBOL(drm_gem_shmem_pin);
+
+/**
+ * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
+ * @obj: GEM object
+ *
+ * This function removes the requirement that the backing pages are pinned in
+ * memory.
+ */
+void drm_gem_shmem_unpin(struct drm_gem_object *obj)
+{
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	drm_gem_shmem_put_pages(shmem);
+}
+EXPORT_SYMBOL(drm_gem_shmem_unpin);
+
+static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
+{
+	struct drm_gem_object *obj = &shmem->base;
+	int ret;
+
+	if (shmem->vmap_use_count++ > 0)
+		return shmem->vaddr;
+
+	ret = drm_gem_shmem_get_pages(shmem);
+	if (ret)
+		goto err_zero_use;
+
+	if (obj->import_attach)
+		shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf);
+	else
+		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, VM_MAP, PAGE_KERNEL);
+
+	if (!shmem->vaddr) {
+		DRM_DEBUG_KMS("Failed to vmap pages\n");
+		ret = -ENOMEM;
+		goto err_put_pages;
+	}
+
+	return shmem->vaddr;
+
+err_put_pages:
+	drm_gem_shmem_put_pages(shmem);
+err_zero_use:
+	shmem->vmap_use_count = 0;
+
+	return ERR_PTR(ret);
+}
+
+/*
+ * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
+ * @shmem: shmem GEM object
+ *
+ * This function makes sure that a virtual address exists for the buffer backing
+ * the shmem GEM object.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+void *drm_gem_shmem_vmap(struct drm_gem_object *obj)
+{
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+	void *vaddr;
+	int ret;
+
+	ret = mutex_lock_interruptible(&shmem->vmap_lock);
+	if (ret)
+		return ERR_PTR(ret);
+	vaddr = drm_gem_shmem_vmap_locked(shmem);
+	mutex_unlock(&shmem->vmap_lock);
+
+	return vaddr;
+}
+EXPORT_SYMBOL(drm_gem_shmem_vmap);
+
+static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
+{
+	struct drm_gem_object *obj = &shmem->base;
+
+	if (WARN_ON_ONCE(!shmem->vmap_use_count))
+		return;
+
+	if (--shmem->vmap_use_count > 0)
+		return;
+
+	if (obj->import_attach)
+		dma_buf_vunmap(obj->import_attach->dmabuf, shmem->vaddr);
+	else
+		vunmap(shmem->vaddr);
+
+	shmem->vaddr = NULL;
+	drm_gem_shmem_put_pages(shmem);
+}
+
+/*
+ * drm_gem_shmem_vunmap - Unmap a virtual mapping fo a shmem GEM object
+ * @shmem: shmem GEM object
+ *
+ * This function removes the virtual address when use count drops to zero.
+ */
+void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr)
+{
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	mutex_lock(&shmem->vmap_lock);
+	drm_gem_shmem_vunmap_locked(shmem);
+	mutex_unlock(&shmem->vmap_lock);
+}
+EXPORT_SYMBOL(drm_gem_shmem_vunmap);
+
+static struct drm_gem_shmem_object *
+drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
+				 struct drm_device *dev, size_t size,
+				 uint32_t *handle)
+{
+	struct drm_gem_shmem_object *shmem;
+	int ret;
+
+	shmem = drm_gem_shmem_create(dev, size);
+	if (IS_ERR(shmem))
+		return shmem;
+
+	/*
+	 * Allocate an id of idr table where the obj is registered
+	 * and handle has the id what user can see.
+	 */
+	ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
+	/* drop reference from allocate - handle holds it now. */
+	drm_gem_object_put_unlocked(&shmem->base);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return shmem;
+}
+
+/**
+ * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
+ * @file: DRM file structure to create the dumb buffer for
+ * @dev: DRM device
+ * @args: IOCTL data
+ *
+ * This function computes the pitch of the dumb buffer and rounds it up to an
+ * integer number of bytes per pixel. Drivers for hardware that doesn't have
+ * any additional restrictions on the pitch can directly use this function as
+ * their &drm_driver.dumb_create callback.
+ *
+ * For hardware with additional restrictions, drivers can adjust the fields
+ * set up by userspace before calling into this function.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
+			      struct drm_mode_create_dumb *args)
+{
+	u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+	struct drm_gem_shmem_object *shmem;
+
+	if (!args->pitch || !args->size) {
+		args->pitch = min_pitch;
+		args->size = args->pitch * args->height;
+	} else {
+		/* ensure sane minimum values */
+		if (args->pitch < min_pitch)
+			args->pitch = min_pitch;
+		if (args->size < args->pitch * args->height)
+			args->size = args->pitch * args->height;
+	}
+
+	shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
+
+	return PTR_ERR_OR_ZERO(shmem);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
+
+static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct drm_gem_object *obj = vma->vm_private_data;
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+	loff_t num_pages = obj->size >> PAGE_SHIFT;
+	struct page *page;
+
+	if (vmf->pgoff > num_pages || WARN_ON_ONCE(!shmem->pages))
+		return VM_FAULT_SIGBUS;
+
+	page = shmem->pages[vmf->pgoff];
+
+	return vmf_insert_page(vma, vmf->address, page);
+}
+
+static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
+{
+	struct drm_gem_object *obj = vma->vm_private_data;
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+	int ret;
+
+	ret = drm_gem_shmem_get_pages(shmem);
+	WARN_ON_ONCE(ret != 0);
+
+	drm_gem_vm_open(vma);
+}
+
+static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
+{
+	struct drm_gem_object *obj = vma->vm_private_data;
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	drm_gem_shmem_put_pages(shmem);
+	drm_gem_vm_close(vma);
+}
+
+const struct vm_operations_struct drm_gem_shmem_vm_ops = {
+	.fault = drm_gem_shmem_fault,
+	.open = drm_gem_shmem_vm_open,
+	.close = drm_gem_shmem_vm_close,
+};
+EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops);
+
+/**
+ * drm_gem_shmem_mmap - Memory-map a shmem GEM object
+ * @filp: File object
+ * @vma: VMA for the area to be mapped
+ *
+ * This function implements an augmented version of the GEM DRM file mmap
+ * operation for shmem objects. Drivers which employ the shmem helpers should
+ * use this function as their &file_operations.mmap handler in the DRM device file's
+ * file_operations structure.
+ *
+ * Instead of directly referencing this function, drivers should use the
+ * DEFINE_DRM_GEM_SHMEM_FOPS() macro.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct drm_gem_shmem_object *shmem;
+	int ret;
+
+	ret = drm_gem_mmap(filp, vma);
+	if (ret)
+		return ret;
+
+	shmem = to_drm_gem_shmem_obj(vma->vm_private_data);
+
+	ret = drm_gem_shmem_get_pages(shmem);
+	if (ret) {
+		drm_gem_vm_close(vma);
+		return ret;
+	}
+
+	/* VM_PFNMAP was set by drm_gem_mmap() */
+	vma->vm_flags &= ~VM_PFNMAP;
+	vma->vm_flags |= VM_MIXEDMAP;
+	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+
+	fput(vma->vm_file);
+	vma->vm_file = get_file(shmem->base.filp);
+	/* Remove the fake offset */
+	vma->vm_pgoff -= drm_vma_node_start(&shmem->base.vma_node);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
+
+/**
+ * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
+ * @p: DRM printer
+ * @indent: Tab indentation level
