[RFC PATCH v2 4/9] hyper_dmabuf: user private data attached to hyper_DMABUF

From: Dongwon Kim
Date: Tue Feb 13 2018 - 20:51:59 EST

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Define a private data (e.g. meta data for the buffer) attached to
each hyper_DMABUF structure. This data is provided by userapace via
export_remote IOCTL and its size can be up to 192 bytes.

Signed-off-by: Dongwon Kim <dongwon.kim@xxxxxxxxx>
Signed-off-by: Mateusz Polrola <mateuszx.potrola@xxxxxxxxx>
---
drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_ioctl.c | 83 ++++++++++++++++++++--
drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.c | 36 +++++++++-
drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.h | 2 +-
.../dma-buf/hyper_dmabuf/hyper_dmabuf_sgl_proc.c | 1 +
drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_struct.h | 12 ++++
include/uapi/linux/hyper_dmabuf.h | 4 ++
6 files changed, 132 insertions(+), 6 deletions(-)

diff --git a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_ioctl.c b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_ioctl.c
index 020a5590a254..168ccf98f710 100644
--- a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_ioctl.c
+++ b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_ioctl.c
@@ -103,6 +103,11 @@ static int send_export_msg(struct exported_sgt_info *exported,
}
}

+ op[8] = exported->sz_priv;
+
+ /* driver/application specific private info */
+ memcpy(&op[9], exported->priv, op[8]);
+
req = kcalloc(1, sizeof(*req), GFP_KERNEL);

if (!req)
@@ -120,8 +125,9 @@ static int send_export_msg(struct exported_sgt_info *exported,

/* Fast path exporting routine in case same buffer is already exported.
*
- * If same buffer is still valid and exist in EXPORT LIST it returns 0 so
- * that remaining normal export process can be skipped.
+ * If same buffer is still valid and exist in EXPORT LIST, it only updates
+ * user-private data for the buffer and returns 0 so that that it can skip
+ * normal export process.
*
* If "unexport" is scheduled for the buffer, it cancels it since the buffer
* is being re-exported.
@@ -129,7 +135,7 @@ static int send_export_msg(struct exported_sgt_info *exported,
* return '1' if reexport is needed, return '0' if succeeds, return
* Kernel error code if something goes wrong
*/
-static int fastpath_export(hyper_dmabuf_id_t hid)
+static int fastpath_export(hyper_dmabuf_id_t hid, int sz_priv, char *priv)
{
int reexport = 1;
int ret = 0;
@@ -155,6 +161,46 @@ static int fastpath_export(hyper_dmabuf_id_t hid)
exported->unexport_sched = false;
}

+ /* if there's any change in size of private data.
+ * we reallocate space for private data with new size
+ */
+ if (sz_priv != exported->sz_priv) {
+ kfree(exported->priv);
+
+ /* truncating size */
+ if (sz_priv > MAX_SIZE_PRIV_DATA)
+ exported->sz_priv = MAX_SIZE_PRIV_DATA;
+ else
+ exported->sz_priv = sz_priv;
+
+ exported->priv = kcalloc(1, exported->sz_priv,
+ GFP_KERNEL);
+
+ if (!exported->priv) {
+ hyper_dmabuf_remove_exported(exported->hid);
+ hyper_dmabuf_cleanup_sgt_info(exported, true);
+ kfree(exported);
+ return -ENOMEM;
+ }
+ }
+
+ /* update private data in sgt_info with new ones */
+ ret = copy_from_user(exported->priv, priv, exported->sz_priv);
+ if (ret) {
+ dev_err(hy_drv_priv->dev,
+ "Failed to load a new private data\n");
+ ret = -EINVAL;
+ } else {
+ /* send an export msg for updating priv in importer */
+ ret = send_export_msg(exported, NULL);
+
+ if (ret < 0) {
+ dev_err(hy_drv_priv->dev,
+ "Failed to send a new private data\n");
+ ret = -EBUSY;
+ }
+ }
+
return ret;
}

@@ -191,7 +237,8 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
export_remote_attr->remote_domain);

if (hid.id != -1) {
- ret = fastpath_export(hid);
+ ret = fastpath_export(hid, export_remote_attr->sz_priv,
+ export_remote_attr->priv);

/* return if fastpath_export succeeds or
* gets some fatal error
@@ -225,6 +272,24 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
goto fail_sgt_info_creation;
}

+ /* possible truncation */
+ if (export_remote_attr->sz_priv > MAX_SIZE_PRIV_DATA)
+ exported->sz_priv = MAX_SIZE_PRIV_DATA;
+ else
+ exported->sz_priv = export_remote_attr->sz_priv;
+
+ /* creating buffer for private data of buffer */
+ if (exported->sz_priv != 0) {
+ exported->priv = kcalloc(1, exported->sz_priv, GFP_KERNEL);
+
+ if (!exported->priv) {
+ ret = -ENOMEM;
+ goto fail_priv_creation;
+ }
+ } else {
+ dev_err(hy_drv_priv->dev, "size is 0\n");
+ }
+
exported->hid = hyper_dmabuf_get_hid();

/* no more exported dmabuf allowed */
@@ -279,6 +344,10 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
INIT_LIST_HEAD(&exported->va_kmapped->list);
INIT_LIST_HEAD(&exported->va_vmapped->list);

+ /* copy private data to sgt_info */
+ ret = copy_from_user(exported->priv, export_remote_attr->priv,
+ exported->sz_priv);
+
if (ret) {
dev_err(hy_drv_priv->dev,
"failed to load private data\n");
@@ -337,6 +406,9 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)

fail_map_active_attached:
kfree(exported->active_sgts);
+ kfree(exported->priv);
+
+fail_priv_creation:
kfree(exported);

fail_map_active_sgts:
@@ -567,6 +639,9 @@ static void delayed_unexport(struct work_struct *work)
/* register hyper_dmabuf_id to the list for reuse */
hyper_dmabuf_store_hid(exported->hid);

