net: atlantic: Implement xdp control plane

aq_xdp() is a xdp setup callback function for Atlantic driver.
When XDP is attached or detached, the device will be restarted because
it uses different headroom, tailroom, and page order value.

If XDP enabled, it switches default page order value from 0 to 2.
Because the default maximum frame size is still 2K and it needs
additional area for headroom and tailroom.
The total size(headroom + frame size + tailroom) is 2624.
So, 1472Bytes will be always wasted for every frame.
But when order-2 is used, these pages can be used 6 times
with flip strategy.
It means only about 106Bytes per frame will be wasted.

Also, It supports xdp fragment feature.
MTU can be 16K if xdp prog supports xdp fragment.
If not, MTU can not exceed 2K - ETH_HLEN - ETH_FCS.

And a static key is added and It will be used to call the xdp_clean
handler in ->poll(). data plane implementation will be contained
the followed patch.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 22 deletions

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 77e76c9efd32..31a14a0dc25d 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -7,12 +7,16 @@
 
 /* File aq_ring.c: Definition of functions for Rx/Tx rings. */
 
-#include "aq_ring.h"
 #include "aq_nic.h"
 #include "aq_hw.h"
 #include "aq_hw_utils.h"
 #include "aq_ptp.h"
+#include "aq_vec.h"
+#include "aq_main.h"
 
+#include <net/xdp.h>
+#include <linux/filter.h>
+#include <linux/bpf_trace.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 
@@ -27,9 +31,10 @@ static inline void aq_free_rxpage(struct aq_rxpage *rxpage, struct device *dev)
 	rxpage->page = NULL;
 }
 
-static int aq_get_rxpage(struct aq_rxpage *rxpage, unsigned int order,
-			 struct device *dev)
+static int aq_alloc_rxpages(struct aq_rxpage *rxpage, struct aq_ring_s *rx_ring)
 {
+	struct device *dev = aq_nic_get_dev(rx_ring->aq_nic);
+	unsigned int order = rx_ring->page_order;
 	struct page *page;
 	int ret = -ENOMEM;
 	dma_addr_t daddr;
@@ -47,7 +52,7 @@ static int aq_get_rxpage(struct aq_rxpage *rxpage, unsigned int order,
 	rxpage->page = page;
 	rxpage->daddr = daddr;
 	rxpage->order = order;
-	rxpage->pg_off = 0;
+	rxpage->pg_off = rx_ring->page_offset;
 
 	return 0;
 
@@ -58,21 +63,26 @@ err_exit:
 	return ret;
 }
 
-static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf,
-			  int order)
+static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf)
 {
+	unsigned int order = self->page_order;
+	u16 page_offset = self->page_offset;
+	u16 frame_max = self->frame_max;
+	u16 tail_size = self->tail_size;
 	int ret;
 
 	if (rxbuf->rxdata.page) {
 		/* One means ring is the only user and can reuse */
 		if (page_ref_count(rxbuf->rxdata.page) > 1) {
 			/* Try reuse buffer */
-			rxbuf->rxdata.pg_off += AQ_CFG_RX_FRAME_MAX;
-			if (rxbuf->rxdata.pg_off + AQ_CFG_RX_FRAME_MAX <=
-				(PAGE_SIZE << order)) {
+			rxbuf->rxdata.pg_off += frame_max + page_offset +
+						tail_size;
+			if (rxbuf->rxdata.pg_off + frame_max + tail_size <=
+			    (PAGE_SIZE << order)) {
 				u64_stats_update_begin(&self->stats.rx.syncp);
 				self->stats.rx.pg_flips++;
 				u64_stats_update_end(&self->stats.rx.syncp);
+
 			} else {
 				/* Buffer exhausted. We have other users and
 				 * should release this page and realloc
@@ -84,7 +94,7 @@ static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf,
 				u64_stats_update_end(&self->stats.rx.syncp);
 			}
 		} else {
-			rxbuf->rxdata.pg_off = 0;
+			rxbuf->rxdata.pg_off = page_offset;
 			u64_stats_update_begin(&self->stats.rx.syncp);
 			self->stats.rx.pg_reuses++;
 			u64_stats_update_end(&self->stats.rx.syncp);
@@ -92,8 +102,7 @@ static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf,
 	}
 
