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Subject[RFC PATCH 44/60] hyper_dmabuf: proper handling of sgt_info->priv
Date
sgt_info->priv will be used to store user private info passed in
ioctl. Data in sgt_info->priv is transfered via comm channel to
the importer VM whenever DMA_BUF is exported to keep the private
data synchroized across VMs.

This patch also adds hyper_dmabuf_send_export_msg that replaces
some of export_remote_ioctl to make it more readable and
compact.

Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c | 110 ++++++++++++++-----------
drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h | 6 +-
2 files changed, 65 insertions(+), 51 deletions(-)

diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
index 3215003..dfdb889 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
@@ -82,17 +82,64 @@ static int hyper_dmabuf_rx_ch_setup_ioctl(struct file *filp, void *data)
return ret;
}

+static int hyper_dmabuf_send_export_msg(struct hyper_dmabuf_sgt_info *sgt_info,
+ struct hyper_dmabuf_pages_info *page_info)
+{
+ struct hyper_dmabuf_backend_ops *ops = hyper_dmabuf_private.backend_ops;
+ struct hyper_dmabuf_req *req;
+ int operands[12] = {0};
+ int ret, i;
+
+ /* now create request for importer via ring */
+ operands[0] = sgt_info->hid.id;
+
+ for (i=0; i<3; i++)
+ operands[i+1] = sgt_info->hid.rng_key[i];
+
+ if (page_info) {
+ operands[4] = page_info->nents;
+ operands[5] = page_info->frst_ofst;
+ operands[6] = page_info->last_len;
+ operands[7] = ops->share_pages (page_info->pages, sgt_info->hyper_dmabuf_rdomain,
+ page_info->nents, &sgt_info->refs_info);
+ if (operands[7] < 0) {
+ dev_err(hyper_dmabuf_private.device, "pages sharing failed\n");
+ return -1;
+ }
+ }
+
+ /* driver/application specific private info, max 4x4 bytes */
+ memcpy(&operands[8], &sgt_info->priv[0], sizeof(unsigned int) * 4);
+
+ req = kcalloc(1, sizeof(*req), GFP_KERNEL);
+
+ if(!req) {
+ dev_err(hyper_dmabuf_private.device, "no more space left\n");
+ return -1;
+ }
+
+ /* composing a message to the importer */
+ hyper_dmabuf_create_request(req, HYPER_DMABUF_EXPORT, &operands[0]);
+
+ ret = ops->send_req(sgt_info->hyper_dmabuf_rdomain, req, false);
+
+ if(ret) {
+ dev_err(hyper_dmabuf_private.device, "error while communicating\n");
+ }
+
+ kfree(req);
+
+ return ret;
+}
+
static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
{
struct ioctl_hyper_dmabuf_export_remote *export_remote_attr;
- struct hyper_dmabuf_backend_ops *ops = hyper_dmabuf_private.backend_ops;
struct dma_buf *dma_buf;
struct dma_buf_attachment *attachment;
struct sg_table *sgt;
struct hyper_dmabuf_pages_info *page_info;
struct hyper_dmabuf_sgt_info *sgt_info;
- struct hyper_dmabuf_req *req;
- int operands[MAX_NUMBER_OF_OPERANDS];
hyper_dmabuf_id_t hid;
int i;
int ret = 0;
@@ -138,6 +185,13 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
}
sgt_info->unexport_scheduled = 0;
}
+
+ /* update private data in sgt_info with new ones */
+ memcpy(&sgt_info->priv[0], &export_remote_attr->priv[0], sizeof(unsigned int) * 4);
+
+ /* TODO: need to send this private info to the importer so that those
+ * on importer's side are also updated */
+
dma_buf_put(dma_buf);
export_remote_attr->hid = hid;
return 0;
@@ -225,6 +279,9 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
INIT_LIST_HEAD(&sgt_info->va_kmapped->list);
INIT_LIST_HEAD(&sgt_info->va_vmapped->list);

