Commit fce99e34 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

igb: change the head and tail offsets into pointers 



Since we are writting to the head/tail pointers frequently we might as well
save ourselves some processing time by converting the head and tail offsets
directly to pointers.  This will shave a few cycles off the rx/tx path and
allows us to move one step closer to the rings being a bit more independant of
each other.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 952f72a8

drivers/net/igb/igb.h

+2 −2
Original line number Diff line number Diff line
@@ -178,8 +178,8 @@ struct igb_ring { 
	unsigned int count;            /* number of desc. in the ring */

	u16 next_to_use;

	u16 next_to_clean;

	u16 head;

	u16 tail;

	void __iomem *head;

	void __iomem *tail;

	struct igb_buffer *buffer_info; /* array of buffer info structs */



	u8 queue_index;

drivers/net/igb/igb_main.c

+16 −16
Original line number Diff line number Diff line
@@ -2124,10 +2124,10 @@ static void igb_configure_tx_ring(struct igb_adapter *adapter, 
	                tdba & 0x00000000ffffffffULL);

	wr32(E1000_TDBAH(reg_idx), tdba >> 32);



	ring->head = E1000_TDH(reg_idx);

	ring->tail = E1000_TDT(reg_idx);

	writel(0, hw->hw_addr + ring->tail);

	writel(0, hw->hw_addr + ring->head);

	ring->head = hw->hw_addr + E1000_TDH(reg_idx);

	ring->tail = hw->hw_addr + E1000_TDT(reg_idx);

	writel(0, ring->head);

	writel(0, ring->tail);



	txdctl |= IGB_TX_PTHRESH;

	txdctl |= IGB_TX_HTHRESH << 8;
@@ -2354,10 +2354,10 @@ static void igb_configure_rx_ring(struct igb_adapter *adapter, 
	               ring->count * sizeof(union e1000_adv_rx_desc));



	/* initialize head and tail */

	ring->head = E1000_RDH(reg_idx);

	ring->tail = E1000_RDT(reg_idx);

	writel(0, hw->hw_addr + ring->head);

	writel(0, hw->hw_addr + ring->tail);

	ring->head = hw->hw_addr + E1000_RDH(reg_idx);

	ring->tail = hw->hw_addr + E1000_RDT(reg_idx);

	writel(0, ring->head);

	writel(0, ring->tail);



	/* set descriptor configuration */

	if (adapter->rx_buffer_len < IGB_RXBUFFER_1024) {
@@ -2567,8 +2567,8 @@ static void igb_clean_tx_ring(struct igb_ring *tx_ring) 
	tx_ring->next_to_use = 0;

	tx_ring->next_to_clean = 0;



	writel(0, adapter->hw.hw_addr + tx_ring->head);

	writel(0, adapter->hw.hw_addr + tx_ring->tail);

	writel(0, tx_ring->head);

	writel(0, tx_ring->tail);

}



/**
@@ -2667,8 +2667,8 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring) 
	rx_ring->next_to_clean = 0;

	rx_ring->next_to_use = 0;



	writel(0, adapter->hw.hw_addr + rx_ring->head);

	writel(0, adapter->hw.hw_addr + rx_ring->tail);

	writel(0, rx_ring->head);

	writel(0, rx_ring->tail);

}



/**
@@ -3556,7 +3556,7 @@ static inline void igb_tx_queue_adv(struct igb_adapter *adapter, 
	wmb();



	tx_ring->next_to_use = i;

	writel(i, adapter->hw.hw_addr + tx_ring->tail);

	writel(i, tx_ring->tail);

	/* we need this if more than one processor can write to our tail

	 * at a time, it syncronizes IO on IA64/Altix systems */

	mmiowb();
@@ -4761,8 +4761,8 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) 
				"  jiffies              <%lx>\n"

				"  desc.status          <%x>\n",

				tx_ring->queue_index,

				readl(adapter->hw.hw_addr + tx_ring->head),

				readl(adapter->hw.hw_addr + tx_ring->tail),

				readl(tx_ring->head),

				readl(tx_ring->tail),

				tx_ring->next_to_use,

				tx_ring->next_to_clean,

				tx_ring->buffer_info[i].time_stamp,
@@ -5103,7 +5103,7 @@ no_buffers: 
		 * applicable for weak-ordered memory model archs,

		 * such as IA-64). */

		wmb();

		writel(i, adapter->hw.hw_addr + rx_ring->tail);

		writel(i, rx_ring->tail);

	}

}

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