 	if (!rxbuf->rxdata.page) {
-		ret = aq_get_rxpage(&rxbuf->rxdata, order,
-				    aq_nic_get_dev(self->aq_nic));
+		ret = aq_alloc_rxpages(&rxbuf->rxdata, self);
 		if (ret) {
 			u64_stats_update_begin(&self->stats.rx.syncp);
 			self->stats.rx.alloc_fails++;
@@ -117,6 +126,7 @@ static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
 		err = -ENOMEM;
 		goto err_exit;
 	}
+
 	self->dx_ring = dma_alloc_coherent(aq_nic_get_dev(aq_nic),
 					   self->size * self->dx_size,
 					   &self->dx_ring_pa, GFP_KERNEL);
@@ -172,11 +182,22 @@ struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
 	self->idx = idx;
 	self->size = aq_nic_cfg->rxds;
 	self->dx_size = aq_nic_cfg->aq_hw_caps->rxd_size;
-	self->page_order = fls(AQ_CFG_RX_FRAME_MAX / PAGE_SIZE +
-			       (AQ_CFG_RX_FRAME_MAX % PAGE_SIZE ? 1 : 0)) - 1;
-
-	if (aq_nic_cfg->rxpageorder > self->page_order)
-		self->page_order = aq_nic_cfg->rxpageorder;
+	self->xdp_prog = aq_nic->xdp_prog;
+	self->frame_max = AQ_CFG_RX_FRAME_MAX;
+
+	/* Only order-2 is allowed if XDP is enabled */
+	if (READ_ONCE(self->xdp_prog)) {
+		self->page_offset = AQ_XDP_HEADROOM;
+		self->page_order = AQ_CFG_XDP_PAGEORDER;
+		self->tail_size = AQ_XDP_TAILROOM;
+	} else {
+		self->page_offset = 0;
+		self->page_order = fls(self->frame_max / PAGE_SIZE +
+				       (self->frame_max % PAGE_SIZE ? 1 : 0)) - 1;
+		if (aq_nic_cfg->rxpageorder > self->page_order)
+			self->page_order = aq_nic_cfg->rxpageorder;
+		self->tail_size = 0;
+	}
 
 	self = aq_ring_alloc(self, aq_nic);
 	if (!self) {
@@ -449,7 +470,7 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 			skb_add_rx_frag(skb, 0, buff->rxdata.page,
 					buff->rxdata.pg_off + hdr_len,
 					buff->len - hdr_len,
-					AQ_CFG_RX_FRAME_MAX);
+					self->frame_max);
 			page_ref_inc(buff->rxdata.page);
 		}
 
@@ -469,7 +490,7 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 						buff_->rxdata.page,
 						buff_->rxdata.pg_off,
 						buff_->len,
-						AQ_CFG_RX_FRAME_MAX);
+						self->frame_max);
 				page_ref_inc(buff_->rxdata.page);
 				buff_->is_cleaned = 1;
 
@@ -529,7 +550,6 @@ void aq_ring_hwts_rx_clean(struct aq_ring_s *self, struct aq_nic_s *aq_nic)
 
 int aq_ring_rx_fill(struct aq_ring_s *self)
 {
-	unsigned int page_order = self->page_order;
 	struct aq_ring_buff_s *buff = NULL;
 	int err = 0;
 	int i = 0;
@@ -543,9 +563,9 @@ int aq_ring_rx_fill(struct aq_ring_s *self)
 		buff = &self->buff_ring[self->sw_tail];
 
 		buff->flags = 0U;
-		buff->len = AQ_CFG_RX_FRAME_MAX;
+		buff->len = self->frame_max;
 
-		err = aq_get_rxpages(self, buff, page_order);
+		err = aq_get_rxpages(self, buff);
 		if (err)
 			goto err_exit;