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// SPDX-License-Identifier: GPL-2.0+
#include <linux/shmem_fs.h>
#include <linux/vmalloc.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;
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);
drm_gem_object_put_unlocked(&obj->gem);
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;
}
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