vhost: fix async callback return type

The async copy device callbacks are used by async APIs to transfer data
and check completion status. Async APIs return the number of packets
successfully processed to the caller applications and no error
(negative) value is allowed for API return value. Thus, negative return
values from async device callbacks don't have meaningful usage, while
adding overhead in checking the return value validity. This patch change
the callback return values from "int" to "uint32_t" to get aligned with
async API definition.

Fixes: 78639d54563a ("vhost: introduce async enqueue registration API")

Signed-off-by: Patrick Fu <patrick.fu@intel.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/rte_vhost_async.h b/lib/librte_vhost/rte_vhost_async.h
index c8ad8db..cb62845 100644 (file)
--- a/lib/librte_vhost/rte_vhost_async.h
+++ b/lib/librte_vhost/rte_vhost_async.h
@@ -59,9 +59,9 @@ struct rte_vhost_async_channel_ops {
         * @param count
         *  number of elements in the "descs" array
         * @return
-        *  -1 on failure, number of descs processed on success
+        *  number of descs processed
         */
-       int (*transfer_data)(int vid, uint16_t queue_id,
+       uint32_t (*transfer_data)(int vid, uint16_t queue_id,
                struct rte_vhost_async_desc *descs,
                struct rte_vhost_async_status *opaque_data,
                uint16_t count);
@@ -70,15 +70,15 @@ struct rte_vhost_async_channel_ops {
         * @param vid
         *  id of vhost device to check copy completion
         * @param queue_id
-        *  queue id to check copyp completion
+        *  queue id to check copy completion
         * @param opaque_data
         *  buffer to receive the opaque data pair from DMA engine
         * @param max_packets
         *  max number of packets could be completed
         * @return
-        *  -1 on failure, number of iov segments completed on success
+        *  number of iov segments completed
         */
-       int (*check_completed_copies)(int vid, uint16_t queue_id,
+       uint32_t (*check_completed_copies)(int vid, uint16_t queue_id,
                struct rte_vhost_async_status *opaque_data,
                uint16_t max_packets);
 };