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Date: Fri, 7 Oct 2011 00:18:42 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Alexander Duyck <alexander.h.duyck@...el.com>,
netdev@...r.kernel.org, gospo@...hat.com, sassmann@...hat.com,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 09/13] igb: Make first and tx_buffer_info->next_to_watch into pointers
From: Alexander Duyck <alexander.h.duyck@...el.com>
This change converts two tx_buffer_info index values into pointers. The
advantage to this is that we reduce unnecessary computations and in the case
of next_to_watch we get an added bonus of the value being able to provide
additional information as a NULL value indicates it is unset versus a 0 not
having any meaning for the index value.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
Tested-by: Aaron Brown <aaron.f.brown@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/igb/igb.h | 2 +-
drivers/net/ethernet/intel/igb/igb_main.c | 66 ++++++++++++++++-------------
2 files changed, 37 insertions(+), 31 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 56c68fc..7185667 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -133,7 +133,7 @@ struct vf_data_storage {
/* wrapper around a pointer to a socket buffer,
* so a DMA handle can be stored along with the buffer */
struct igb_tx_buffer {
- u16 next_to_watch;
+ union e1000_adv_tx_desc *next_to_watch;
unsigned long time_stamp;
dma_addr_t dma;
u32 length;
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index a0bb81d..edc2cae 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -381,7 +381,7 @@ static void igb_dump(struct igb_adapter *adapter)
struct igb_tx_buffer *buffer_info;
tx_ring = adapter->tx_ring[n];
buffer_info = &tx_ring->tx_buffer_info[tx_ring->next_to_clean];
- printk(KERN_INFO " %5d %5X %5X %016llX %04X %3X %016llX\n",
+ printk(KERN_INFO " %5d %5X %5X %016llX %04X %p %016llX\n",
n, tx_ring->next_to_use, tx_ring->next_to_clean,
(u64)buffer_info->dma,
buffer_info->length,
@@ -421,7 +421,7 @@ static void igb_dump(struct igb_adapter *adapter)
buffer_info = &tx_ring->tx_buffer_info[i];
u0 = (struct my_u0 *)tx_desc;
printk(KERN_INFO "T [0x%03X] %016llX %016llX %016llX"
- " %04X %3X %016llX %p", i,
+ " %04X %p %016llX %p", i,
le64_to_cpu(u0->a),
le64_to_cpu(u0->b),
(u64)buffer_info->dma,
@@ -3161,7 +3161,7 @@ void igb_unmap_and_free_tx_resource(struct igb_ring *tx_ring,
}
buffer_info->time_stamp = 0;
buffer_info->length = 0;
- buffer_info->next_to_watch = 0;
+ buffer_info->next_to_watch = NULL;
buffer_info->mapped_as_page = false;
}
@@ -4107,7 +4107,7 @@ static inline bool igb_tx_csum(struct igb_ring *tx_ring,
#define IGB_MAX_DATA_PER_TXD (1<<IGB_MAX_TXD_PWR)
static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
- unsigned int first)
+ struct igb_tx_buffer *first)
{
struct igb_tx_buffer *buffer_info;
struct device *dev = tx_ring->dev;
@@ -4121,7 +4121,6 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
buffer_info = &tx_ring->tx_buffer_info[i];
BUG_ON(hlen >= IGB_MAX_DATA_PER_TXD);
buffer_info->length = hlen;
- buffer_info->next_to_watch = i;
buffer_info->dma = dma_map_single(dev, skb->data, hlen,
DMA_TO_DEVICE);
if (dma_mapping_error(dev, buffer_info->dma))
@@ -4139,7 +4138,6 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
buffer_info = &tx_ring->tx_buffer_info[i];
BUG_ON(len >= IGB_MAX_DATA_PER_TXD);
buffer_info->length = len;
- buffer_info->next_to_watch = i;
buffer_info->mapped_as_page = true;
buffer_info->dma = skb_frag_dma_map(dev, frag, 0, len,
DMA_TO_DEVICE);
@@ -4153,8 +4151,12 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
/* multiply data chunks by size of headers */
buffer_info->bytecount = ((gso_segs - 1) * hlen) + skb->len;
buffer_info->gso_segs = gso_segs;
- tx_ring->tx_buffer_info[first].next_to_watch = i;
- tx_ring->tx_buffer_info[first].time_stamp = jiffies;
+
+ /* set the timestamp */
+ first->time_stamp = jiffies;
+
+ /* set next_to_watch value indicating a packet is present */
+ first->next_to_watch = IGB_TX_DESC(tx_ring, i);
return ++count;
@@ -4165,7 +4167,6 @@ dma_error:
buffer_info->dma = 0;
buffer_info->time_stamp = 0;
buffer_info->length = 0;
- buffer_info->next_to_watch = 0;