+ * @obj: GEM object
+ */
+void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
+			      const struct drm_gem_object *obj)
+{
+	const struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
+	drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
+	drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
+}
+EXPORT_SYMBOL(drm_gem_shmem_print_info);
+
+/**
+ * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
+ *                              pages for a shmem GEM object
+ * @obj: GEM object
+ *
+ * This function exports a scatter/gather table suitable for PRIME usage by
+ * calling the standard DMA mapping API.
+ *
+ * Returns:
+ * A pointer to the scatter/gather table of pinned pages or NULL on failure.
+ */
+struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_object *obj)
+{
+	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+	return drm_prime_pages_to_sg(shmem->pages, obj->size >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
+
+/**
+ * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
+ *                 another driver's scatter/gather table of pinned pages
+ * @dev: Device to import into
+ * @attach: DMA-BUF attachment
+ * @sgt: Scatter/gather table of pinned pages
+ *
+ * This function imports a scatter/gather table exported via DMA-BUF by
+ * another driver. Drivers that use the shmem helpers should set this as their
+ * &drm_driver.gem_prime_import_sg_table callback.
+ *
+ * Returns:
+ * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
+ * error code on failure.
+ */
+struct drm_gem_object *
+drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
+				    struct dma_buf_attachment *attach,
+				    struct sg_table *sgt)
+{
+	size_t size = PAGE_ALIGN(attach->dmabuf->size);
+	size_t npages = size >> PAGE_SHIFT;
+	struct drm_gem_shmem_object *shmem;
+	int ret;
+
+	shmem = drm_gem_shmem_create(dev, size);
+	if (IS_ERR(shmem))
+		return ERR_CAST(shmem);
+
+	shmem->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
+	if (!shmem->pages) {
+		ret = -ENOMEM;
+		goto err_free_gem;
+	}
+
+	ret = drm_prime_sg_to_page_addr_arrays(sgt, shmem->pages, NULL, npages);
+	if (ret < 0)
+		goto err_free_array;
+
+	shmem->sgt = sgt;
+	shmem->pages_use_count = 1; /* Permanently pinned from our point of view */
+
+	DRM_DEBUG_PRIME("size = %zu\n", size);
+
+	return &shmem->base;
+
+err_free_array:
+	kvfree(shmem->pages);
+err_free_gem:
+	drm_gem_object_put_unlocked(&shmem->base);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
new file mode 100644
index 000000000000..26b05e06407d
--- /dev/null
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -0,0 +1,153 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __DRM_GEM_SHMEM_HELPER_H__
+#define __DRM_GEM_SHMEM_HELPER_H__
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+
+#include <drm/drm_file.h>
+#include <drm/drm_gem.h>
+#include <drm/drm_ioctl.h>
+#include <drm/drm_prime.h>
+
+struct dma_buf_attachment;
+struct drm_mode_create_dumb;
+struct drm_printer;
+struct sg_table;
+
+/**
+ * struct drm_gem_shmem_object - GEM object backed by shmem
+ */
+struct drm_gem_shmem_object {
+	/**
+	 * @base: Base GEM object
+	 */
+	struct drm_gem_object base;
+
+	/**
+	 * @pages_lock: Protects the page table and use count
+	 */
+	struct mutex pages_lock;
+
+	/**
+	 * @pages: Page table
+	 */
+	struct page **pages;
+
+	/**
+	 * @pages_use_count:
+	 *
+	 * Reference count on the pages table.
+	 * The pages are put when the count reaches zero.
+	 */
+	unsigned int pages_use_count;
+
+	/**
+	 * @pages_mark_dirty_on_put:
+	 *
+	 * Mark pages as dirty when they are put.
+	 */
+	unsigned int pages_mark_dirty_on_put    : 1;
+
+	/**
+	 * @pages_mark_accessed_on_put:
+	 *
+	 * Mark pages as accessed when they are put.
+	 */
+	unsigned int pages_mark_accessed_on_put : 1;
+
+	/**
+	 * @sgt: Scatter/gather table for imported PRIME buffers
+	 */
+	struct sg_table *sgt;
+
+	/**
+	 * @vmap_lock: Protects the vmap address and use count
+	 */
+	struct mutex vmap_lock;
+
+	/**
+	 * @vaddr: Kernel virtual address of the backing memory
+	 */
+	void *vaddr;
+
+	/**
+	 * @vmap_use_count:
+	 *
+	 * Reference count on the virtual address.
+	 * The address are un-mapped when the count reaches zero.
+	 */
+	unsigned int vmap_use_count;
+};
+
+#define to_drm_gem_shmem_obj(obj) \
+	container_of(obj, struct drm_gem_shmem_object, base)
+
+/**
+ * DEFINE_DRM_GEM_SHMEM_FOPS() - Macro to generate file operations for shmem drivers
+ * @name: name for the generated structure
+ *
+ * This macro autogenerates a suitable &struct file_operations for shmem based
+ * drivers, which can be assigned to &drm_driver.fops. Note that this structure
+ * cannot be shared between drivers, because it contains a reference to the
+ * current module using THIS_MODULE.
+ *
+ * Note that the declaration is already marked as static - if you need a
+ * non-static version of this you're probably doing it wrong and will break the
+ * THIS_MODULE reference by accident.
+ */
+#define DEFINE_DRM_GEM_SHMEM_FOPS(name) \
+	static const struct file_operations name = {\
+		.owner		= THIS_MODULE,\
+		.open		= drm_open,\
+		.release	= drm_release,\
+		.unlocked_ioctl	= drm_ioctl,\
+		.compat_ioctl	= drm_compat_ioctl,\
+		.poll		= drm_poll,\
+		.read		= drm_read,\
+		.llseek		= noop_llseek,\
+		.mmap		= drm_gem_shmem_mmap, \
+	}
+
+struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size);
+void drm_gem_shmem_free_object(struct drm_gem_object *obj);
+
+int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem);
+void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem);
+int drm_gem_shmem_pin(struct drm_gem_object *obj);
+void drm_gem_shmem_unpin(struct drm_gem_object *obj);
+void *drm_gem_shmem_vmap(struct drm_gem_object *obj);
+void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr);
+
+int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
+			      struct drm_mode_create_dumb *args);
+
+int drm_gem_shmem_mmap(struct file *filp, struct vm_area_struct *vma);
+
+extern const struct vm_operations_struct drm_gem_shmem_vm_ops;
+
+void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
+			      const struct drm_gem_object *obj);
+
+struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_object *obj);
+struct drm_gem_object *
+drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
+				    struct dma_buf_attachment *attach,
+				    struct sg_table *sgt);
+
+/**
+ * DRM_GEM_SHMEM_DRIVER_OPS - Default shmem GEM operations
+ *
+ * This macro provides a shortcut for setting the shmem GEM operations in
+ * the &drm_driver structure.
+ */
+#define DRM_GEM_SHMEM_DRIVER_OPS \
+	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd, \
+	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle, \
+	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table, \
+	.gem_prime_mmap		= drm_gem_prime_mmap, \
+	.dumb_create		= drm_gem_shmem_dumb_create
+
+#endif /* __DRM_GEM_SHMEM_HELPER_H__ */
-- 
2.20.0.rc1

