[PATCH v2 9/9] xen/gntdev: Expose gntdev's dma-buf API for in-kernel use

Oleksandr Andrushchenko
2018-06-01T11:41:32Z

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-dmabuf.c | 6 +++
drivers/xen/gntdev.c | 92 +++++++++++++++++++++++--------------
include/xen/grant_dev.h | 37 +++++++++++++++
3 files changed, 101 insertions(+), 34 deletions(-)
create mode 100644 include/xen/grant_dev.h

diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index b5569a220f03..3890ac9dfab6 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -196,6 +196,7 @@ int gntdev_dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd,
dmabuf_exp_wait_obj_free(priv, obj);
return ret;
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_exp_wait_released);

/* ------------------------------------------------------------------ */
/* DMA buffer export support. */
@@ -621,6 +622,7 @@ gntdev_dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
dma_buf_put(dma_buf);
return ret;
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_imp_to_refs);

u32 *gntdev_dmabuf_imp_get_refs(struct gntdev_dmabuf *gntdev_dmabuf)
{
@@ -629,6 +631,7 @@ u32 *gntdev_dmabuf_imp_get_refs(struct gntdev_dmabuf *gntdev_dmabuf)

return NULL;
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_imp_get_refs);

/*
* Find the hyper dma-buf by its file descriptor and remove
@@ -678,6 +681,7 @@ int gntdev_dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd)
dmabuf_imp_free_storage(gntdev_dmabuf);
return 0;
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_imp_release);

struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)
{
@@ -694,8 +698,10 @@ struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)

return priv;
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_init);

void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv)
{
kfree(priv);
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_fini);
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index cf255d45f20f..63902f5298c9 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -621,14 +621,37 @@ 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);
+
+#ifdef CONFIG_XEN_GNTDEV_DMABUF
+ gntdev_dmabuf_fini(priv->dmabuf_priv);
+#endif
+
+ kfree(priv);
+}
+EXPORT_SYMBOL_GPL(gntdev_free_context);
+
+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);
@@ -637,12 +660,40 @@ static int gntdev_open(struct inode *inode, struct file *flip)
#ifdef CONFIG_XEN_GNTDEV_DMABUF
priv->dmabuf_priv = gntdev_dmabuf_init();
if (IS_ERR(priv->dmabuf_priv)) {
- ret = PTR_ERR(priv->dmabuf_priv);
+ struct gntdev_priv *ret;
+
+ ret = ERR_CAST(priv->dmabuf_priv);
kfree(priv);
return ret;
}
#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_GPL(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) {
@@ -655,23 +706,11 @@ 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;
}
@@ -679,27 +718,11 @@ 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);
-
-#ifdef CONFIG_XEN_GNTDEV_DMABUF
- gntdev_dmabuf_fini(priv->dmabuf_priv);
-#endif

if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);

- kfree(priv);
+ gntdev_free_context(priv);
return 0;
}

@@ -1156,6 +1179,7 @@ int gntdev_dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
gntdev_remove_map(priv, map);
return ret;
}
+EXPORT_SYMBOL_GPL(gntdev_dmabuf_exp_from_refs);

/* ------------------------------------------------------------------ */
/* DMA buffer IOCTL support. */
diff --git a/include/xen/grant_dev.h b/include/xen/grant_dev.h
new file mode 100644
index 000000000000..b7d0abd1ab16
--- /dev/null
+++ b/include/xen/grant_dev.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * 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
--
2.17.0