Commit 3a69ab87 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'ionic-better-tx-sg=handling' 



Shannon Nelson says:

====================
ionic: better Tx SG handling

The primary patch here is to be sure we're not hitting linearize on a Tx
skb when we don't really need to.  The other two are related details.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 4fa7011d 529cdfd5

drivers/net/ethernet/pensando/ionic/ionic_dev.h

+2 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/atomic.h>

#include <linux/mutex.h>

#include <linux/workqueue.h>

#include <linux/skbuff.h>



#include "ionic_if.h"

#include "ionic_regs.h"
@@ -216,7 +217,7 @@ struct ionic_desc_info { 
	};

	unsigned int bytes;

	unsigned int nbufs;

	struct ionic_buf_info bufs[IONIC_MAX_FRAGS];

	struct ionic_buf_info bufs[MAX_SKB_FRAGS + 1];

	ionic_desc_cb cb;

	void *cb_arg;

};

drivers/net/ethernet/pensando/ionic/ionic_lif.c

+12 −0
Original line number Diff line number Diff line
@@ -3831,6 +3831,18 @@ static void ionic_lif_queue_identify(struct ionic_lif *lif) 
			qtype, qti->max_sg_elems);

		dev_dbg(ionic->dev, " qtype[%d].sg_desc_stride = %d\n",

			qtype, qti->sg_desc_stride);



		if (qti->max_sg_elems >= IONIC_MAX_FRAGS) {

			qti->max_sg_elems = IONIC_MAX_FRAGS - 1;

			dev_dbg(ionic->dev, "limiting qtype %d max_sg_elems to IONIC_MAX_FRAGS-1 %d\n",

				qtype, qti->max_sg_elems);

		}



		if (qti->max_sg_elems > MAX_SKB_FRAGS) {

			qti->max_sg_elems = MAX_SKB_FRAGS;

			dev_dbg(ionic->dev, "limiting qtype %d max_sg_elems to MAX_SKB_FRAGS %d\n",

				qtype, qti->max_sg_elems);

		}

	}

}

drivers/net/ethernet/pensando/ionic/ionic_txrx.c

+68 −9
Original line number Diff line number Diff line
@@ -1239,25 +1239,84 @@ static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb) 
static int ionic_tx_descs_needed(struct ionic_queue *q, struct sk_buff *skb)

{

	struct ionic_tx_stats *stats = q_to_tx_stats(q);

	bool too_many_frags = false;

	skb_frag_t *frag;

	int desc_bufs;

	int chunk_len;

	int frag_rem;

	int tso_rem;

	int seg_rem;

	bool encap;

	int hdrlen;

	int ndescs;

	int err;



	/* Each desc is mss long max, so a descriptor for each gso_seg */

	if (skb_is_gso(skb))

	if (skb_is_gso(skb)) {

		ndescs = skb_shinfo(skb)->gso_segs;

	else

	} else {

		ndescs = 1;

		if (skb_shinfo(skb)->nr_frags > q->max_sg_elems) {

			too_many_frags = true;

			goto linearize;

		}

	}



	/* If non-TSO, just need 1 desc and nr_frags sg elems */

	if (skb_shinfo(skb)->nr_frags <= q->max_sg_elems)

	/* If non-TSO, or no frags to check, we're done */

	if (!skb_is_gso(skb) || !skb_shinfo(skb)->nr_frags)

		return ndescs;



	/* Too many frags, so linearize */

	/* We need to scan the skb to be sure that none of the MTU sized

	 * packets in the TSO will require more sgs per descriptor than we

	 * can support.  We loop through the frags, add up the lengths for

	 * a packet, and count the number of sgs used per packet.

	 */

	tso_rem = skb->len;

	frag = skb_shinfo(skb)->frags;

	encap = skb->encapsulation;



	/* start with just hdr in first part of first descriptor */

	if (encap)

		hdrlen = skb_inner_tcp_all_headers(skb);

	else

		hdrlen = skb_tcp_all_headers(skb);

	seg_rem = min_t(int, tso_rem, hdrlen + skb_shinfo(skb)->gso_size);

	frag_rem = hdrlen;



	while (tso_rem > 0) {

		desc_bufs = 0;

		while (seg_rem > 0) {

			desc_bufs++;



			/* We add the +1 because we can take buffers for one

			 * more than we have SGs: one for the initial desc data

			 * in addition to the SG segments that might follow.

			 */

			if (desc_bufs > q->max_sg_elems + 1) {

				too_many_frags = true;

				goto linearize;

			}



			if (frag_rem == 0) {

				frag_rem = skb_frag_size(frag);

				frag++;

			}

			chunk_len = min(frag_rem, seg_rem);

			frag_rem -= chunk_len;

			tso_rem -= chunk_len;

			seg_rem -= chunk_len;

		}



		seg_rem = min_t(int, tso_rem, skb_shinfo(skb)->gso_size);

	}



linearize:

	if (too_many_frags) {

		err = skb_linearize(skb);

		if (err)

			return err;



		stats->linearize++;

	}



	return ndescs;

}