[PATCH 2/2] drm/vkms: Add PRIME support by converting to Noralf's shmem helpers.

[Eric Anholt]

This cuts out a tremendous amount of boilerplate.  I've used the PRIME
support now to test V3D rendering on a STB development board with no
KMS driver.

v2: Use the DEFINE_DRM_GEM_SHMEM_FOPS for proper mmap setup.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v1)
---
 drivers/gpu/drm/Kconfig           |   1 +
 drivers/gpu/drm/vkms/vkms_crc.c   |  28 ++--
 drivers/gpu/drm/vkms/vkms_drv.c   |  28 +---
 drivers/gpu/drm/vkms/vkms_drv.h   |  22 ----
 drivers/gpu/drm/vkms/vkms_gem.c   | 212 ++----------------------------
 drivers/gpu/drm/vkms/vkms_plane.c |  17 ++-
 6 files changed, 43 insertions(+), 265 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0dedbc040c77..3bdd95f99feb 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -253,6 +253,7 @@ config DRM_VKMS
 	tristate "Virtual KMS (EXPERIMENTAL)"
 	depends on DRM
 	select DRM_KMS_HELPER
+	select DRM_GEM_SHMEM_HELPER
 	default n
 	help
 	  Virtual Kernel Mode-Setting (VKMS) is used for testing or for
diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
index 9d9e8146db90..72d6422fb1a5 100644
--- a/drivers/gpu/drm/vkms/vkms_crc.c
+++ b/drivers/gpu/drm/vkms/vkms_crc.c
@@ -4,6 +4,7 @@
 #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>
 
