libeth: support different types of buffers for Rx

Unlike previous generations, idpf requires more buffer types for optimal
performance. This includes: header buffers, short buffers, and
no-overhead buffers (w/o headroom and tailroom, for TCP zerocopy when
the header split is enabled).
Introduce libeth Rx buffer type and calculate page_pool params
accordingly. All the HW-related details like buffer alignment are still
accounted. For the header buffers, pick 256 bytes as in most places in
the kernel (have you ever seen frames with bigger headers?).

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/net/libeth/rx.h b/include/net/libeth/rx.h
index f29ea3e34c6c..43574bd6612f 100644
--- a/include/net/libeth/rx.h
+++ b/include/net/libeth/rx.h
@@ -17,6 +17,8 @@
 #define LIBETH_MAX_HEADROOM	LIBETH_SKB_HEADROOM
 /* Link layer / L2 overhead: Ethernet, 2 VLAN tags (C + S), FCS */
 #define LIBETH_RX_LL_LEN	(ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN)
+/* Maximum supported L2-L4 header length */
+#define LIBETH_MAX_HEAD		roundup_pow_of_two(max(MAX_HEADER, 256))
 
 /* Always use order-0 pages */
 #define LIBETH_RX_PAGE_ORDER	0
@@ -44,12 +46,26 @@ struct libeth_fqe {
 } __aligned_largest;
 
 /**
+ * enum libeth_fqe_type - enum representing types of Rx buffers
+ * @LIBETH_FQE_MTU: buffer size is determined by MTU
+ * @LIBETH_FQE_SHORT: buffer size is smaller than MTU, for short frames
+ * @LIBETH_FQE_HDR: buffer size is ```LIBETH_MAX_HEAD```-sized, for headers
+ */
+enum libeth_fqe_type {
+	LIBETH_FQE_MTU		= 0U,
+	LIBETH_FQE_SHORT,
+	LIBETH_FQE_HDR,
+};
+
+/**
  * struct libeth_fq - structure representing a buffer (fill) queue
  * @fp: hotpath part of the structure
  * @pp: &page_pool for buffer management
  * @fqes: array of Rx buffers
  * @truesize: size to allocate per buffer, w/overhead
  * @count: number of descriptors/buffers the queue has
+ * @type: type of the buffers this queue has
+ * @hsplit: flag whether header split is enabled
  * @buf_len: HW-writeable length per each buffer
  * @nid: ID of the closest NUMA node with memory
  */
@@ -63,6 +79,9 @@ struct libeth_fq {
 	);
 
 	/* Cold fields */
+	enum libeth_fqe_type	type:2;
+	bool			hsplit:1;
+
 	u32			buf_len;
 	int			nid;
 };