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Commit 668dda06 authored by Sunil Goutham's avatar Sunil Goutham Committed by David S. Miller
Browse files

net, thunderx: Remove unnecessary rcv buffer start address management 



Since we have moved on to using allocated pages to carve receive
buffers instead of netdev_alloc_skb() there is no need to store
any pointers for later retrieval. Earlier we had to store
skb and skb->data pointers which later are used to handover
received packet to network stack.

This will avoid an unnecessary cache miss as well.

Signed-off-by: default avatarSunil Goutham <sgoutham@cavium.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b45ceb40

drivers/net/ethernet/cavium/thunder/nicvf_queues.c

+9 −40
Original line number Diff line number Diff line
@@ -18,14 +18,6 @@ 
#include "q_struct.h"

#include "nicvf_queues.h"



struct rbuf_info {

	struct page *page;

	void	*data;

	u64	offset;

};



#define GET_RBUF_INFO(x) ((struct rbuf_info *)(x - NICVF_RCV_BUF_ALIGN_BYTES))



/* Poll a register for a specific value */

static int nicvf_poll_reg(struct nicvf *nic, int qidx,

			  u64 reg, int bit_pos, int bits, int val)
@@ -86,8 +78,6 @@ static void nicvf_free_q_desc_mem(struct nicvf *nic, struct q_desc_mem *dmem) 
static inline int nicvf_alloc_rcv_buffer(struct nicvf *nic, gfp_t gfp,

					 u32 buf_len, u64 **rbuf)

{

	u64 data;

	struct rbuf_info *rinfo;

	int order = get_order(buf_len);



	/* Check if request can be accomodated in previous allocated page */
@@ -113,46 +103,28 @@ static inline int nicvf_alloc_rcv_buffer(struct nicvf *nic, gfp_t gfp, 
		nic->rb_page_offset = 0;

	}



	data = (u64)page_address(nic->rb_page) + nic->rb_page_offset;



	/* Align buffer addr to cache line i.e 128 bytes */

	rinfo = (struct rbuf_info *)(data + NICVF_RCV_BUF_ALIGN_LEN(data));

	/* Save page address for reference updation */

	rinfo->page = nic->rb_page;

	/* Store start address for later retrieval */

	rinfo->data = (void *)data;

	/* Store alignment offset */

	rinfo->offset = NICVF_RCV_BUF_ALIGN_LEN(data);

	*rbuf = (u64 *)((u64)page_address(nic->rb_page) + nic->rb_page_offset);



	data += rinfo->offset;



	/* Give next aligned address to hw for DMA */

	*rbuf = (u64 *)(data + NICVF_RCV_BUF_ALIGN_BYTES);

	return 0;

}



/* Retrieve actual buffer start address and build skb for received packet */

/* Build skb around receive buffer */

static struct sk_buff *nicvf_rb_ptr_to_skb(struct nicvf *nic,

					   u64 rb_ptr, int len)

{

	void *data;

	struct sk_buff *skb;

	struct rbuf_info *rinfo;



	rb_ptr = (u64)phys_to_virt(rb_ptr);

	/* Get buffer start address and alignment offset */

	rinfo = GET_RBUF_INFO(rb_ptr);

	data = phys_to_virt(rb_ptr);



	/* Now build an skb to give to stack */

	skb = build_skb(rinfo->data, RCV_FRAG_LEN);

	skb = build_skb(data, RCV_FRAG_LEN);

	if (!skb) {

		put_page(rinfo->page);

		put_page(virt_to_page(data));

		return NULL;

	}



	/* Set correct skb->data */

	skb_reserve(skb, rinfo->offset + NICVF_RCV_BUF_ALIGN_BYTES);



	prefetch((void *)rb_ptr);

	prefetch(skb->data);

	return skb;

}
@@ -196,7 +168,6 @@ static void nicvf_free_rbdr(struct nicvf *nic, struct rbdr *rbdr) 
	int head, tail;

	u64 buf_addr;

	struct rbdr_entry_t *desc;

	struct rbuf_info *rinfo;



	if (!rbdr)

		return;
@@ -212,16 +183,14 @@ static void nicvf_free_rbdr(struct nicvf *nic, struct rbdr *rbdr) 
	while (head != tail) {

		desc = GET_RBDR_DESC(rbdr, head);

		buf_addr = desc->buf_addr << NICVF_RCV_BUF_ALIGN;

		rinfo = GET_RBUF_INFO((u64)phys_to_virt(buf_addr));

		put_page(rinfo->page);

		put_page(virt_to_page(phys_to_virt(buf_addr)));

		head++;

		head &= (rbdr->dmem.q_len - 1);

	}

	/* Free SKB of tail desc */

	desc = GET_RBDR_DESC(rbdr, tail);

	buf_addr = desc->buf_addr << NICVF_RCV_BUF_ALIGN;

	rinfo = GET_RBUF_INFO((u64)phys_to_virt(buf_addr));

	put_page(rinfo->page);

	put_page(virt_to_page(phys_to_virt(buf_addr)));



	/* Free RBDR ring */

	nicvf_free_q_desc_mem(nic, &rbdr->dmem);

drivers/net/ethernet/cavium/thunder/nicvf_queues.h

+2 −8
Original line number Diff line number Diff line
@@ -84,9 +84,7 @@ 
#define RBDR_THRESH		(RCV_BUF_COUNT / 2)

#define DMA_BUFFER_LEN		2048 /* In multiples of 128bytes */

#define RCV_FRAG_LEN	 (SKB_DATA_ALIGN(DMA_BUFFER_LEN + NET_SKB_PAD) + \

			 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + \

			 (NICVF_RCV_BUF_ALIGN_BYTES * 2))

#define RCV_DATA_OFFSET		NICVF_RCV_BUF_ALIGN_BYTES

			 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))



#define MAX_CQES_FOR_TX		((SND_QUEUE_LEN / MIN_SQ_DESC_PER_PKT_XMIT) * \

				 MAX_CQE_PER_PKT_XMIT)
@@ -108,10 +106,6 @@ 
#define NICVF_SQ_BASE_ALIGN_BYTES	128  /* 7 bits */



#define NICVF_ALIGNED_ADDR(ADDR, ALIGN_BYTES)	ALIGN(ADDR, ALIGN_BYTES)

#define NICVF_ADDR_ALIGN_LEN(ADDR, BYTES)\

	(NICVF_ALIGNED_ADDR(ADDR, BYTES) - BYTES)

#define NICVF_RCV_BUF_ALIGN_LEN(X)\

	(NICVF_ALIGNED_ADDR(X, NICVF_RCV_BUF_ALIGN_BYTES) - X)



/* Queue enable/disable */

#define NICVF_SQ_EN		BIT_ULL(19)