 /**
  * compute_crc - Compute CRC value on output frame
@@ -91,21 +92,19 @@ static void compose_cursor(struct vkms_crc_data *cursor_crc,
 			   struct vkms_crc_data *primary_crc, void *vaddr_out)
 {
 	struct drm_gem_object *cursor_obj;
-	struct vkms_gem_object *cursor_vkms_obj;
+	void *vaddr;
 
 	cursor_obj = drm_gem_fb_get_obj(&cursor_crc->fb, 0);
-	cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
+	vaddr = drm_gem_shmem_vmap(cursor_obj);
 
-	mutex_lock(&cursor_vkms_obj->pages_lock);
-	if (!cursor_vkms_obj->vaddr) {
+	if (IS_ERR(vaddr)) {
 		DRM_WARN("cursor plane vaddr is NULL");
-		goto out;
+		return;
 	}
 
-	blend(vaddr_out, cursor_vkms_obj->vaddr, primary_crc, cursor_crc);
+	blend(vaddr_out, vaddr, primary_crc, cursor_crc);
 
-out:
-	mutex_unlock(&cursor_vkms_obj->pages_lock);
+	drm_gem_shmem_vunmap(cursor_obj, vaddr);
 }
 
 static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
@@ -113,8 +112,8 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
 {
 	struct drm_framebuffer *fb = &primary_crc->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);
-	void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
+	void *vaddr;
+	void *vaddr_out = kzalloc(gem_obj->size, GFP_KERNEL);
 	u32 crc = 0;
 
 	if (!vaddr_out) {
@@ -122,21 +121,20 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
 		return 0;
 	}
 
-	mutex_lock(&vkms_obj->pages_lock);
-	if (WARN_ON(!vkms_obj->vaddr)) {
-		mutex_unlock(&vkms_obj->pages_lock);
+	vaddr = drm_gem_shmem_vmap(gem_obj);
+	if (WARN_ON(IS_ERR(vaddr))) {
 		kfree(vaddr_out);
 		return crc;
 	}
 
-	memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
-	mutex_unlock(&vkms_obj->pages_lock);
+	memcpy(vaddr_out, vaddr, gem_obj->size);
 
 	if (cursor_crc)
 		compose_cursor(cursor_crc, primary_crc, vaddr_out);
 
 	crc = compute_crc(vaddr_out, primary_crc);
 
+	drm_gem_shmem_vunmap(gem_obj, vaddr);
 	kfree(vaddr_out);
 
 	return crc;
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 83087877565c..18f145f0f4db 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -19,6 +19,7 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_fb_helper.h>
 #include "vkms_drv.h"
 
@@ -34,23 +35,7 @@ bool enable_cursor;
 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,
-};
-
-static const struct vm_operations_struct vkms_gem_vm_ops = {
-	.fault = vkms_gem_fault,
-	.open = drm_gem_vm_open,
-	.close = drm_gem_vm_close,
-};
+DEFINE_DRM_GEM_SHMEM_FOPS(vkms_driver_fops);
 
 static void vkms_release(struct drm_device *dev)
 {
@@ -64,12 +49,13 @@ static void vkms_release(struct drm_device *dev)
 }
 
 static struct drm_driver vkms_driver = {
-	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
+	.driver_features	= (DRIVER_MODESET |
+				   DRIVER_ATOMIC |
+				   DRIVER_GEM |
+				   DRIVER_PRIME),
 	.release		= vkms_release,
 	.fops			= &vkms_driver_fops,
-	.dumb_create		= vkms_dumb_create,
-	.gem_vm_ops		= &vkms_gem_vm_ops,
-	.gem_free_object_unlocked = vkms_gem_free_object,
+	DRM_GEM_SHMEM_DRIVER_OPS,
 	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
 
 	.name			= DRIVER_NAME,
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index e4469cd3d254..3faf49f43feb 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -80,23 +80,12 @@ 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)
 
 #define drm_device_to_vkms_device(target) \
 	container_of(target, struct vkms_device, drm)
 
-#define drm_gem_to_vkms_gem(target)\
-	container_of(target, struct vkms_gem_object, gem)
-
 #define to_vkms_crtc_state(target)\
 	container_of(target, struct vkms_crtc_state, base)
 
@@ -122,17 +111,6 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
 				       u32 *handle,
 				       u64 size);
 
-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);
-
 /* CRC Support */
 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
index 80311daed47a..11f52aa4e732 100644
--- a/drivers/gpu/drm/vkms/vkms_gem.c
+++ b/drivers/gpu/drm/vkms/vkms_gem.c
@@ -7,222 +7,34 @@
  */
 
 #include <linux/shmem_fs.h>
+#include <drm/drm_gem_shmem_helper.h>
 
 #include "vkms_drv.h"
 
-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);
-
-	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;
-}
-
 struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
 				       struct drm_file *file,
 				       u32 *handle,
 				       u64 size)
 {
-	struct vkms_gem_object *obj;
+	struct drm_gem_shmem_object *obj;
 	int ret;
 
 	if (!file || !dev || !handle)
 		return ERR_PTR(-EINVAL);
 
-	obj = __vkms_gem_create(dev, size);
+	obj = drm_gem_shmem_create(dev, size);
 	if (IS_ERR(obj))
 		return ERR_CAST(obj);
 
