net: lan966x: Split function lan966x_fdma_rx_get_frame

The function lan966x_fdma_rx_get_frame was unmapping the frame from device and check also if the frame was received on a valid port. And only after that it tried to generate the skb. Move this check in a different function, in preparation for xdp support. Such that xdp to be added here and the lan966x_fdma_rx_get_frame to be used only when giving the skb to upper layers. Signed-off-by: Horatiu Vultur <[email protected]> Signed-off-by: David S. Miller <[email protected]>
torvalds · Nov 11, 2022 · 4a00b0c · 4a00b0c
1 parent e83163b
commit 4a00b0c
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Showing 2 changed files with 69 additions and 25 deletions.
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -54,6 +54,17 @@ static void lan966x_fdma_rx_free_pages(struct lan966x_rx *rx)
  }
 }
 
+static void lan966x_fdma_rx_free_page(struct lan966x_rx *rx)
+{
+ struct page *page;
+
+ page = rx->page[rx->dcb_index][rx->db_index];
+ if (unlikely(!page))
+ return;
+
+ __free_pages(page, rx->page_order);
+}
+
 static void lan966x_fdma_rx_add_dcb(struct lan966x_rx *rx,
  struct lan966x_rx_dcb *dcb,
  u64 nextptr)
@@ -116,6 +127,12 @@ static int lan966x_fdma_rx_alloc(struct lan966x_rx *rx)
  return 0;
 }
 
+static void lan966x_fdma_rx_advance_dcb(struct lan966x_rx *rx)
+{
+ rx->dcb_index++;
+ rx->dcb_index &= FDMA_DCB_MAX - 1;
+}
+
 static void lan966x_fdma_rx_free(struct lan966x_rx *rx)
 {
  struct lan966x *lan966x = rx->lan966x;
@@ -403,38 +420,53 @@ static bool lan966x_fdma_rx_more_frames(struct lan966x_rx *rx)
  return true;
 }
 
-static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx)
+static int lan966x_fdma_rx_check_frame(struct lan966x_rx *rx, u64 *src_port)
 {
  struct lan966x *lan966x = rx->lan966x;
- u64 src_port, timestamp;
  struct lan966x_db *db;
- struct sk_buff *skb;
  struct page *page;
 
- /* Get the received frame and unmap it */
  db = &rx->dcbs[rx->dcb_index].db[rx->db_index];
  page = rx->page[rx->dcb_index][rx->db_index];
+ if (unlikely(!page))
+ return FDMA_ERROR;
 
  dma_sync_single_for_cpu(lan966x->dev, (dma_addr_t)db->dataptr,
  FDMA_DCB_STATUS_BLOCKL(db->status),
  DMA_FROM_DEVICE);
 
+ dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr,
+ PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE,
+ DMA_ATTR_SKIP_CPU_SYNC);
+
+ lan966x_ifh_get_src_port(page_address(page), src_port);
+ if (WARN_ON(*src_port >= lan966x->num_phys_ports))
+ return FDMA_ERROR;
+
+ return FDMA_PASS;
+}
+
+static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx,
+ u64 src_port)
+{
+ struct lan966x *lan966x = rx->lan966x;
+ struct lan966x_db *db;
+ struct sk_buff *skb;
+ struct page *page;
+ u64 timestamp;
+
+ /* Get the received frame and unmap it */
+ db = &rx->dcbs[rx->dcb_index].db[rx->db_index];
+ page = rx->page[rx->dcb_index][rx->db_index];
+
  skb = build_skb(page_address(page), PAGE_SIZE << rx->page_order);
  if (unlikely(!skb))
- goto unmap_page;
+ goto free_page;
 
  skb_put(skb, FDMA_DCB_STATUS_BLOCKL(db->status));
 
- lan966x_ifh_get_src_port(skb->data, &src_port);
  lan966x_ifh_get_timestamp(skb->data, &timestamp);
 
- if (WARN_ON(src_port >= lan966x->num_phys_ports))
- goto free_skb;
-
- dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr,
- PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE,
- DMA_ATTR_SKIP_CPU_SYNC);
-
  skb->dev = lan966x->ports[src_port]->dev;
  skb_pull(skb, IFH_LEN_BYTES);
 
@@ -457,12 +489,7 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx)
 
  return skb;
 
-free_skb:
- kfree_skb(skb);
-unmap_page:
- dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr,
- PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE,
- DMA_ATTR_SKIP_CPU_SYNC);
+free_page:
  __free_pages(page, rx->page_order);
 
  return NULL;
@@ -478,6 +505,7 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
  struct sk_buff *skb;
  struct page *page;
  int counter = 0;
+ u64 src_port;
  u64 nextptr;
 
  lan966x_fdma_tx_clear_buf(lan966x, weight);
@@ -487,19 +515,26 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
  if (!lan966x_fdma_rx_more_frames(rx))
  break;
 
- skb = lan966x_fdma_rx_get_frame(rx);
+ counter++;
 
- rx->page[rx->dcb_index][rx->db_index] = NULL;
- rx->dcb_index++;
- rx->dcb_index &= FDMA_DCB_MAX - 1;
+ switch (lan966x_fdma_rx_check_frame(rx, &src_port)) {
+ case FDMA_PASS:
+ break;
+ case FDMA_ERROR:
+ lan966x_fdma_rx_free_page(rx);
+ lan966x_fdma_rx_advance_dcb(rx);
+ goto allocate_new;
+ }
 
+ skb = lan966x_fdma_rx_get_frame(rx, src_port);
+ lan966x_fdma_rx_advance_dcb(rx);
  if (!skb)
- break;
+ goto allocate_new;
 
  napi_gro_receive(&lan966x->napi, skb);
- counter++;
  }
 
+allocate_new:
  /* Allocate new pages and map them */
  while (dcb_reload != rx->dcb_index) {
  db = &rx->dcbs[dcb_reload].db[rx->db_index];

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -100,6 +100,15 @@ enum macaccess_entry_type {
  ENTRYTYPE_MACV6,
 };
 
+/* FDMA return action codes for checking if the frame is valid
+ * FDMA_PASS, frame is valid and can be used
+ * FDMA_ERROR, something went wrong, stop getting more frames
+ */
+enum lan966x_fdma_action {
+ FDMA_PASS = 0,
+ FDMA_ERROR,
+};
+
 struct lan966x_port;
 
 struct lan966x_db {