netdev - [PATCH V2 net 19/20] net/ena: restructure skb allocation

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Message-Id: <1480857578-5065-20-git-send-email-netanel@annapurnalabs.com>
Date:   Sun,  4 Dec 2016 15:19:37 +0200
From:   Netanel Belgazal <netanel@...apurnalabs.com>
To:     linux-kernel@...r.kernel.org, davem@...emloft.net,
        netdev@...r.kernel.org
Cc:     Netanel Belgazal <netanel@...apurnalabs.com>, dwmw@...zon.com,
        zorik@...apurnalabs.com, alex@...apurnalabs.com,
        saeed@...apurnalabs.com, msw@...zon.com, aliguori@...zon.com,
        nafea@...apurnalabs.com
Subject: [PATCH V2 net 19/20] net/ena: restructure skb allocation

To increase readability, refactor skb allocation to dedicated function
This change does not impact the performance since the compiler optimize
the code and elimitate the if condition.

Signed-off-by: Netanel Belgazal <netanel@...apurnalabs.com>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 46 ++++++++++++++++------------
 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index ee80472..8d42960 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -787,6 +787,28 @@ static int ena_clean_tx_irq(struct ena_ring *tx_ring, u32 budget)
 	return tx_pkts;
 }
 
+static struct sk_buff *ena_alloc_skb(struct ena_ring *rx_ring, bool frags)
+{
+	struct sk_buff *skb;
+
+	if (frags)
+		skb = napi_get_frags(rx_ring->napi);
+	else
+		skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
+						rx_ring->rx_copybreak);
+
+	if (unlikely(!skb)) {
+		u64_stats_update_begin(&rx_ring->syncp);
+		rx_ring->rx_stats.skb_alloc_fail++;
+		u64_stats_update_end(&rx_ring->syncp);
+		netif_err(rx_ring->adapter, rx_err, rx_ring->netdev,
+			  "Failed to allocate skb. frags: %d\n", frags);
+		return NULL;
+	}
+
+	return skb;
+}
+
 static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 				  struct ena_com_rx_buf_info *ena_bufs,
 				  u32 descs,
@@ -795,8 +817,7 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 	struct sk_buff *skb;
 	struct ena_rx_buffer *rx_info =
 		&rx_ring->rx_buffer_info[*next_to_clean];
-	u32 len;
-	u32 buf = 0;
+	u32 len, buf = 0;
 	void *va;
 
 	len = ena_bufs[0].len;
@@ -815,16 +836,9 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 	prefetch(va + NET_IP_ALIGN);
 
 	if (len <= rx_ring->rx_copybreak) {
-		skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
-						rx_ring->rx_copybreak);
-		if (unlikely(!skb)) {
-			u64_stats_update_begin(&rx_ring->syncp);
-			rx_ring->rx_stats.skb_alloc_fail++;
-			u64_stats_update_end(&rx_ring->syncp);
-			netif_err(rx_ring->adapter, rx_err, rx_ring->netdev,
-				  "Failed to allocate skb\n");
+		skb = ena_alloc_skb(rx_ring, false);
+		if (unlikely(!skb))
 			return NULL;
-		}
 
 		netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
 			  "rx allocated small packet. len %d. data_len %d\n",
@@ -848,15 +862,9 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 		return skb;
 	}
 
-	skb = napi_get_frags(rx_ring->napi);
-	if (unlikely(!skb)) {
-		netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
-			  "Failed allocating skb\n");
-		u64_stats_update_begin(&rx_ring->syncp);
-		rx_ring->rx_stats.skb_alloc_fail++;
-		u64_stats_update_end(&rx_ring->syncp);
+	skb = ena_alloc_skb(rx_ring, true);
+	if (unlikely(!skb))
 		return NULL;
-	}
 
 	do {
 		dma_unmap_page(rx_ring->dev,
-- 
2.7.4