buffer_info->mapped_as_page = false;
/* clear timestamp and dma mappings for remaining portion of packet */
@@ -4283,9 +4284,9 @@ static inline int igb_maybe_stop_tx(struct igb_ring *tx_ring, int size)
netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
struct igb_ring *tx_ring)
{
+ struct igb_tx_buffer *first;
int tso, count;
u32 tx_flags = 0;
- u16 first;
u8 hdr_len = 0;
/* need: 1 descriptor per page,
@@ -4311,7 +4312,8 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
if (skb->protocol == htons(ETH_P_IP))
tx_flags |= IGB_TX_FLAGS_IPV4;
- first = tx_ring->next_to_use;
+ /* record the location of the first descriptor for this packet */
+ first = &tx_ring->tx_buffer_info[tx_ring->next_to_use];
tso = igb_tso(tx_ring, skb, tx_flags, &hdr_len);
@@ -4330,8 +4332,8 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
count = igb_tx_map(tx_ring, skb, first);
if (!count) {
dev_kfree_skb_any(skb);
- tx_ring->tx_buffer_info[first].time_stamp = 0;
- tx_ring->next_to_use = first;
+ first->time_stamp = 0;
+ tx_ring->next_to_use = first - tx_ring->tx_buffer_info;
return NETDEV_TX_OK;
}
@@ -5568,29 +5570,34 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector)
struct igb_adapter *adapter = q_vector->adapter;
struct igb_ring *tx_ring = q_vector->tx_ring;
struct igb_tx_buffer *tx_buffer;
- union e1000_adv_tx_desc *tx_desc;
+ union e1000_adv_tx_desc *tx_desc, *eop_desc;
unsigned int total_bytes = 0, total_packets = 0;
unsigned int budget = q_vector->tx_work_limit;
- u16 i = tx_ring->next_to_clean;
+ unsigned int i = tx_ring->next_to_clean;
if (test_bit(__IGB_DOWN, &adapter->state))
return true;
tx_buffer = &tx_ring->tx_buffer_info[i];
tx_desc = IGB_TX_DESC(tx_ring, i);
+ i -= tx_ring->count;
for (; budget; budget--) {
- u16 eop = tx_buffer->next_to_watch;
- union e1000_adv_tx_desc *eop_desc;
+ eop_desc = tx_buffer->next_to_watch;
- eop_desc = IGB_TX_DESC(tx_ring, eop);
+ /* prevent any other reads prior to eop_desc */
+ rmb();
+
+ /* if next_to_watch is not set then there is no work pending */
+ if (!eop_desc)
+ break;
/* if DD is not set pending work has not been completed */
if (!(eop_desc->wb.status & cpu_to_le32(E1000_TXD_STAT_DD)))
break;
- /* prevent any other reads prior to eop_desc being verified */
- rmb();
+ /* clear next_to_watch to prevent false hangs */
+ tx_buffer->next_to_watch = NULL;
do {
tx_desc->wb.status = 0;
@@ -5607,14 +5614,15 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector)
tx_buffer++;
tx_desc++;
i++;
- if (unlikely(i == tx_ring->count)) {
- i = 0;
+ if (unlikely(!i)) {
+ i -= tx_ring->count;
tx_buffer = tx_ring->tx_buffer_info;
tx_desc = IGB_TX_DESC(tx_ring, 0);
}
} while (eop_desc);
}
+ i += tx_ring->count;
tx_ring->next_to_clean = i;
u64_stats_update_begin(&tx_ring->tx_syncp);
tx_ring->tx_stats.bytes += total_bytes;
@@ -5625,16 +5633,14 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector)
if (tx_ring->detect_tx_hung) {
struct e1000_hw *hw = &adapter->hw;
- u16 eop = tx_ring->tx_buffer_info[i].next_to_watch;
- union e1000_adv_tx_desc *eop_desc;
- eop_desc = IGB_TX_DESC(tx_ring, eop);
+ eop_desc = tx_buffer->next_to_watch;
/* Detect a transmit hang in hardware, this serializes the
* check with the clearing of time_stamp and movement of i */
tx_ring->detect_tx_hung = false;
- if (tx_ring->tx_buffer_info[i].time_stamp &&
- time_after(jiffies, tx_ring->tx_buffer_info[i].time_stamp +
+ if (eop_desc &&
+ time_after(jiffies, tx_buffer->time_stamp +
(adapter->tx_timeout_factor * HZ)) &&
!(rd32(E1000_STATUS) & E1000_STATUS_TXOFF)) {
@@ -5648,7 +5654,7 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector)
" next_to_clean <%x>\n"
"buffer_info[next_to_clean]\n"
" time_stamp <%lx>\n"
- " next_to_watch <%x>\n"
+ " next_to_watch <%p>\n"
" jiffies <%lx>\n"
" desc.status <%x>\n",
tx_ring->queue_index,
@@ -5656,8 +5662,8 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector)
readl(tx_ring->tail),
tx_ring->next_to_use,
tx_ring->next_to_clean,
- tx_ring->tx_buffer_info[eop].time_stamp,
- eop,
+ tx_buffer->time_stamp,
+ eop_desc,
jiffies,
eop_desc->wb.status);
netif_stop_subqueue(tx_ring->netdev,
--
1.7.6.4
--
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