-	ret = drm_gem_handle_create(file, &obj->gem, handle);
-	drm_gem_object_put_unlocked(&obj->gem);
-	if (ret) {
-		drm_gem_object_release(&obj->gem);
-		kfree(obj);
+	/*
+	 * Allocate an id of idr table where the obj is registered
+	 * and handle has the id what user can see.
+	 */
+	ret = drm_gem_handle_create(file, &obj->base, handle);
+	/* drop reference from allocate - handle holds it now. */
+	drm_gem_object_put_unlocked(&obj->base);
+	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_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;
+	return &obj->base;
 }
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 7041007396ae..29e6e870d7ac 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -11,6 +11,7 @@
 #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>
 
 static struct drm_plane_state *
 vkms_plane_duplicate_state(struct drm_plane *plane)
@@ -138,17 +139,17 @@ static int vkms_prepare_fb(struct drm_plane *plane,
 			   struct drm_plane_state *state)
 {
 	struct drm_gem_object *gem_obj;
-	struct vkms_gem_object *vkms_obj;
-	int ret;
+	void *map;
 
 	if (!state->fb)
 		return 0;
 
 	gem_obj = drm_gem_fb_get_obj(state->fb, 0);
-	vkms_obj = drm_gem_to_vkms_gem(gem_obj);
-	ret = vkms_gem_vmap(gem_obj);
-	if (ret)
-		DRM_ERROR("vmap failed: %d\n", ret);
+	map = drm_gem_shmem_vmap(gem_obj);
+	if (IS_ERR(map)) {
+		DRM_ERROR("vmap failed: %ld\n", PTR_ERR(map));
+		return PTR_ERR(map);
+	}
 
 	return drm_gem_fb_prepare_fb(plane, state);
 }
@@ -157,12 +158,14 @@ 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(gem_obj);
+	drm_gem_shmem_vunmap(gem_obj, shmem_obj->vaddr);
 }
 
 static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
-- 
2.20.0.rc1

Re: [PATCH 2/2] drm/vkms: Add PRIME support by converting to Noralf's shmem helpers.

[Daniel Vetter]

On Mon, Nov 26, 2018 at 01:59:29PM -0800, Eric Anholt wrote:
> This cuts out a tremendous amount of boilerplate.  I've used the PRIME
> support now to test V3D rendering on a STB development board with no
> KMS driver.
> 
> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
> 
> This patch depends on https://patchwork.freedesktop.org/series/27184/

