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SubjectRe: [PATCH 8/8] xen/gntdev: Expose gntdev's dma-buf API for in-kernel use
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On 05/25/2018 06:33 PM, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
>
> Allow creating grant device context for use by kernel modules which
> require functionality, provided by gntdev. Export symbols for dma-buf
> API provided by the module.
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
> ---
> drivers/xen/gntdev.c | 116 ++++++++++++++++++++++++++--------------
> include/xen/grant_dev.h | 37 +++++++++++++
> 2 files changed, 113 insertions(+), 40 deletions(-)
> create mode 100644 include/xen/grant_dev.h
>
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index d8b6168f2cd9..912056f3e909 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -684,14 +684,33 @@ static const struct mmu_notifier_ops gntdev_mmu_ops = {
>
> /* ------------------------------------------------------------------ */
>
> -static int gntdev_open(struct inode *inode, struct file *flip)
> +void gntdev_free_context(struct gntdev_priv *priv)
> +{
> + struct grant_map *map;
> +
> + pr_debug("priv %p\n", priv);
> +
> + mutex_lock(&priv->lock);
> + while (!list_empty(&priv->maps)) {
> + map = list_entry(priv->maps.next, struct grant_map, next);
> + list_del(&map->next);
> + gntdev_put_map(NULL /* already removed */, map);
> + }
> + WARN_ON(!list_empty(&priv->freeable_maps));
> +
> + mutex_unlock(&priv->lock);
> +
> + kfree(priv);
> +}
> +EXPORT_SYMBOL(gntdev_free_context);
I will convert EXPORT_SYMBOL to EXPORT_SYMBOL_GPL here and below
> +
> +struct gntdev_priv *gntdev_alloc_context(struct device *dev)
> {
> struct gntdev_priv *priv;
> - int ret = 0;
>
> priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> if (!priv)
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
>
> INIT_LIST_HEAD(&priv->maps);
> INIT_LIST_HEAD(&priv->freeable_maps);
> @@ -704,6 +723,32 @@ static int gntdev_open(struct inode *inode, struct file *flip)
> INIT_LIST_HEAD(&priv->dmabuf_imp_list);
> #endif
>
> +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> + priv->dma_dev = dev;
> +
> + /*
> + * The device is not spawn from a device tree, so arch_setup_dma_ops
> + * is not called, thus leaving the device with dummy DMA ops.
> + * Fix this call of_dma_configure() with a NULL node to set
> + * default DMA ops.
> + */
> + of_dma_configure(priv->dma_dev, NULL);
> +#endif
> + pr_debug("priv %p\n", priv);
> +
> + return priv;
> +}
> +EXPORT_SYMBOL(gntdev_alloc_context);
> +
> +static int gntdev_open(struct inode *inode, struct file *flip)
> +{
> + struct gntdev_priv *priv;
> + int ret = 0;
> +
> + priv = gntdev_alloc_context(gntdev_miscdev.this_device);
> + if (IS_ERR(priv))
> + return PTR_ERR(priv);
> +
> if (use_ptemod) {
> priv->mm = get_task_mm(current);
> if (!priv->mm) {
> @@ -716,23 +761,11 @@ static int gntdev_open(struct inode *inode, struct file *flip)
> }
>
> if (ret) {
> - kfree(priv);
> + gntdev_free_context(priv);
> return ret;
> }
>
> flip->private_data = priv;
> -#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> - priv->dma_dev = gntdev_miscdev.this_device;
> -
> - /*
> - * The device is not spawn from a device tree, so arch_setup_dma_ops
> - * is not called, thus leaving the device with dummy DMA ops.
> - * Fix this call of_dma_configure() with a NULL node to set
> - * default DMA ops.
