mbuf: add Rx timestamp flag and helpers

There is already a dynamic field for timestamp,
used only for Tx scheduling with the dedicated Tx offload flag.
The same field can be used for Rx timestamp filled by drivers.

A new dynamic flag is defined for Rx usage.
A new function wraps the registration of both field and Rx flag.
The type rte_mbuf_timestamp_t is defined for the API users.

After migrating all Rx timestamp usages, it will be possible
to remove the deprecated timestamp field.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: David Marchand <david.marchand@redhat.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>

lib/librte_mbuf/rte_mbuf_dyn.c

@@ -13,6 +13,7 @@
 #include <rte_errno.h>
 #include <rte_malloc.h>
 #include <rte_string_fns.h>
+#include <rte_bitops.h>
 #include <rte_mbuf.h>
 #include <rte_mbuf_dyn.h>
 
@@ -569,3 +570,45 @@ void rte_mbuf_dyn_dump(FILE *out)
 
 	rte_mcfg_tailq_write_unlock();
 }
+
+static int
+rte_mbuf_dyn_timestamp_register(int *field_offset, uint64_t *flag,
+		const char *direction, const char *flag_name)
+{
+	static const struct rte_mbuf_dynfield field_desc = {
+		.name = RTE_MBUF_DYNFIELD_TIMESTAMP_NAME,
+		.size = sizeof(rte_mbuf_timestamp_t),
+		.align = __alignof__(rte_mbuf_timestamp_t),
+	};
+	struct rte_mbuf_dynflag flag_desc = {};
+	int offset;
+
+	offset = rte_mbuf_dynfield_register(&field_desc);
+	if (offset < 0) {
+		RTE_LOG(ERR, MBUF,
+			"Failed to register mbuf field for timestamp\n");
+		return -1;
+	}
+	if (field_offset != NULL)
+		*field_offset = offset;
+
+	strlcpy(flag_desc.name, flag_name, sizeof(flag_desc.name));
+	offset = rte_mbuf_dynflag_register(&flag_desc);
+	if (offset < 0) {
+		RTE_LOG(ERR, MBUF,
+			"Failed to register mbuf flag for %s timestamp\n",
+			direction);
+		return -1;
+	}
+	if (flag != NULL)
+		*flag = RTE_BIT64(offset);
+
+	return 0;
+}
+
+int
+rte_mbuf_dyn_rx_timestamp_register(int *field_offset, uint64_t *rx_flag)
+{
+	return rte_mbuf_dyn_timestamp_register(field_offset, rx_flag,
+			"Rx", RTE_MBUF_DYNFLAG_RX_TIMESTAMP_NAME);
+}

lib/librte_mbuf/rte_mbuf_dyn.h

@@ -258,13 +258,36 @@ void rte_mbuf_dyn_dump(FILE *out);
  * timestamp. The dynamic Tx timestamp flag tells whether the field contains
  * actual timestamp value for the packets being sent, this value can be
  * used by PMD to schedule packet sending.
- *
- * After PKT_RX_TIMESTAMP flag and fixed timestamp field deprecation
- * and obsoleting, the dedicated Rx timestamp flag is supposed to be
- * introduced and the shared dynamic timestamp field will be used
- * to handle the timestamps on receiving datapath as well.
  */
 #define RTE_MBUF_DYNFIELD_TIMESTAMP_NAME "rte_dynfield_timestamp"
+typedef uint64_t rte_mbuf_timestamp_t;
+
+/**
+ * Indicate that the timestamp field in the mbuf was filled by the driver.
+ */
+#define RTE_MBUF_DYNFLAG_RX_TIMESTAMP_NAME "rte_dynflag_rx_timestamp"
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Register dynamic mbuf field and flag for Rx timestamp.
+ *
+ * @param field_offset
+ *   Pointer to the offset of the registered mbuf field, can be NULL.
+ *   The same field is shared for Rx and Tx timestamp.
+ * @param rx_flag
+ *   Pointer to the mask of the registered offload flag, can be NULL.
+ * @return
+ *   0 on success, -1 otherwise.
+ *   Possible values for rte_errno:
+ *   - EEXIST: already registered with different parameters.
+ *   - EPERM: called from a secondary process.
+ *   - ENOENT: no more field or flag available.
+ *   - ENOMEM: allocation failure.
+ */
+__rte_experimental
+int rte_mbuf_dyn_rx_timestamp_register(int *field_offset, uint64_t *rx_flag);
 
 /**
  * When PMD sees the RTE_MBUF_DYNFLAG_TX_TIMESTAMP_NAME flag set on the

lib/librte_mbuf/version.map

@@ -42,6 +42,7 @@ EXPERIMENTAL {
 	rte_mbuf_dynflag_register;
 	rte_mbuf_dynflag_register_bitnum;
 	rte_mbuf_dyn_dump;
+	rte_mbuf_dyn_rx_timestamp_register;
 	rte_pktmbuf_copy;
 	rte_pktmbuf_free_bulk;
 	rte_pktmbuf_pool_create_extbuf;