[RFC PATCH 05/60] hyper_dmabuf: skip creating a comm ch if exist for the VM

From: Dongwon Kim
Date: Tue Dec 19 2017 - 14:51:28 EST


hyper_dmabuf_importer_ring_setup creates new channel only if
there is no existing downstream communication channel previously
created for the exporter VM.

Signed-off-by: Dongwon Kim <dongwon.kim@xxxxxxxxx>
---
drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c | 13 +++++++------
drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c | 20 ++++++++++++++++++++
2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c
index 3b40ec0..6b16e37 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c
@@ -827,12 +827,11 @@ static const struct dma_buf_ops hyper_dmabuf_ops = {
int hyper_dmabuf_export_fd(struct hyper_dmabuf_imported_sgt_info *dinfo, int flags)
{
int fd;
-
struct dma_buf* dmabuf;

-/* call hyper_dmabuf_export_dmabuf and create and bind a handle for it
- * then release */
-
+ /* call hyper_dmabuf_export_dmabuf and create
+ * and bind a handle for it then release
+ */
dmabuf = hyper_dmabuf_export_dma_buf(dinfo);

fd = dma_buf_fd(dmabuf, flags);
@@ -845,9 +844,11 @@ struct dma_buf* hyper_dmabuf_export_dma_buf(struct hyper_dmabuf_imported_sgt_inf
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

exp_info.ops = &hyper_dmabuf_ops;
- exp_info.size = dinfo->sgt->nents * PAGE_SIZE; /* multiple of PAGE_SIZE, not considering offset */
+
+ /* multiple of PAGE_SIZE, not considering offset */
+ exp_info.size = dinfo->sgt->nents * PAGE_SIZE;
exp_info.flags = /* not sure about flag */0;
exp_info.priv = dinfo;

return dma_buf_export(&exp_info);
-};
+}
diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
index 665cada..90e0c65 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
@@ -12,6 +12,7 @@
#include "hyper_dmabuf_drv.h"
#include "hyper_dmabuf_query.h"
#include "xen/hyper_dmabuf_xen_comm.h"
+#include "xen/hyper_dmabuf_xen_comm_list.h"
#include "hyper_dmabuf_msg.h"

struct hyper_dmabuf_private {
@@ -31,6 +32,7 @@ static uint32_t hyper_dmabuf_id_gen(void) {
static int hyper_dmabuf_exporter_ring_setup(void *data)
{
struct ioctl_hyper_dmabuf_exporter_ring_setup *ring_attr;
+ struct hyper_dmabuf_ring_info_export *ring_info;
int ret = 0;

if (!data) {
@@ -39,6 +41,15 @@ static int hyper_dmabuf_exporter_ring_setup(void *data)
}
ring_attr = (struct ioctl_hyper_dmabuf_exporter_ring_setup *)data;

+ /* check if the ring ch already exists */
+ ring_info = hyper_dmabuf_find_exporter_ring(ring_attr->remote_domain);
+
+ if (ring_info) {
+ printk("(exporter's) ring ch to domid = %d already exist\ngref = %d, port = %d\n",
+ ring_info->rdomain, ring_info->gref_ring, ring_info->port);
+ return 0;
+ }
+
ret = hyper_dmabuf_exporter_ringbuf_init(ring_attr->remote_domain,
&ring_attr->ring_refid,
&ring_attr->port);
@@ -49,6 +60,7 @@ static int hyper_dmabuf_exporter_ring_setup(void *data)
static int hyper_dmabuf_importer_ring_setup(void *data)
{
struct ioctl_hyper_dmabuf_importer_ring_setup *setup_imp_ring_attr;
+ struct hyper_dmabuf_ring_info_import *ring_info;
int ret = 0;

if (!data) {
@@ -58,6 +70,14 @@ static int hyper_dmabuf_importer_ring_setup(void *data)

setup_imp_ring_attr = (struct ioctl_hyper_dmabuf_importer_ring_setup *)data;

+ /* check if the ring ch already exist */
+ ring_info = hyper_dmabuf_find_importer_ring(setup_imp_ring_attr->source_domain);
+
+ if (ring_info) {
+ printk("(importer's) ring ch to domid = %d already exist\n", ring_info->sdomain);
+ return 0;
+ }
+
/* user need to provide a port number and ref # for the page used as ring buffer */
ret = hyper_dmabuf_importer_ringbuf_init(setup_imp_ring_attr->source_domain,
setup_imp_ring_attr->ring_refid,
--
2.7.4