[Intel-gfx] [PATCH v2 4/4] drm/vgem: use shmem helpers
Daniel Vetter
daniel.vetter at ffwll.ch
Thu Jun 3 15:03:26 UTC 2021
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)
v4: I got tricked by 0cf2ef46c6c0 ("drm/shmem-helper: Use cached
mappings by default"), and we need WC in vgem because vgem doesn't
have explicit begin/end cpu access ioctls.
Also add a comment why exactly vgem has to use wc.
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 | 346 ++------------------------------
2 files changed, 17 insertions(+), 330 deletions(-)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 9c21527b791f..fb38ef7b3206 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -268,6 +268,7 @@ 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 bf38a7e319d1..031e8f026cfb 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;
@@ -159,266 +84,32 @@ 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);
+DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
- 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)
+/*
+ * This just sets wc mode for shmem helpers. vgem doesn't have any begin/end cpu
+ * access ioctls, there must use coherent memory or dma-buf sharing just wont
+ * work.
+ */
+static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, size_t size)
{
- struct drm_vgem_gem_object *obj;
- int npages;
+ struct drm_gem_shmem_object *obj;
- 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 = kzalloc(sizeof(*obj), GFP_KERNEL);
+ if (!obj)
+ return NULL;
- 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->base.funcs = &drm_gem_shmem_funcs;
+ obj->map_wc = true;
- 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,
-};
-
static const struct drm_driver vgem_driver = {
.driver_features = DRIVER_GEM | DRIVER_RENDER,
.open = vgem_open,
@@ -427,13 +118,8 @@ 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,
+ .gem_create_object = vgem_gem_create_object,
.name = DRIVER_NAME,
.desc = DRIVER_DESC,
--
2.31.0
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