[RFC PATCH 03/60] hyper_dmabuf: re-use dma_buf previously exported if exist

[Dongwon Kim]

Now we re-use dma_buf instead of exporting it via normal process
(including new mappings). For this, hyper_dmabuf list entries can
be searched with "struct dma_buf*". Also, ioctl (export_remote) is
modified to just return hyper_dmabuf_id if the specific dmabuf
has already been exported to the target domain.

This patch also Includes changes in printk calles for debugging.

Signed-off-by: Dongwon Kim <dongwon.kim@xxxxxxxxx>
---
 drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c   | 28 +++++++++++++--------------
 drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c | 17 ++++++++--------
 drivers/xen/hyper_dmabuf/hyper_dmabuf_list.c  |  4 ++--
 drivers/xen/hyper_dmabuf/hyper_dmabuf_list.h  |  2 +-
 4 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c
index faa5c1b..7cb5c35 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c
@@ -532,7 +532,7 @@ static int hyper_dmabuf_ops_attach(struct dma_buf* dmabuf, struct device* dev,
 						HYPER_DMABUF_OPS_ATTACH);
 
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return ret;
@@ -552,7 +552,7 @@ static void hyper_dmabuf_ops_detach(struct dma_buf* dmabuf, struct dma_buf_attac
 						HYPER_DMABUF_OPS_DETACH);
 
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 }
 
@@ -586,7 +586,7 @@ static struct sg_table* hyper_dmabuf_ops_map(struct dma_buf_attachment *attachme
 						HYPER_DMABUF_OPS_MAP);
 
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return st;
@@ -618,7 +618,7 @@ static void hyper_dmabuf_ops_unmap(struct dma_buf_attachment *attachment,
 						HYPER_DMABUF_OPS_UNMAP);
 
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 }
 
@@ -636,7 +636,7 @@ static void hyper_dmabuf_ops_release(struct dma_buf *dmabuf)
 						HYPER_DMABUF_OPS_RELEASE);
 
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 }
 
@@ -653,7 +653,7 @@ static int hyper_dmabuf_ops_begin_cpu_access(struct dma_buf *dmabuf, enum dma_da
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_BEGIN_CPU_ACCESS);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return ret;
@@ -672,7 +672,7 @@ static int hyper_dmabuf_ops_end_cpu_access(struct dma_buf *dmabuf, enum dma_data
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_END_CPU_ACCESS);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return 0;
@@ -691,7 +691,7 @@ static void *hyper_dmabuf_ops_kmap_atomic(struct dma_buf *dmabuf, unsigned long
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_KMAP_ATOMIC);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return NULL; /* for now NULL.. need to return the address of mapped region */
@@ -710,7 +710,7 @@ static void hyper_dmabuf_ops_kunmap_atomic(struct dma_buf *dmabuf, unsigned long
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_KUNMAP_ATOMIC);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 }
 
@@ -727,7 +727,7 @@ static void *hyper_dmabuf_ops_kmap(struct dma_buf *dmabuf, unsigned long pgnum)
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_KMAP);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return NULL; /* for now NULL.. need to return the address of mapped region */
@@ -746,7 +746,7 @@ static void hyper_dmabuf_ops_kunmap(struct dma_buf *dmabuf, unsigned long pgnum,
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_KUNMAP);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 }
 
@@ -763,7 +763,7 @@ static int hyper_dmabuf_ops_mmap(struct dma_buf *dmabuf, struct vm_area_struct *
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_MMAP);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return ret;
@@ -782,7 +782,7 @@ static void *hyper_dmabuf_ops_vmap(struct dma_buf *dmabuf)
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_VMAP);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 
 	return NULL;
@@ -801,7 +801,7 @@ static void hyper_dmabuf_ops_vunmap(struct dma_buf *dmabuf, void *vaddr)
 	ret = hyper_dmabuf_sync_request_and_wait(HYPER_DMABUF_ID_IMPORTER_GET_SDOMAIN_ID(sgt_info->hyper_dmabuf_id),
 						HYPER_DMABUF_OPS_VUNMAP);
 	if (ret < 0) {
-		printk("send dmabuf sync request failed\n");
+		printk("hyper_dmabuf::%s Error:send dmabuf sync request failed\n", __func__);
 	}
 }
 
diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
index 5e50908..665cada 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
@@ -86,27 +86,28 @@ static int hyper_dmabuf_export_remote(void *data)
 	export_remote_attr = (struct ioctl_hyper_dmabuf_export_remote *)data;
 
 	dma_buf = dma_buf_get(export_remote_attr->dmabuf_fd);
+
 	if (!dma_buf) {
 		printk("Cannot get dma buf\n");
 		return -1;
 	}
 
-	attachment = dma_buf_attach(dma_buf, hyper_dmabuf_private.device);
-	if (!attachment) {
-		printk("Cannot get attachment\n");
-		return -1;
-	}
-
 	/* we check if this specific attachment was already exported
 	 * to the same domain and if yes, it returns hyper_dmabuf_id
 	 * of pre-exported sgt */
-	ret = hyper_dmabuf_find_id(attachment, export_remote_attr->remote_domain);
+	ret = hyper_dmabuf_find_id(dma_buf, export_remote_attr->remote_domain);
 	if (ret != -1) {
-		dma_buf_detach(dma_buf, attachment);
 		dma_buf_put(dma_buf);
 		export_remote_attr->hyper_dmabuf_id = ret;
 		return 0;
 	}
+
+	attachment = dma_buf_attach(dma_buf, hyper_dmabuf_private.device);
+	if (!attachment) {
+		printk("Cannot get attachment\n");
+		return -1;
+	}
+
 	/* Clear ret, as that will cause whole ioctl to return failure to userspace, which is not true */
 	ret = 0;
 
diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.c
index 77a7e65..ad2109c 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.c
@@ -65,13 +65,13 @@ struct hyper_dmabuf_sgt_info *hyper_dmabuf_find_exported(int id)
 }
 
 /* search for pre-exported sgt and return id of it if it exist */
-int hyper_dmabuf_find_id(struct dma_buf_attachment *attach, int domid)
+int hyper_dmabuf_find_id(struct dma_buf *dmabuf, int domid)
 {
 	struct hyper_dmabuf_info_entry_exported *info_entry;
 	int bkt;
 
 	hash_for_each(hyper_dmabuf_hash_exported, bkt, info_entry, node)
-		if(info_entry->info->attachment == attach &&
+		if(info_entry->info->attachment->dmabuf == dmabuf &&
 			info_entry->info->hyper_dmabuf_rdomain == domid)
 			return info_entry->info->hyper_dmabuf_id;
 
diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.h b/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.h
index 869cd9a..463a6da 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.h
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_list.h
@@ -25,7 +25,7 @@ int hyper_dmabuf_table_destroy(void);
 int hyper_dmabuf_register_exported(struct hyper_dmabuf_sgt_info *info);
 
 /* search for pre-exported sgt and return id of it if it exist */
-int hyper_dmabuf_find_id(struct dma_buf_attachment *attach, int domid);
+int hyper_dmabuf_find_id(struct dma_buf *dmabuf, int domid);
 
 int hyper_dmabuf_register_imported(struct hyper_dmabuf_imported_sgt_info* info);
 
-- 
2.7.4