netdev - [PATCH net-next 2/3] dpaa2-eth: add rx copybreak support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu,  1 Apr 2021 19:39:55 +0300
From:   Ioana Ciornei <ciorneiioana@...il.com>
To:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org
Cc:     ruxandra.radulescu@....com, Ioana Ciornei <ioana.ciornei@....com>
Subject: [PATCH net-next 2/3] dpaa2-eth: add rx copybreak support

From: Ioana Ciornei <ioana.ciornei@....com>

DMA unmapping, allocating a new buffer and DMA mapping it back on the
refill path is really not that efficient. Proper buffer recycling (page
pool, flipping the page and using the other half) cannot be done for
DPAA2 since it's not a ring based controller but it rather deals with
multiple queues which all get their buffers from the same buffer pool on
Rx.

To circumvent these limitations, add support for Rx copybreak. For small
sized packets instead of creating a skb around the buffer in which the
frame was received, allocate a new sk buffer altogether, copy the
contents of the frame and release the initial page back into the buffer
pool.

Signed-off-by: Ioana Ciornei <ioana.ciornei@....com>
---
 .../net/ethernet/freescale/dpaa2/dpaa2-eth.c  | 36 +++++++++++++++++--
 .../net/ethernet/freescale/dpaa2/dpaa2-eth.h  |  2 ++
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index f545cb99388a..200831b41078 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -418,6 +418,33 @@ static u32 dpaa2_eth_run_xdp(struct dpaa2_eth_priv *priv,
 	return xdp_act;
 }
 
+struct sk_buff *dpaa2_eth_copybreak(struct dpaa2_eth_channel *ch,
+				    const struct dpaa2_fd *fd, void *fd_vaddr)
+{
+	u16 fd_offset = dpaa2_fd_get_offset(fd);
+	u32 fd_length = dpaa2_fd_get_len(fd);
+	struct sk_buff *skb = NULL;
+	unsigned int skb_len;
+
+	if (fd_length > DPAA2_ETH_DEFAULT_COPYBREAK)
+		return NULL;
+
+	skb_len = fd_length + dpaa2_eth_needed_headroom(NULL);
+
+	skb = napi_alloc_skb(&ch->napi, skb_len);
+	if (!skb)
+		return NULL;
+
+	skb_reserve(skb, dpaa2_eth_needed_headroom(NULL));
+	skb_put(skb, fd_length);
+
+	memcpy(skb->data, fd_vaddr + fd_offset, fd_length);
+
+	dpaa2_eth_recycle_buf(ch->priv, ch, dpaa2_fd_get_addr(fd));
+
+	return skb;
+}
+
 /* Main Rx frame processing routine */
 static void dpaa2_eth_rx(struct dpaa2_eth_priv *priv,
 			 struct dpaa2_eth_channel *ch,
@@ -459,9 +486,12 @@ static void dpaa2_eth_rx(struct dpaa2_eth_priv *priv,
 			return;
 		}
 
-		dma_unmap_page(dev, addr, priv->rx_buf_size,
-			       DMA_BIDIRECTIONAL);
-		skb = dpaa2_eth_build_linear_skb(ch, fd, vaddr);
+		skb = dpaa2_eth_copybreak(ch, fd, vaddr);
+		if (!skb) {
+			dma_unmap_page(dev, addr, priv->rx_buf_size,
+				       DMA_BIDIRECTIONAL);
+			skb = dpaa2_eth_build_linear_skb(ch, fd, vaddr);
+		}
 	} else if (fd_format == dpaa2_fd_sg) {
 		WARN_ON(priv->xdp_prog);
 
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
index 9ba31c2706bb..f8d2b4769983 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
@@ -489,6 +489,8 @@ struct dpaa2_eth_trap_data {
 	struct dpaa2_eth_priv *priv;
 };
 
+#define DPAA2_ETH_DEFAULT_COPYBREAK	512
+
 /* Driver private data */
 struct dpaa2_eth_priv {
 	struct net_device *net_dev;
-- 
2.30.0