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Message-ID: <20090914091255.2cda7d24@nehalam>
Date: Mon, 14 Sep 2009 09:12:55 -0700
From: Stephen Hemminger <shemminger@...ux-foundation.org>
To: Mike McCormack <mikem@...g3k.org>,
David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org
Subject: [PATCH alt] sky2: transmit ring accounting
Be more accurate about number of transmit list elements required.
Signed-off-by: Stephen Hemminger <shemminger@...tta.com>
---
Note: this is an optimization, the old code guaranteed more space
than necessary (MAX_SKB_TX_LE was always bigger than needed).
--- a/drivers/net/sky2.c 2009-09-14 08:45:55.730729606 -0700
+++ b/drivers/net/sky2.c 2009-09-14 09:09:42.395712810 -0700
@@ -65,8 +65,8 @@
#define RX_DEF_PENDING RX_MAX_PENDING
/* This is the worst case number of transmit list elements for a single skb:
- VLAN + TSO + CKSUM + Data + skb_frags * DMA */
-#define MAX_SKB_TX_LE (4 + (sizeof(dma_addr_t)/sizeof(u32))*MAX_SKB_FRAGS)
+ VLAN:GSO + CKSUM + Data + skb_frags * DMA */
+#define MAX_SKB_TX_LE (2 + (sizeof(dma_addr_t)/sizeof(u32))*(MAX_SKB_FRAGS+1))
#define TX_MIN_PENDING (MAX_SKB_TX_LE+1)
#define TX_MAX_PENDING 4096
#define TX_DEF_PENDING 127
@@ -1567,11 +1567,13 @@ static unsigned tx_le_req(const struct s
{
unsigned count;
- count = sizeof(dma_addr_t) / sizeof(u32);
- count += skb_shinfo(skb)->nr_frags * count;
+ count = (skb_shinfo(skb)->nr_frags + 1)
+ * (sizeof(dma_addr_t) / sizeof(u32));
if (skb_is_gso(skb))
++count;
+ else if (sizeof(dma_addr_t) == sizeof(u32))
+ ++count; /* possible vlan */
if (skb->ip_summed == CHECKSUM_PARTIAL)
++count;
--
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