+ if (exported->sz_priv > 0 && !exported->priv)
+ kfree(exported->priv);
+
kfree(exported);
}
}
diff --git a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.c b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.c
index 129b2ff2af2b..7176fa8fb139 100644
--- a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.c
+++ b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.c
@@ -60,9 +60,12 @@ void hyper_dmabuf_create_req(struct hyper_dmabuf_req *req,
* op5 : offset of data in the first page
* op6 : length of data in the last page
* op7 : top-level reference number for shared pages
+ * op8 : size of private data (from op9)
+ * op9 ~ : Driver-specific private data
+ * (e.g. graphic buffer's meta info)
*/

- memcpy(&req->op[0], &op[0], 8 * sizeof(int) + op[8]);
+ memcpy(&req->op[0], &op[0], 9 * sizeof(int) + op[8]);
break;

case HYPER_DMABUF_NOTIFY_UNEXPORT:
@@ -116,6 +119,9 @@ static void cmd_process_work(struct work_struct *work)
* op5 : offset of data in the first page
* op6 : length of data in the last page
* op7 : top-level reference number for shared pages
+ * op8 : size of private data (from op9)
+ * op9 ~ : Driver-specific private data
+ * (e.g. graphic buffer's meta info)
*/

/* if nents == 0, it means it is a message only for
@@ -135,6 +141,24 @@ static void cmd_process_work(struct work_struct *work)
break;
}

+ /* if size of new private data is different,
+ * we reallocate it.
+ */
+ if (imported->sz_priv != req->op[8]) {
+ kfree(imported->priv);
+ imported->sz_priv = req->op[8];
+ imported->priv = kcalloc(1, req->op[8],
+ GFP_KERNEL);
+ if (!imported->priv) {
+ /* set it invalid */
+ imported->valid = 0;
+ break;
+ }
+ }
+
+ /* updating priv data */
+ memcpy(imported->priv, &req->op[9], req->op[8]);
+
break;
}

@@ -143,6 +167,14 @@ static void cmd_process_work(struct work_struct *work)
if (!imported)
break;

+ imported->sz_priv = req->op[8];
+ imported->priv = kcalloc(1, req->op[8], GFP_KERNEL);
+
+ if (!imported->priv) {
+ kfree(imported);
+ break;
+ }
+
imported->hid.id = req->op[0];

for (i = 0; i < 3; i++)
@@ -162,6 +194,8 @@ static void cmd_process_work(struct work_struct *work)
dev_dbg(hy_drv_priv->dev, "\tlast len %d\n", req->op[6]);
dev_dbg(hy_drv_priv->dev, "\tgrefid %d\n", req->op[7]);

+ memcpy(imported->priv, &req->op[9], req->op[8]);
+
imported->valid = true;
hyper_dmabuf_register_imported(imported);

diff --git a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.h b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.h
index 59f1528e9b1e..63a39d068d69 100644
--- a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.h
+++ b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_msg.h
@@ -27,7 +27,7 @@
#ifndef __HYPER_DMABUF_MSG_H__
#define __HYPER_DMABUF_MSG_H__

-#define MAX_NUMBER_OF_OPERANDS 8
+#define MAX_NUMBER_OF_OPERANDS 64

struct hyper_dmabuf_req {
unsigned int req_id;
diff --git a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_sgl_proc.c b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_sgl_proc.c
index d92ae13d8a30..9032f89e0cd0 100644
--- a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_sgl_proc.c
+++ b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_sgl_proc.c
@@ -251,6 +251,7 @@ int hyper_dmabuf_cleanup_sgt_info(struct exported_sgt_info *exported,
kfree(exported->active_attached);
kfree(exported->va_kmapped);
kfree(exported->va_vmapped);
+ kfree(exported->priv);

return 0;
}
diff --git a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_struct.h b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_struct.h
index 144e3821fbc2..a1220bbf8d0c 100644
--- a/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_struct.h
+++ b/drivers/dma-buf/hyper_dmabuf/hyper_dmabuf_struct.h
@@ -101,6 +101,12 @@ struct exported_sgt_info {
* the buffer can be completely freed.
*/
struct file *filp;
+
+ /* size of private */
+ size_t sz_priv;
+
+ /* private data associated with the exported buffer */
+ char *priv;
};

/* imported_sgt_info contains information about imported DMA_BUF
@@ -126,6 +132,12 @@ struct imported_sgt_info {
void *refs_info;
bool valid;
int importers;
+
+ /* size of private */
+ size_t sz_priv;
+
+ /* private data associated with the exported buffer */
+ char *priv;
};

#endif /* __HYPER_DMABUF_STRUCT_H__ */
diff --git a/include/uapi/linux/hyper_dmabuf.h b/include/uapi/linux/hyper_dmabuf.h
index caaae2da9d4d..36794a4af811 100644
--- a/include/uapi/linux/hyper_dmabuf.h
+++ b/include/uapi/linux/hyper_dmabuf.h
@@ -25,6 +25,8 @@
#ifndef __LINUX_PUBLIC_HYPER_DMABUF_H__
#define __LINUX_PUBLIC_HYPER_DMABUF_H__

+#define MAX_SIZE_PRIV_DATA 192
+
typedef struct {
int id;
int rng_key[3]; /* 12bytes long random number */
@@ -56,6 +58,8 @@ struct ioctl_hyper_dmabuf_export_remote {
int remote_domain;
/* exported dma buf id */
hyper_dmabuf_id_t hid;
+ int sz_priv;
+ char *priv;
};

#define IOCTL_HYPER_DMABUF_EXPORT_FD \
--
2.16.1

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