On Thu, Jan 21, 2021 at 05:09:14PM +0800, Zhou Wang wrote:
> When IO page fault happens, DMA performance will be affected. Pin user page
> can avoid IO page fault, this patch introduces a new char device named
> /dev/uacce_ctrl to help to maintain pin/unpin pages. User space can do
> pin/unpin pages by ioctls of an open file of /dev/uacce_ctrl, all pinned
> pages under one file will be unpinned in file release process.
>
> Signed-off-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
> Signed-off-by: Sihang Chen <chensihang1@xxxxxxxxxxxxx>
> Suggested-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
> ---
> drivers/misc/uacce/uacce.c | 172 +++++++++++++++++++++++++++++++++++++++-
> include/uapi/misc/uacce/uacce.h | 16 ++++
> 2 files changed, 187 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
> index d07af4e..b8ac408 100644
> --- a/drivers/misc/uacce/uacce.c
> +++ b/drivers/misc/uacce/uacce.c
> @@ -2,6 +2,7 @@
> #include <linux/compat.h>
> #include <linux/dma-mapping.h>
> #include <linux/iommu.h>
> +#include <linux/miscdevice.h>
> #include <linux/module.h>
> #include <linux/poll.h>
> #include <linux/slab.h>
> @@ -12,6 +13,16 @@ static dev_t uacce_devt;
> static DEFINE_MUTEX(uacce_mutex);
> static DEFINE_XARRAY_ALLOC(uacce_xa);
>
> +struct uacce_pin_container {
> + struct xarray array;
> +};
> +
> +struct pin_pages {
> + unsigned long first;
> + unsigned long nr_pages;
> + struct page **pages;
> +};
> +
> static int uacce_start_queue(struct uacce_queue *q)
> {
> int ret = 0;
> @@ -497,6 +508,152 @@ void uacce_remove(struct uacce_device *uacce)
> }
> EXPORT_SYMBOL_GPL(uacce_remove);
>
> +int uacce_ctrl_open(struct inode *inode, struct file *file)
> +{
> + struct uacce_pin_container *p;
> +
> + p = kzalloc(sizeof(*p), GFP_KERNEL);
> + if (!p)
> + return -ENOMEM;
> + file->private_data = p;
> +
> + xa_init(&p->array);
> +
> + return 0;
> +}
> +
> +int uacce_ctrl_release(struct inode *inode, struct file *file)
> +{
> + struct uacce_pin_container *priv = file->private_data;
> + struct pin_pages *p;
> + unsigned long idx;
> +
> + xa_for_each(&priv->array, idx, p) {
> + unpin_user_pages(p->pages, p->nr_pages);
> + xa_erase(&priv->array, p->first);
> + vfree(p->pages);
> + kfree(p);
> + }
> +
> + xa_destroy(&priv->array);
> + kfree(priv);
> +
> + return 0;
> +}
> +
> +static int uacce_pin_page(struct uacce_pin_container *priv,
> + struct uacce_pin_address *addr)
> +{
> + unsigned int flags = FOLL_FORCE | FOLL_WRITE;
> + unsigned long first, last, nr_pages;
> + struct page **pages;
> + struct pin_pages *p;
> + int ret;
> +
> + first = (addr->addr & PAGE_MASK) >> PAGE_SHIFT;
> + last = ((addr->addr + addr->size - 1) & PAGE_MASK) >> PAGE_SHIFT;
> + nr_pages = last - first + 1;
> +
> + pages = vmalloc(nr_pages * sizeof(struct page *));
> + if (!pages)
> + return -ENOMEM;
> +
> + p = kzalloc(sizeof(*p), GFP_KERNEL);
> + if (!p) {
> + ret = -ENOMEM;
> + goto free;
> + }
> +
> + ret = pin_user_pages_fast(addr->addr & PAGE_MASK, nr_pages,
> + flags | FOLL_LONGTERM, pages);
> + if (ret != nr_pages) {
> + pr_err("uacce: Failed to pin page\n");
> + goto free_p;
> + }
> + p->first = first;
> + p->nr_pages = nr_pages;
> + p->pages = pages;
