netdev - [PATCH 15/15]: be2net: Remove unnecessary frag list traversing.

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>] [day] [month] [year] [list]

Message-Id: <20090609.050234.266955391.davem@davemloft.net>
Date:	Tue, 09 Jun 2009 05:02:34 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	netdev@...r.kernel.org
Subject: [PATCH 15/15]: be2net: Remove unnecessary frag list traversing.


This driver does not indicate support for frag lists.

Furthermore, even if it did, the code is walking the frag
lists incorrectly.  The idiom is:

	for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)

but it's doing:

	for (iter = skb_shinfo(skb)->frag_list; iter;
	     iter = skb_shinfo(iter)->frag_list)

which would never work.  And this proves that this driver never
saw an SKB with active frag lists.

So just remove the code altogether and the driver TX path becomes
much simpler.

Signed-off-by: David S. Miller <davem@...emloft.net>
---
 drivers/net/benet/be_main.c |   56 +++++++++++++++++++-----------------------
 1 files changed, 25 insertions(+), 31 deletions(-)

diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 5f17d80..347d002 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -337,13 +337,10 @@ static void be_tx_stats_update(struct be_adapter *adapter,
 /* Determine number of WRB entries needed to xmit data in an skb */
 static u32 wrb_cnt_for_skb(struct sk_buff *skb, bool *dummy)
 {
-	int cnt = 0;
-	while (skb) {
-		if (skb->len > skb->data_len)
-			cnt++;
-		cnt += skb_shinfo(skb)->nr_frags;
-		skb = skb_shinfo(skb)->frag_list;
-	}
+	int cnt = (skb->len > skb->data_len);
+
+	cnt += skb_shinfo(skb)->nr_frags;
+
 	/* to account for hdr wrb */
 	cnt++;
 	if (cnt & 1) {
@@ -409,31 +406,28 @@ static int make_tx_wrbs(struct be_adapter *adapter,
 	hdr = queue_head_node(txq);
 	queue_head_inc(txq);
 
-	while (skb) {
-		if (skb->len > skb->data_len) {
-			int len = skb->len - skb->data_len;
-			busaddr = pci_map_single(pdev, skb->data, len,
-					PCI_DMA_TODEVICE);
-			wrb = queue_head_node(txq);
-			wrb_fill(wrb, busaddr, len);
-			be_dws_cpu_to_le(wrb, sizeof(*wrb));
-			queue_head_inc(txq);
-			copied += len;
-		}
+	if (skb->len > skb->data_len) {
+		int len = skb->len - skb->data_len;
+		busaddr = pci_map_single(pdev, skb->data, len,
+					 PCI_DMA_TODEVICE);
+		wrb = queue_head_node(txq);
+		wrb_fill(wrb, busaddr, len);
+		be_dws_cpu_to_le(wrb, sizeof(*wrb));
+		queue_head_inc(txq);
+		copied += len;
+	}
 
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
-			struct skb_frag_struct *frag =
-				&skb_shinfo(skb)->frags[i];
-			busaddr = pci_map_page(pdev, frag->page,
-					frag->page_offset,
-					frag->size, PCI_DMA_TODEVICE);
-			wrb = queue_head_node(txq);
-			wrb_fill(wrb, busaddr, frag->size);
-			be_dws_cpu_to_le(wrb, sizeof(*wrb));
-			queue_head_inc(txq);
-			copied += frag->size;
-		}
-		skb = skb_shinfo(skb)->frag_list;
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		struct skb_frag_struct *frag =
+			&skb_shinfo(skb)->frags[i];
+		busaddr = pci_map_page(pdev, frag->page,
+				       frag->page_offset,
+				       frag->size, PCI_DMA_TODEVICE);
+		wrb = queue_head_node(txq);
+		wrb_fill(wrb, busaddr, frag->size);
+		be_dws_cpu_to_le(wrb, sizeof(*wrb));
+		queue_head_inc(txq);
+		copied += frag->size;
 	}
 
 	if (dummy_wrb) {
-- 
1.6.3.2

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html