Nice stuff. Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> on both.
> 
>  drivers/gpu/drm/Kconfig           |   1 +
>  drivers/gpu/drm/vkms/vkms_crc.c   |  28 ++--
>  drivers/gpu/drm/vkms/vkms_drv.c   |  16 +--
>  drivers/gpu/drm/vkms/vkms_drv.h   |  22 ----
>  drivers/gpu/drm/vkms/vkms_gem.c   | 212 ++----------------------------
>  drivers/gpu/drm/vkms/vkms_plane.c |  17 ++-
>  6 files changed, 42 insertions(+), 254 deletions(-)
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 0dedbc040c77..3bdd95f99feb 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -253,6 +253,7 @@ config DRM_VKMS
>  	tristate "Virtual KMS (EXPERIMENTAL)"
>  	depends on DRM
>  	select DRM_KMS_HELPER
> +	select DRM_GEM_SHMEM_HELPER
>  	default n
>  	help
>  	  Virtual Kernel Mode-Setting (VKMS) is used for testing or for
> diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
> index 9d9e8146db90..72d6422fb1a5 100644
> --- a/drivers/gpu/drm/vkms/vkms_crc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crc.c
> @@ -4,6 +4,7 @@
>  #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>
>  
>  /**
>   * compute_crc - Compute CRC value on output frame
> @@ -91,21 +92,19 @@ static void compose_cursor(struct vkms_crc_data *cursor_crc,
>  			   struct vkms_crc_data *primary_crc, void *vaddr_out)
>  {
>  	struct drm_gem_object *cursor_obj;
> -	struct vkms_gem_object *cursor_vkms_obj;
> +	void *vaddr;
>  
>  	cursor_obj = drm_gem_fb_get_obj(&cursor_crc->fb, 0);
> -	cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
> +	vaddr = drm_gem_shmem_vmap(cursor_obj);
>  
> -	mutex_lock(&cursor_vkms_obj->pages_lock);
> -	if (!cursor_vkms_obj->vaddr) {
> +	if (IS_ERR(vaddr)) {
>  		DRM_WARN("cursor plane vaddr is NULL");
> -		goto out;
> +		return;
>  	}
>  
> -	blend(vaddr_out, cursor_vkms_obj->vaddr, primary_crc, cursor_crc);
> +	blend(vaddr_out, vaddr, primary_crc, cursor_crc);
>  
> -out:
> -	mutex_unlock(&cursor_vkms_obj->pages_lock);
> +	drm_gem_shmem_vunmap(cursor_obj, vaddr);
>  }
>  
>  static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
> @@ -113,8 +112,8 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
>  {
>  	struct drm_framebuffer *fb = &primary_crc->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);
> -	void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
> +	void *vaddr;
> +	void *vaddr_out = kzalloc(gem_obj->size, GFP_KERNEL);
>  	u32 crc = 0;
>  
>  	if (!vaddr_out) {
> @@ -122,21 +121,20 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
>  		return 0;
>  	}
>  
> -	mutex_lock(&vkms_obj->pages_lock);
> -	if (WARN_ON(!vkms_obj->vaddr)) {
> -		mutex_unlock(&vkms_obj->pages_lock);
> +	vaddr = drm_gem_shmem_vmap(gem_obj);
> +	if (WARN_ON(IS_ERR(vaddr))) {
>  		kfree(vaddr_out);
>  		return crc;
>  	}
>  
> -	memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
> -	mutex_unlock(&vkms_obj->pages_lock);
> +	memcpy(vaddr_out, vaddr, gem_obj->size);
>  
>  	if (cursor_crc)
>  		compose_cursor(cursor_crc, primary_crc, vaddr_out);
>  
>  	crc = compute_crc(vaddr_out, primary_crc);
>  
> +	drm_gem_shmem_vunmap(gem_obj, vaddr);
>  	kfree(vaddr_out);
>  
>  	return crc;
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index 83087877565c..fa26e2675028 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -19,6 +19,7 @@
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
>  #include <drm/drm_fb_helper.h>
>  #include "vkms_drv.h"
>  
> @@ -46,12 +47,6 @@ static const struct file_operations vkms_driver_fops = {
>  	.release	= drm_release,
>  };
>  
> -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 void vkms_release(struct drm_device *dev)
>  {
>  	struct vkms_device *vkms = container_of(dev, struct vkms_device, drm);
> @@ -64,12 +59,13 @@ static void vkms_release(struct drm_device *dev)
>  }
>  
>  static struct drm_driver vkms_driver = {
> -	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
> +	.driver_features	= (DRIVER_MODESET |
> +				   DRIVER_ATOMIC |
> +				   DRIVER_GEM |
> +				   DRIVER_PRIME),
>  	.release		= vkms_release,
>  	.fops			= &vkms_driver_fops,
> -	.dumb_create		= vkms_dumb_create,
> -	.gem_vm_ops		= &vkms_gem_vm_ops,
> -	.gem_free_object_unlocked = vkms_gem_free_object,
> +	DRM_GEM_SHMEM_DRIVER_OPS,
>  	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
>  
>  	.name			= DRIVER_NAME,
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index e4469cd3d254..3faf49f43feb 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -80,23 +80,12 @@ 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)
>  
>  #define drm_device_to_vkms_device(target) \
>  	container_of(target, struct vkms_device, drm)
>  
> -#define drm_gem_to_vkms_gem(target)\
> -	container_of(target, struct vkms_gem_object, gem)
> -
>  #define to_vkms_crtc_state(target)\
>  	container_of(target, struct vkms_crtc_state, base)
>  
> @@ -122,17 +111,6 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
>  				       u32 *handle,
>  				       u64 size);
>  
> -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);
> -
>  /* CRC Support */
>  int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name);
>  int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
> diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
> index 80311daed47a..11f52aa4e732 100644
> --- a/drivers/gpu/drm/vkms/vkms_gem.c
> +++ b/drivers/gpu/drm/vkms/vkms_gem.c
> @@ -7,222 +7,34 @@
>   */
>  
>  #include <linux/shmem_fs.h>
> +#include <drm/drm_gem_shmem_helper.h>
>  
>  #include "vkms_drv.h"
>  
> -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);
> -
> -	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;
> -}
> -
>  struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
>  				       struct drm_file *file,
>  				       u32 *handle,
>  				       u64 size)
>  {
> -	struct vkms_gem_object *obj;
> +	struct drm_gem_shmem_object *obj;
>  	int ret;
>  
>  	if (!file || !dev || !handle)
>  		return ERR_PTR(-EINVAL);
>  
> -	obj = __vkms_gem_create(dev, size);
> +	obj = drm_gem_shmem_create(dev, size);
>  	if (IS_ERR(obj))
>  		return ERR_CAST(obj);
>  
> -	ret = drm_gem_handle_create(file, &obj->gem, handle);
> -	drm_gem_object_put_unlocked(&obj->gem);
> -	if (ret) {
> -		drm_gem_object_release(&obj->gem);
> -		kfree(obj);
> +	/*
> +	 * Allocate an id of idr table where the obj is registered
> +	 * and handle has the id what user can see.
> +	 */
> +	ret = drm_gem_handle_create(file, &obj->base, handle);
> +	/* drop reference from allocate - handle holds it now. */
> +	drm_gem_object_put_unlocked(&obj->base);
> +	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_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;
> +	return &obj->base;
>  }
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> index 7041007396ae..29e6e870d7ac 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.c
> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> @@ -11,6 +11,7 @@
>  #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>
>  
>  static struct drm_plane_state *
>  vkms_plane_duplicate_state(struct drm_plane *plane)
> @@ -138,17 +139,17 @@ static int vkms_prepare_fb(struct drm_plane *plane,
>  			   struct drm_plane_state *state)
>  {
>  	struct drm_gem_object *gem_obj;
> -	struct vkms_gem_object *vkms_obj;
> -	int ret;
> +	void *map;
>  
>  	if (!state->fb)
>  		return 0;
>  
>  	gem_obj = drm_gem_fb_get_obj(state->fb, 0);
> -	vkms_obj = drm_gem_to_vkms_gem(gem_obj);
> -	ret = vkms_gem_vmap(gem_obj);
> -	if (ret)
> -		DRM_ERROR("vmap failed: %d\n", ret);
> +	map = drm_gem_shmem_vmap(gem_obj);
> +	if (IS_ERR(map)) {
> +		DRM_ERROR("vmap failed: %ld\n", PTR_ERR(map));
> +		return PTR_ERR(map);
> +	}
>  
>  	return drm_gem_fb_prepare_fb(plane, state);
>  }
> @@ -157,12 +158,14 @@ 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(gem_obj);
> +	drm_gem_shmem_vunmap(gem_obj, shmem_obj->vaddr);
>  }
>  
>  static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
> -- 
> 2.20.0.rc1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH 2/2] drm/vkms: Add PRIME support by converting to Noralf's shmem helpers.

