api: odp_packet_io.h: make pktio handles single instance per device

This patch changes odp_pktio_open() to ensure a one-to-one relationship
between a pktio device an a pktio handle. Attempts to open a device
which is already open will fail, setting errno to -EEXIST to indicate
the reason for the failure. A new API odp_pktio_lookup() is added which
can be used to obtain a handle to an already open device.

Signed-off-by: Stuart Haslam <stuart.haslam@arm.com>
Reviewed-by: Bill Fischofer <bill.fischofer@linaro.org>
Signed-off-by: Mike Holmes <mike.holmes@linaro.org>

1 files changed, 16 insertions, 2 deletions

diff --git a/platform/linux-generic/include/api/odp_packet_io.h b/platform/linux-generic/include/api/odp_packet_io.h
index e4577c378..0c34f2957 100644
--- a/platform/linux-generic/include/api/odp_packet_io.h
+++ b/platform/linux-generic/include/api/odp_packet_io.h
@@ -32,8 +32,13 @@ extern "C" {
 /**
  * Open an ODP packet IO instance
  *
- * @param dev    Packet IO device
- * @param pool   Pool to use for packet IO
+ * Packet IO handles are single instance per device, attempts to open an already
+ * open device will fail, returning ODP_PKTIO_INVALID with errno set to -EEXIST.
+ * odp_pktio_lookup() may be used to obtain a handle to an already open device.
+ *
+ * @param dev    Packet IO device name
+ * @param pool   Pool from which to allocate buffers for storing packets
+ *               received over this packet IO
  *
  * @return ODP packet IO handle or ODP_PKTIO_INVALID on error
  *
@@ -53,6 +58,15 @@ odp_pktio_t odp_pktio_open(const char *dev, odp_buffer_pool_t pool);
 int odp_pktio_close(odp_pktio_t id);
 
 /**
+ * Return a packet IO handle for an already open device
+ *
+ * @param dev Packet IO device name
+ *
+ * @return ODP packet IO handle or ODP_PKTIO_INVALID
+ */
+odp_pktio_t odp_pktio_lookup(const char *dev);
+
+/**
  * Receive packets
  *
  * @param id          ODP packet IO handle