Re: [PATCH 8/8] xen/gntdev: Expose gntdev's dma-buf API for in-kernel use

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