> - */
> - of_dma_configure(priv->dma_dev, NULL);
> -#endif
> - pr_debug("priv %p\n", priv);
>
> return 0;
> }
> @@ -740,22 +773,11 @@ static int gntdev_open(struct inode *inode, struct file *flip)
> static int gntdev_release(struct inode *inode, struct file *flip)
> {
> struct gntdev_priv *priv = flip->private_data;
> - struct grant_map *map;
> -
> - pr_debug("priv %p\n", priv);
> -
> - mutex_lock(&priv->lock);
> - while (!list_empty(&priv->maps)) {
> - map = list_entry(priv->maps.next, struct grant_map, next);
> - list_del(&map->next);
> - gntdev_put_map(NULL /* already removed */, map);
> - }
> - WARN_ON(!list_empty(&priv->freeable_maps));
> - mutex_unlock(&priv->lock);
>
> if (use_ptemod)
> mmu_notifier_unregister(&priv->mn, priv->mm);
> - kfree(priv);
> +
> + gntdev_free_context(priv);
> return 0;
> }
>
> @@ -1210,7 +1232,7 @@ dmabuf_exp_wait_obj_get_by_fd(struct gntdev_priv *priv, int fd)
> return ret;
> }
>
> -static int dmabuf_exp_wait_released(struct gntdev_priv *priv, int fd,
> +int gntdev_dmabuf_exp_wait_released(struct gntdev_priv *priv, int fd,
> int wait_to_ms)
> {
> struct xen_dmabuf *xen_dmabuf;
> @@ -1242,6 +1264,7 @@ static int dmabuf_exp_wait_released(struct gntdev_priv *priv, int fd,
> dmabuf_exp_wait_obj_free(priv, obj);
> return ret;
> }
> +EXPORT_SYMBOL(gntdev_dmabuf_exp_wait_released);
>
> /* ------------------------------------------------------------------ */
> /* DMA buffer export support. */
> @@ -1511,7 +1534,7 @@ dmabuf_exp_alloc_backing_storage(struct gntdev_priv *priv, int dmabuf_flags,
> return map;
> }
>
> -static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
> +int gntdev_dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
> int count, u32 domid, u32 *refs, u32 *fd)
> {
> struct grant_map *map;
> @@ -1557,6 +1580,7 @@ static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
> gntdev_remove_map(priv, map);
> return ret;
> }
> +EXPORT_SYMBOL(gntdev_dmabuf_exp_from_refs);
>
> /* ------------------------------------------------------------------ */
> /* DMA buffer import support. */
> @@ -1646,8 +1670,9 @@ static struct xen_dmabuf *dmabuf_imp_alloc_storage(int count)
> return ERR_PTR(-ENOMEM);
> }
>
> -static struct xen_dmabuf *
> -dmabuf_imp_to_refs(struct gntdev_priv *priv, int fd, int count, int domid)
> +struct xen_dmabuf *
> +gntdev_dmabuf_imp_to_refs(struct gntdev_priv *priv, int fd,
> + int count, int domid)
> {
> struct xen_dmabuf *xen_dmabuf, *ret;
> struct dma_buf *dma_buf;
> @@ -1736,6 +1761,16 @@ dmabuf_imp_to_refs(struct gntdev_priv *priv, int fd, int count, int domid)
> dma_buf_put(dma_buf);
> return ret;
> }
> +EXPORT_SYMBOL(gntdev_dmabuf_imp_to_refs);
> +
> +u32 *gntdev_dmabuf_imp_get_refs(struct xen_dmabuf *xen_dmabuf)
> +{
> + if (xen_dmabuf)
> + return xen_dmabuf->u.imp.refs;
> +
> + return NULL;
> +}
> +EXPORT_SYMBOL(gntdev_dmabuf_imp_get_refs);
>
> /*
> * Find the hyper dma-buf by its file descriptor and remove
> @@ -1759,7 +1794,7 @@ dmabuf_imp_find_unlink(struct gntdev_priv *priv, int fd)
> return ret;
> }
>
> -static int dmabuf_imp_release(struct gntdev_priv *priv, u32 fd)
