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/*
* videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-memops.h>
struct vb2_vmalloc_buf {
void *vaddr;
struct page **pages;
int write;
unsigned long size;
unsigned int n_pages;
atomic_t refcount;
struct vb2_vmarea_handler handler;
};
static void vb2_vmalloc_put(void *buf_priv);
static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
{
struct vb2_vmalloc_buf *buf;
buf = kzalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
return NULL;
buf->size = size;
buf->vaddr = vmalloc_user(buf->size);
buf->handler.refcount = &buf->refcount;
buf->handler.put = vb2_vmalloc_put;
buf->handler.arg = buf;
if (!buf->vaddr) {
pr_debug("vmalloc of size %ld failed\n", buf->size);
kfree(buf);
return NULL;
}
atomic_inc(&buf->refcount);
return buf;
}
static void vb2_vmalloc_put(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
if (atomic_dec_and_test(&buf->refcount)) {
vfree(buf->vaddr);
kfree(buf);
}
}
static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write)
{
struct vb2_vmalloc_buf *buf;
unsigned long first, last;
int n_pages, offset;
buf = kzalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
return NULL;
buf->write = write;
offset = vaddr & ~PAGE_MASK;
buf->size = size;
first = vaddr >> PAGE_SHIFT;
last = (vaddr + size - 1) >> PAGE_SHIFT;
buf->n_pages = last - first + 1;
buf->pages = kzalloc(buf->n_pages * sizeof(struct page *), GFP_KERNEL);
if (!buf->pages)
goto fail_pages_array_alloc;
/* current->mm->mmap_sem is taken by videobuf2 core */
n_pages = get_user_pages(current, current->mm, vaddr & PAGE_MASK,
buf->n_pages, write, 1, /* force */
buf->pages, NULL);
if (n_pages != buf->n_pages)
goto fail_get_user_pages;
buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1, PAGE_KERNEL);
if (!buf->vaddr)
goto fail_get_user_pages;
buf->vaddr += offset;
return buf;
fail_get_user_pages:
pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
buf->n_pages);
while (--n_pages >= 0)
put_page(buf->pages[n_pages]);
kfree(buf->pages);
fail_pages_array_alloc:
kfree(buf);
return NULL;
}
static void vb2_vmalloc_put_userptr(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
unsigned int i;
if (vaddr)
vm_unmap_ram((void *)vaddr, buf->n_pages);
for (i = 0; i < buf->n_pages; ++i) {
if (buf->write)
set_page_dirty_lock(buf->pages[i]);
put_page(buf->pages[i]);
}
kfree(buf->pages);
kfree(buf);
}
static void *vb2_vmalloc_vaddr(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
if (!buf->vaddr) {
pr_err("Address of an unallocated plane requested "
"or cannot map user pointer\n");
return NULL;
}
return buf->vaddr;
}
static unsigned int vb2_vmalloc_num_users(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
return atomic_read(&buf->refcount);
}
static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
{
struct vb2_vmalloc_buf *buf = buf_priv;
int ret;
if (!buf) {
pr_err("No memory to map\n");
return -EINVAL;
}
ret = remap_vmalloc_range(vma, buf->vaddr, 0);
if (ret) {
pr_err("Remapping vmalloc memory, error: %d\n", ret);
return ret;
}
/*
* Make sure that vm_areas for 2 buffers won't be merged together
*/
vma->vm_flags |= VM_DONTEXPAND;
/*
* Use common vm_area operations to track buffer refcount.
*/
vma->vm_private_data = &buf->handler;
vma->vm_ops = &vb2_common_vm_ops;
vma->vm_ops->open(vma);
return 0;
}
const struct vb2_mem_ops vb2_vmalloc_memops = {
.alloc = vb2_vmalloc_alloc,
.put = vb2_vmalloc_put,
.get_userptr = vb2_vmalloc_get_userptr,
.put_userptr = vb2_vmalloc_put_userptr,
.vaddr = vb2_vmalloc_vaddr,
.mmap = vb2_vmalloc_mmap,
.num_users = vb2_vmalloc_num_users,
};
EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
MODULE_LICENSE("GPL");
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