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authorAlexander Duyck <alexander.h.duyck@intel.com>2012-05-11 08:32:40 +0000
committerJeff Kirsher <jeffrey.t.kirsher@intel.com>2012-07-17 02:47:41 -0700
commit3595990a9ccc1b819bfe801940eb05f8a84f253e (patch)
tree8d7af4a336dad7ffbd7bb2a5fa4104d984fafeb8
parente2c28ce76001f01fefb255e0ce1fd6819a2ad1ea (diff)
downloadlinux-linaro-stable-3595990a9ccc1b819bfe801940eb05f8a84f253e.tar.gz
ixgbevf: Cleanup accounting for space needed at start of xmit_frame
This change cleans up the accounting needed at the start of xmit_frame so that we can avoid doing too much work to determine how many descriptors we will need. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: Greg Rose <gregory.v.rose@intel.com> Tested-by: Sibai Li <sibai.li@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
-rw-r--r--drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c46
1 files changed, 24 insertions, 22 deletions
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 75af1920b0f7..855bb21824fe 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -175,10 +175,8 @@ static void ixgbevf_unmap_and_free_tx_resource(struct ixgbevf_adapter *adapter,
#define IXGBE_MAX_DATA_PER_TXD (1 << IXGBE_MAX_TXD_PWR)
/* Tx Descriptors needed, worst case */
-#define TXD_USE_COUNT(S) (((S) >> IXGBE_MAX_TXD_PWR) + \
- (((S) & (IXGBE_MAX_DATA_PER_TXD - 1)) ? 1 : 0))
-#define DESC_NEEDED (TXD_USE_COUNT(IXGBE_MAX_DATA_PER_TXD) /* skb->data */ + \
- MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1) /* for context */
+#define TXD_USE_COUNT(S) DIV_ROUND_UP((S), IXGBE_MAX_DATA_PER_TXD)
+#define DESC_NEEDED (MAX_SKB_FRAGS + 4)
static void ixgbevf_tx_timeout(struct net_device *netdev);
@@ -2932,33 +2930,37 @@ static int ixgbevf_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
unsigned int tx_flags = 0;
u8 hdr_len = 0;
int r_idx = 0, tso;
- int count = 0;
-
- unsigned int f;
+ u16 count = TXD_USE_COUNT(skb_headlen(skb));
+#if PAGE_SIZE > IXGBE_MAX_DATA_PER_TXD
+ unsigned short f;
+#endif
tx_ring = &adapter->tx_ring[r_idx];
+ /*
+ * need: 1 descriptor per page * PAGE_SIZE/IXGBE_MAX_DATA_PER_TXD,
+ * + 1 desc for skb_headlen/IXGBE_MAX_DATA_PER_TXD,
+ * + 2 desc gap to keep tail from touching head,
+ * + 1 desc for context descriptor,
+ * otherwise try next time
+ */
+#if PAGE_SIZE > IXGBE_MAX_DATA_PER_TXD
+ for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+ count += TXD_USE_COUNT(skb_shinfo(skb)->frags[f].size);
+#else
+ count += skb_shinfo(skb)->nr_frags;
+#endif
+ if (ixgbevf_maybe_stop_tx(netdev, tx_ring, count + 3)) {
+ adapter->tx_busy++;
+ return NETDEV_TX_BUSY;
+ }
+
if (vlan_tx_tag_present(skb)) {
tx_flags |= vlan_tx_tag_get(skb);
tx_flags <<= IXGBE_TX_FLAGS_VLAN_SHIFT;
tx_flags |= IXGBE_TX_FLAGS_VLAN;
}
- /* four things can cause us to need a context descriptor */
- if (skb_is_gso(skb) ||
- (skb->ip_summed == CHECKSUM_PARTIAL) ||
- (tx_flags & IXGBE_TX_FLAGS_VLAN))
- count++;
-
- count += TXD_USE_COUNT(skb_headlen(skb));
- for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
- count += TXD_USE_COUNT(skb_frag_size(&skb_shinfo(skb)->frags[f]));
-
- if (ixgbevf_maybe_stop_tx(netdev, tx_ring, count)) {
- adapter->tx_busy++;
- return NETDEV_TX_BUSY;
- }
-
first = tx_ring->next_to_use;
if (skb->protocol == htons(ETH_P_IP))