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// SPDX-License-Identifier: MIT
/*
* Copyright © 2020 Intel Corporation
*/
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/shmem_fs.h>
#include "gem/i915_gem_object.h"
#include "shmem_utils.h"
struct file *shmem_create_from_data(const char *name, void *data, size_t len)
{
struct file *file;
int err;
file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
if (IS_ERR(file))
return file;
err = shmem_write(file, 0, data, len);
if (err) {
fput(file);
return ERR_PTR(err);
}
return file;
}
struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
{
struct file *file;
void *ptr;
if (obj->ops == &i915_gem_shmem_ops) {
file = obj->base.filp;
atomic_long_inc(&file->f_count);
return file;
}
ptr = i915_gem_object_pin_map(obj, I915_MAP_WB);
if (IS_ERR(ptr))
return ERR_CAST(ptr);
file = shmem_create_from_data("", ptr, obj->base.size);
i915_gem_object_unpin_map(obj);
return file;
}
static size_t shmem_npte(struct file *file)
{
return file->f_mapping->host->i_size >> PAGE_SHIFT;
}
static void __shmem_unpin_map(struct file *file, void *ptr, size_t n_pte)
{
unsigned long pfn;
vunmap(ptr);
for (pfn = 0; pfn < n_pte; pfn++) {
struct page *page;
page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
GFP_KERNEL);
if (!WARN_ON(IS_ERR(page))) {
put_page(page);
put_page(page);
}
}
}
void *shmem_pin_map(struct file *file)
{
const size_t n_pte = shmem_npte(file);
pte_t *stack[32], **ptes, **mem;
struct vm_struct *area;
unsigned long pfn;
mem = stack;
if (n_pte > ARRAY_SIZE(stack)) {
mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
if (!mem)
return NULL;
}
area = alloc_vm_area(n_pte << PAGE_SHIFT, mem);
if (!area) {
if (mem != stack)
kvfree(mem);
return NULL;
}
ptes = mem;
for (pfn = 0; pfn < n_pte; pfn++) {
struct page *page;
page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
GFP_KERNEL);
if (IS_ERR(page))
goto err_page;
**ptes++ = mk_pte(page, PAGE_KERNEL);
}
if (mem != stack)
kvfree(mem);
mapping_set_unevictable(file->f_mapping);
return area->addr;
err_page:
if (mem != stack)
kvfree(mem);
__shmem_unpin_map(file, area->addr, pfn);
return NULL;
}
void shmem_unpin_map(struct file *file, void *ptr)
{
mapping_clear_unevictable(file->f_mapping);
__shmem_unpin_map(file, ptr, shmem_npte(file));
}
static int __shmem_rw(struct file *file, loff_t off,
void *ptr, size_t len,
bool write)
{
unsigned long pfn;
for (pfn = off >> PAGE_SHIFT; len; pfn++) {
unsigned int this =
min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
struct page *page;
void *vaddr;
page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
GFP_KERNEL);
if (IS_ERR(page))
return PTR_ERR(page);
vaddr = kmap(page);
if (write)
memcpy(vaddr + offset_in_page(off), ptr, this);
else
memcpy(ptr, vaddr + offset_in_page(off), this);
kunmap(page);
put_page(page);
len -= this;
ptr += this;
off = 0;
}
return 0;
}
int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
{
return __shmem_rw(file, off, dst, len, false);
}
int shmem_write(struct file *file, loff_t off, void *src, size_t len)
{
return __shmem_rw(file, off, src, len, true);
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "st_shmem_utils.c"
#endif
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