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1790 bytes --]

Hi Eric,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.20-rc4 next-20181126]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Eric-Anholt/drm-vkms-Drop-custom-vkms_dumb_map/20181127-072142
config: i386-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/vkms/vkms_drv.c:22:10: fatal error: drm/drm_gem_shmem_helper.h: No such file or directory
    #include <drm/drm_gem_shmem_helper.h>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   compilation terminated.
--
>> drivers/gpu/drm/vkms/vkms_plane.c:14:10: fatal error: drm/drm_gem_shmem_helper.h: No such file or directory
    #include <drm/drm_gem_shmem_helper.h>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   compilation terminated.
--
>> drivers/gpu/drm/vkms/vkms_gem.c:10:10: fatal error: drm/drm_gem_shmem_helper.h: No such file or directory
    #include <drm/drm_gem_shmem_helper.h>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   compilation terminated.
--
>> drivers/gpu/drm/vkms/vkms_crc.c:7:10: fatal error: drm/drm_gem_shmem_helper.h: No such file or directory
    #include <drm/drm_gem_shmem_helper.h>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   compilation terminated.

vim +22 drivers/gpu/drm/vkms/vkms_drv.c

  > 22	#include <drm/drm_gem_shmem_helper.h>
    23	#include <drm/drm_fb_helper.h>
    24	#include "vkms_drv.h"
    25	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 66023 bytes --]

[PATCH 2/2] drm/vkms: Add PRIME support by converting to Noralf's shmem helpers.

[Eric Anholt]

This cuts out a tremendous amount of boilerplate.  I've used the PRIME
support now to test V3D rendering on a STB development board with no
KMS driver.

Signed-off-by: Eric Anholt <eric@anholt.net>
---

This patch depends on https://patchwork.freedesktop.org/series/27184/

 drivers/gpu/drm/Kconfig           |   1 +
 drivers/gpu/drm/vkms/vkms_crc.c   |  28 ++--
 drivers/gpu/drm/vkms/vkms_drv.c   |  16 +--
 drivers/gpu/drm/vkms/vkms_drv.h   |  22 ----
 drivers/gpu/drm/vkms/vkms_gem.c   | 212 ++----------------------------
 drivers/gpu/drm/vkms/vkms_plane.c |  17 ++-
 6 files changed, 42 insertions(+), 254 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0dedbc040c77..3bdd95f99feb 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -253,6 +253,7 @@ config DRM_VKMS
 	tristate "Virtual KMS (EXPERIMENTAL)"
 	depends on DRM
 	select DRM_KMS_HELPER
+	select DRM_GEM_SHMEM_HELPER
 	default n
 	help
 	  Virtual Kernel Mode-Setting (VKMS) is used for testing or for
diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
index 9d9e8146db90..72d6422fb1a5 100644
--- a/drivers/gpu/drm/vkms/vkms_crc.c
+++ b/drivers/gpu/drm/vkms/vkms_crc.c
@@ -4,6 +4,7 @@
 #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>
 
 /**
  * compute_crc - Compute CRC value on output frame
@@ -91,21 +92,19 @@ static void compose_cursor(struct vkms_crc_data *cursor_crc,
 			   struct vkms_crc_data *primary_crc, void *vaddr_out)
 {
 	struct drm_gem_object *cursor_obj;
-	struct vkms_gem_object *cursor_vkms_obj;
+	void *vaddr;
 
 	cursor_obj = drm_gem_fb_get_obj(&cursor_crc->fb, 0);
-	cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
+	vaddr = drm_gem_shmem_vmap(cursor_obj);
 
-	mutex_lock(&cursor_vkms_obj->pages_lock);
-	if (!cursor_vkms_obj->vaddr) {
+	if (IS_ERR(vaddr)) {
 		DRM_WARN("cursor plane vaddr is NULL");
-		goto out;
+		return;
 	}
 
-	blend(vaddr_out, cursor_vkms_obj->vaddr, primary_crc, cursor_crc);
+	blend(vaddr_out, vaddr, primary_crc, cursor_crc);
 
-out:
-	mutex_unlock(&cursor_vkms_obj->pages_lock);
+	drm_gem_shmem_vunmap(cursor_obj, vaddr);
 }
 
 static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
@@ -113,8 +112,8 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
 {
 	struct drm_framebuffer *fb = &primary_crc->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);
-	void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
+	void *vaddr;
+	void *vaddr_out = kzalloc(gem_obj->size, GFP_KERNEL);
 	u32 crc = 0;
 
 	if (!vaddr_out) {
@@ -122,21 +121,20 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
 		return 0;
 	}
 