> +int gntdev_dmabuf_imp_release(struct gntdev_priv *priv, u32 fd)
> {
> struct xen_dmabuf *xen_dmabuf;
> struct dma_buf_attachment *attach;
> @@ -1785,6 +1820,7 @@ static int dmabuf_imp_release(struct gntdev_priv *priv, u32 fd)
> dmabuf_imp_free_storage(xen_dmabuf);
> return 0;
> }
> +EXPORT_SYMBOL(gntdev_dmabuf_imp_release);
>
> /* ------------------------------------------------------------------ */
> /* DMA buffer IOCTL support. */
> @@ -1810,8 +1846,8 @@ gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv,
> goto out;
> }
>
> - ret = dmabuf_exp_from_refs(priv, op.flags, op.count,
> - op.domid, refs, &op.fd);
> + ret = gntdev_dmabuf_exp_from_refs(priv, op.flags, op.count,
> + op.domid, refs, &op.fd);
> if (ret)
> goto out;
>
> @@ -1832,7 +1868,7 @@ gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv,
> if (copy_from_user(&op, u, sizeof(op)) != 0)
> return -EFAULT;
>
> - return dmabuf_exp_wait_released(priv, op.fd, op.wait_to_ms);
> + return gntdev_dmabuf_exp_wait_released(priv, op.fd, op.wait_to_ms);
> }
>
> static long
> @@ -1846,7 +1882,7 @@ gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv,
> if (copy_from_user(&op, u, sizeof(op)) != 0)
> return -EFAULT;
>
> - xen_dmabuf = dmabuf_imp_to_refs(priv, op.fd, op.count, op.domid);
> + xen_dmabuf = gntdev_dmabuf_imp_to_refs(priv, op.fd, op.count, op.domid);
> if (IS_ERR(xen_dmabuf))
> return PTR_ERR(xen_dmabuf);
>
> @@ -1858,7 +1894,7 @@ gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv,
> return 0;
>
> out_release:
> - dmabuf_imp_release(priv, op.fd);
> + gntdev_dmabuf_imp_release(priv, op.fd);
> return ret;
> }
>
> @@ -1871,7 +1907,7 @@ gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv,
> if (copy_from_user(&op, u, sizeof(op)) != 0)
> return -EFAULT;
>
> - return dmabuf_imp_release(priv, op.fd);
> + return gntdev_dmabuf_imp_release(priv, op.fd);
> }
> #endif
>
> diff --git a/include/xen/grant_dev.h b/include/xen/grant_dev.h
> new file mode 100644
> index 000000000000..faccc9170174
> --- /dev/null
> +++ b/include/xen/grant_dev.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> +
> +/*
> + * Grant device kernel API
> + *
> + * Copyright (C) 2018 EPAM Systems Inc.
> + *
> + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
> + */
> +
> +#ifndef _GRANT_DEV_H
> +#define _GRANT_DEV_H
> +
> +#include <linux/types.h>
> +
> +struct device;
> +struct gntdev_priv;
> +#ifdef CONFIG_XEN_GNTDEV_DMABUF
> +struct xen_dmabuf;
> +#endif
> +
> +struct gntdev_priv *gntdev_alloc_context(struct device *dev);
> +void gntdev_free_context(struct gntdev_priv *priv);
> +
> +#ifdef CONFIG_XEN_GNTDEV_DMABUF
> +int gntdev_dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
> + int count, u32 domid, u32 *refs, u32 *fd);
> +int gntdev_dmabuf_exp_wait_released(struct gntdev_priv *priv, int fd,
> + int wait_to_ms);
> +
> +struct xen_dmabuf *gntdev_dmabuf_imp_to_refs(struct gntdev_priv *priv,
> + int fd, int count, int domid);
> +u32 *gntdev_dmabuf_imp_get_refs(struct xen_dmabuf *xen_dmabuf);
> +int gntdev_dmabuf_imp_release(struct gntdev_priv *priv, u32 fd);
> +#endif
> +
> +#endif

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