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Commit c4b712d1 authored by Jose Abreu's avatar Jose Abreu Committed by Greg Kroah-Hartman
Browse files

net: stmmac: Rework stmmac_rx() 



[ Upstream commit 88ebe2cf7f3fc9da95e0f06483fd58da3e67e675 ]

This looks over-engineered. Let's use some helpers to get the buffer
length and hereby simplify the stmmac_rx() function. No performance drop
was seen with the new implementation.

Signed-off-by: default avatarJose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Stable-dep-of: fa02de9e7588 ("net: stmmac: fix rx budget limit check")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent b2762d13

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+94 −52
Original line number Diff line number Diff line
@@ -3440,6 +3440,55 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv, u32 queue) 
	stmmac_set_rx_tail_ptr(priv, priv->ioaddr, rx_q->rx_tail_addr, queue);

}



static unsigned int stmmac_rx_buf1_len(struct stmmac_priv *priv,

				       struct dma_desc *p,

				       int status, unsigned int len)

{

	int ret, coe = priv->hw->rx_csum;

	unsigned int plen = 0, hlen = 0;



	/* Not first descriptor, buffer is always zero */

	if (priv->sph && len)

		return 0;



	/* First descriptor, get split header length */

	ret = stmmac_get_rx_header_len(priv, p, &hlen);

	if (priv->sph && hlen) {

		priv->xstats.rx_split_hdr_pkt_n++;

		return hlen;

	}



	/* First descriptor, not last descriptor and not split header */

	if (status & rx_not_ls)

		return priv->dma_buf_sz;



	plen = stmmac_get_rx_frame_len(priv, p, coe);



	/* First descriptor and last descriptor and not split header */

	return min_t(unsigned int, priv->dma_buf_sz, plen);

}



static unsigned int stmmac_rx_buf2_len(struct stmmac_priv *priv,

				       struct dma_desc *p,

				       int status, unsigned int len)

{

	int coe = priv->hw->rx_csum;

	unsigned int plen = 0;



	/* Not split header, buffer is not available */

	if (!priv->sph)

		return 0;



	/* Not last descriptor */

	if (status & rx_not_ls)

		return priv->dma_buf_sz;



	plen = stmmac_get_rx_frame_len(priv, p, coe);



	/* Last descriptor */

	return plen - len;

}



/**

 * stmmac_rx - manage the receive process

 * @priv: driver private structure
@@ -3469,11 +3518,10 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 
		stmmac_display_ring(priv, rx_head, DMA_RX_SIZE, true);

	}

	while (count < limit) {

		unsigned int hlen = 0, prev_len = 0;

		unsigned int buf1_len = 0, buf2_len = 0;

		enum pkt_hash_types hash_type;

		struct stmmac_rx_buffer *buf;

		struct dma_desc *np, *p;

		unsigned int sec_len;

		int entry;

		u32 hash;
@@ -3492,7 +3540,8 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 
			break;



read_again:

		sec_len = 0;

		buf1_len = 0;

		buf2_len = 0;

		entry = next_entry;

		buf = &rx_q->buf_pool[entry];
@@ -3517,7 +3566,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 
			np = rx_q->dma_rx + next_entry;



		prefetch(np);

		prefetch(page_address(buf->page));



		if (priv->extend_desc)

			stmmac_rx_extended_status(priv, &priv->dev->stats,
@@ -3534,17 +3582,21 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 
			goto read_again;

		if (unlikely(error)) {

			dev_kfree_skb(skb);

			skb = NULL;

			count++;

			continue;

		}



		/* Buffer is good. Go on. */



		if (likely(status & rx_not_ls)) {

			len += priv->dma_buf_sz;

		} else {

			prev_len = len;

			len = stmmac_get_rx_frame_len(priv, p, coe);

		prefetch(page_address(buf->page));

		if (buf->sec_page)

			prefetch(page_address(buf->sec_page));



		buf1_len = stmmac_rx_buf1_len(priv, p, status, len);

		len += buf1_len;

		buf2_len = stmmac_rx_buf2_len(priv, p, status, len);

		len += buf2_len;



		/* ACS is set; GMAC core strips PAD/FCS for IEEE 802.3

		 * Type frames (LLC/LLC-SNAP)
@@ -3554,49 +3606,37 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 
		 * stripped manually.

		 */

		if (unlikely(priv->synopsys_id >= DWMAC_CORE_4_00) ||

			    unlikely(status != llc_snap))

		    unlikely(status != llc_snap)) {

			if (buf2_len)

				buf2_len -= ETH_FCS_LEN;

			else

				buf1_len -= ETH_FCS_LEN;



			len -= ETH_FCS_LEN;

		}



		if (!skb) {

			int ret = stmmac_get_rx_header_len(priv, p, &hlen);



			if (priv->sph && !ret && (hlen > 0)) {

				sec_len = len;

				if (!(status & rx_not_ls))

					sec_len = sec_len - hlen;

				len = hlen;



				prefetch(page_address(buf->sec_page));

				priv->xstats.rx_split_hdr_pkt_n++;

			}



			skb = napi_alloc_skb(&ch->rx_napi, len);

			skb = napi_alloc_skb(&ch->rx_napi, buf1_len);

			if (!skb) {

				priv->dev->stats.rx_dropped++;

				count++;

				continue;

				goto drain_data;

			}



			dma_sync_single_for_cpu(priv->device, buf->addr, len,

						DMA_FROM_DEVICE);

			dma_sync_single_for_cpu(priv->device, buf->addr,

						buf1_len, DMA_FROM_DEVICE);

			skb_copy_to_linear_data(skb, page_address(buf->page),

						len);

			skb_put(skb, len);

						buf1_len);

			skb_put(skb, buf1_len);



			/* Data payload copied into SKB, page ready for recycle */

			page_pool_recycle_direct(rx_q->page_pool, buf->page);

			buf->page = NULL;

		} else {

			unsigned int buf_len = len - prev_len;



			if (likely(status & rx_not_ls))

				buf_len = priv->dma_buf_sz;



		} else if (buf1_len) {

			dma_sync_single_for_cpu(priv->device, buf->addr,

						buf_len, DMA_FROM_DEVICE);

						buf1_len, DMA_FROM_DEVICE);

			skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,

					buf->page, 0, buf_len,

					buf->page, 0, buf1_len,

					priv->dma_buf_sz);



			/* Data payload appended into SKB */
@@ -3604,22 +3644,23 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 
			buf->page = NULL;

		}



		if (sec_len > 0) {

		if (buf2_len) {

			dma_sync_single_for_cpu(priv->device, buf->sec_addr,

						sec_len, DMA_FROM_DEVICE);

						buf2_len, DMA_FROM_DEVICE);

			skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,

					buf->sec_page, 0, sec_len,

					buf->sec_page, 0, buf2_len,

					priv->dma_buf_sz);



			len += sec_len;



			/* Data payload appended into SKB */

			page_pool_release_page(rx_q->page_pool, buf->sec_page);

			buf->sec_page = NULL;

		}



drain_data:

		if (likely(status & rx_not_ls))

			goto read_again;

		if (!skb)

			continue;



		/* Got entire packet into SKB. Finish it. */
@@ -3637,13 +3678,14 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) 


		skb_record_rx_queue(skb, queue);

		napi_gro_receive(&ch->rx_napi, skb);

		skb = NULL;



		priv->dev->stats.rx_packets++;

		priv->dev->stats.rx_bytes += len;

		count++;

	}



	if (status & rx_not_ls) {

	if (status & rx_not_ls || skb) {

		rx_q->state_saved = true;

		rx_q->state.skb = skb;

		rx_q->state.error = error;