> +
> + ret = xa_err(xa_store(&priv->array, p->first, p, GFP_KERNEL));
> + if (ret)
> + goto unpin_pages;
> +
> + return 0;
> +
> +unpin_pages:
> + unpin_user_pages(pages, nr_pages);
> +free_p:
> + kfree(p);
> +free:
> + vfree(pages);
> + return ret;
> +}
> +
> +static int uacce_unpin_page(struct uacce_pin_container *priv,
> + struct uacce_pin_address *addr)
> +{
> + unsigned long first, last, nr_pages;
> + struct pin_pages *p;
> +
> + first = (addr->addr & PAGE_MASK) >> PAGE_SHIFT;
> + last = ((addr->addr + addr->size - 1) & PAGE_MASK) >> PAGE_SHIFT;
> + nr_pages = last - first + 1;
> +
> + /* find pin_pages */
> + p = xa_load(&priv->array, first);
> + if (!p)
> + return -ENODEV;
> +
> + if (p->nr_pages != nr_pages)
> + return -EINVAL;
> +
> + /* unpin */
> + unpin_user_pages(p->pages, p->nr_pages);
> +
> + /* release resource */
> + xa_erase(&priv->array, first);
> + vfree(p->pages);
> + kfree(p);
> +
> + return 0;
> +}
> +
> +static long uacce_ctrl_unl_ioctl(struct file *filep, unsigned int cmd,
> + unsigned long arg)
> +{
> + struct uacce_pin_container *p = filep->private_data;
> + struct uacce_pin_address addr;
> + int ret;
> +
> + if (copy_from_user(&addr, (void __user *)arg,
> + sizeof(struct uacce_pin_address)))
> + return -EFAULT;
> +
> + switch (cmd) {
> + case UACCE_CMD_PIN:
> + return uacce_pin_page(p, &addr);
> +
> + case UACCE_CMD_UNPIN:
> + return uacce_unpin_page(p, &addr);
> +
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct file_operations uacce_ctrl_fops = {
> + .owner = THIS_MODULE,
> + .open = uacce_ctrl_open,
> + .release = uacce_ctrl_release,
> + .unlocked_ioctl = uacce_ctrl_unl_ioctl,
> +};
> +
> +static struct miscdevice uacce_ctrl_miscdev = {
> + .name = "uacce_ctrl",
> + .minor = MISC_DYNAMIC_MINOR,
> + .fops = &uacce_ctrl_fops,
> +};
> +
> static int __init uacce_init(void)
> {
> int ret;
> @@ -507,13 +664,26 @@ static int __init uacce_init(void)
>
> ret = alloc_chrdev_region(&uacce_devt, 0, MINORMASK, UACCE_NAME);
> if (ret)
> - class_destroy(uacce_class);
> + goto destroy_class;
> +
> + ret = misc_register(&uacce_ctrl_miscdev);
> + if (ret) {
> + pr_err("uacce: ctrl dev registration failed\n");
> + goto unregister_cdev;
> + }
>
> + return 0;
> +
> +unregister_cdev:
> + unregister_chrdev_region(uacce_devt, MINORMASK);
> +destroy_class:
> + class_destroy(uacce_class);
> return ret;
> }
>
> static __exit void uacce_exit(void)
> {
> + misc_deregister(&uacce_ctrl_miscdev);
> unregister_chrdev_region(uacce_devt, MINORMASK);
> class_destroy(uacce_class);
> }
> diff --git a/include/uapi/misc/uacce/uacce.h b/include/uapi/misc/uacce/uacce.h
> index cc71856..f9e326f 100644
> --- a/include/uapi/misc/uacce/uacce.h
> +++ b/include/uapi/misc/uacce/uacce.h
> @@ -35,4 +35,20 @@ enum uacce_qfrt {
> UACCE_QFRT_DUS = 1,
> };
>
> +/**
> + * struct uacce_pin_address - Expected pin user space address and size
> + * @addr: Address to pin
> + * @size: Size of pin address
> + */
> +struct uacce_pin_address {
> + unsigned long addr;
> + unsigned long size;
These are not valid ioctl structure members for crossing the user/kernel
boundry. Please make them work properly (i.e. use __u64 and friends).
thanks,
greg k-h
