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Commit 8542db05 authored by Alexander Duyck's avatar Alexander Duyck Committed by Jeff Kirsher
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igb: Make first and tx_buffer_info->next_to_watch into pointers 



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: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Tested-by: default avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 7d13a7d0

drivers/net/ethernet/intel/igb/igb.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

drivers/net/ethernet/intel/igb/igb_main.c

+36 −30
Original line number Diff line number Diff line
@@ -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 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb, 
	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,