+ /* copy private data to sgt_info */
+ memcpy(&sgt_info->priv[0], &export_remote_attr->priv[0], sizeof(unsigned int) * 4);
+
page_info = hyper_dmabuf_ext_pgs(sgt);
if (!page_info) {
dev_err(hyper_dmabuf_private.device, "failed to construct page_info\n");
@@ -236,53 +293,15 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
/* now register it to export list */
hyper_dmabuf_register_exported(sgt_info);

- page_info->hyper_dmabuf_rdomain = sgt_info->hyper_dmabuf_rdomain;
- page_info->hid = sgt_info->hid; /* may not be needed */
-
export_remote_attr->hid = sgt_info->hid;

- /* now create request for importer via ring */
- operands[0] = page_info->hid.id;
-
- for (i=0; i<3; i++)
- operands[i+1] = page_info->hid.rng_key[i];
-
- operands[4] = page_info->nents;
- operands[5] = page_info->frst_ofst;
- operands[6] = page_info->last_len;
- operands[7] = ops->share_pages (page_info->pages, export_remote_attr->remote_domain,
- page_info->nents, &sgt_info->refs_info);
- if (operands[7] < 0) {
- dev_err(hyper_dmabuf_private.device, "pages sharing failed\n");
- goto fail_map_req;
- }
-
- /* driver/application specific private info, max 4x4 bytes */
- operands[8] = export_remote_attr->priv[0];
- operands[9] = export_remote_attr->priv[1];
- operands[10] = export_remote_attr->priv[2];
- operands[11] = export_remote_attr->priv[3];
-
- req = kcalloc(1, sizeof(*req), GFP_KERNEL);
+ ret = hyper_dmabuf_send_export_msg(sgt_info, page_info);

- if(!req) {
- dev_err(hyper_dmabuf_private.device, "no more space left\n");
- goto fail_map_req;
- }
-
- /* composing a message to the importer */
- hyper_dmabuf_create_request(req, HYPER_DMABUF_EXPORT, &operands[0]);
-
- ret = ops->send_req(export_remote_attr->remote_domain, req, false);
-
- if(ret) {
- dev_err(hyper_dmabuf_private.device, "error while communicating\n");
+ if (ret < 0) {
+ dev_err(hyper_dmabuf_private.device, "failed to send out the export request\n");
goto fail_send_request;
}

- /* free msg */
- kfree(req);
-
/* free page_info */
kfree(page_info->pages);
kfree(page_info);
@@ -294,9 +313,6 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
/* Clean-up if error occurs */

fail_send_request:
- kfree(req);
-
-fail_map_req:
hyper_dmabuf_remove_exported(sgt_info->hid);

/* free page_info */
diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h b/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h
index 991a8d4..a1d3ec6 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h
@@ -51,8 +51,6 @@ struct vmap_vaddr_list {

/* Exporter builds pages_info before sharing pages */
struct hyper_dmabuf_pages_info {
- hyper_dmabuf_id_t hid; /* unique id to reference dmabuf in source domain */
- int hyper_dmabuf_rdomain; /* currenting considering just one remote domain access it */
int frst_ofst; /* offset of data in the first page */
int last_len; /* length of data in the last page */
int nents; /* # of pages */
@@ -71,7 +69,7 @@ struct hyper_dmabuf_sgt_info {
int hyper_dmabuf_rdomain; /* domain importing this sgt */

struct dma_buf *dma_buf; /* needed to store this for freeing it later */
- int nents; /* number of pages, which may be different than sgt->nents */
+ int nents;

/* list of remote activities on dma_buf */
struct sgt_list *active_sgts;
@@ -92,7 +90,7 @@ struct hyper_dmabuf_sgt_info {
* uses releases hyper_dmabuf device
*/
struct file *filp;
- int private[4]; /* device specific info (e.g. image's meta info?) */
+ int priv[4]; /* device specific info (e.g. image's meta info?) */
};

/* Importer store references (before mapping) on shared pages
--
2.7.4
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