-	mutex_lock(&vkms_obj->pages_lock);
-	if (WARN_ON(!vkms_obj->vaddr)) {
-		mutex_unlock(&vkms_obj->pages_lock);
+	vaddr = drm_gem_shmem_vmap(gem_obj);
+	if (WARN_ON(IS_ERR(vaddr))) {
 		kfree(vaddr_out);
 		return crc;
 	}
 
-	memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
-	mutex_unlock(&vkms_obj->pages_lock);
+	memcpy(vaddr_out, vaddr, gem_obj->size);
 
 	if (cursor_crc)
 		compose_cursor(cursor_crc, primary_crc, vaddr_out);
 
 	crc = compute_crc(vaddr_out, primary_crc);
 
+	drm_gem_shmem_vunmap(gem_obj, vaddr);
 	kfree(vaddr_out);
 
 	return crc;
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 83087877565c..fa26e2675028 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -19,6 +19,7 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_fb_helper.h>
 #include "vkms_drv.h"
 
@@ -46,12 +47,6 @@ static const struct file_operations vkms_driver_fops = {
 	.release	= drm_release,
 };
 
-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 void vkms_release(struct drm_device *dev)
 {
 	struct vkms_device *vkms = container_of(dev, struct vkms_device, drm);
@@ -64,12 +59,13 @@ static void vkms_release(struct drm_device *dev)
 }
 
 static struct drm_driver vkms_driver = {
-	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
+	.driver_features	= (DRIVER_MODESET |
+				   DRIVER_ATOMIC |
+				   DRIVER_GEM |
+				   DRIVER_PRIME),
 	.release		= vkms_release,
 	.fops			= &vkms_driver_fops,
-	.dumb_create		= vkms_dumb_create,
-	.gem_vm_ops		= &vkms_gem_vm_ops,
-	.gem_free_object_unlocked = vkms_gem_free_object,
+	DRM_GEM_SHMEM_DRIVER_OPS,
 	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
 
 	.name			= DRIVER_NAME,
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index e4469cd3d254..3faf49f43feb 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -80,23 +80,12 @@ 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)
 
 #define drm_device_to_vkms_device(target) \
 	container_of(target, struct vkms_device, drm)
 
-#define drm_gem_to_vkms_gem(target)\
-	container_of(target, struct vkms_gem_object, gem)
-
 #define to_vkms_crtc_state(target)\
 	container_of(target, struct vkms_crtc_state, base)
 
@@ -122,17 +111,6 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
 				       u32 *handle,
 				       u64 size);
 
-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);
-
 /* CRC Support */
 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
index 80311daed47a..11f52aa4e732 100644
--- a/drivers/gpu/drm/vkms/vkms_gem.c
+++ b/drivers/gpu/drm/vkms/vkms_gem.c
@@ -7,222 +7,34 @@
  */
 
 #include <linux/shmem_fs.h>
+#include <drm/drm_gem_shmem_helper.h>
 
 #include "vkms_drv.h"
 
-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);
-
-	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;
-}
-
 struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
 				       struct drm_file *file,
 				       u32 *handle,
 				       u64 size)
 {
-	struct vkms_gem_object *obj;
+	struct drm_gem_shmem_object *obj;
 	int ret;
 
 	if (!file || !dev || !handle)
 		return ERR_PTR(-EINVAL);
 
-	obj = __vkms_gem_create(dev, size);
+	obj = drm_gem_shmem_create(dev, size);
 	if (IS_ERR(obj))
 		return ERR_CAST(obj);
 
-	ret = drm_gem_handle_create(file, &obj->gem, handle);
-	drm_gem_object_put_unlocked(&obj->gem);
-	if (ret) {
-		drm_gem_object_release(&obj->gem);
-		kfree(obj);
+	/*
+	 * Allocate an id of idr table where the obj is registered
+	 * and handle has the id what user can see.
+	 */
+	ret = drm_gem_handle_create(file, &obj->base, handle);
+	/* drop reference from allocate - handle holds it now. */
+	drm_gem_object_put_unlocked(&obj->base);
+	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_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;
+	return &obj->base;
 }
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 7041007396ae..29e6e870d7ac 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -11,6 +11,7 @@
 #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>
 
 static struct drm_plane_state *
 vkms_plane_duplicate_state(struct drm_plane *plane)
@@ -138,17 +139,17 @@ static int vkms_prepare_fb(struct drm_plane *plane,
 			   struct drm_plane_state *state)
 {
 	struct drm_gem_object *gem_obj;
-	struct vkms_gem_object *vkms_obj;
-	int ret;
+	void *map;
 
 	if (!state->fb)
 		return 0;
 
 	gem_obj = drm_gem_fb_get_obj(state->fb, 0);
-	vkms_obj = drm_gem_to_vkms_gem(gem_obj);
-	ret = vkms_gem_vmap(gem_obj);
-	if (ret)
-		DRM_ERROR("vmap failed: %d\n", ret);
+	map = drm_gem_shmem_vmap(gem_obj);
+	if (IS_ERR(map)) {
+		DRM_ERROR("vmap failed: %ld\n", PTR_ERR(map));
+		return PTR_ERR(map);
+	}
 
 	return drm_gem_fb_prepare_fb(plane, state);
 }
@@ -157,12 +158,14 @@ 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(gem_obj);
+	drm_gem_shmem_vunmap(gem_obj, shmem_obj->vaddr);
 }
 
 static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
-- 
2.20.0.rc1