Merge branch 'cxgb4-next'

Hariprasad Shenai says:

====================
cxgb4: Misc. fixes for sge

Increases value of MAX_IMM_TX_PKT_LEN to improve latency, fill freelist
starving threshold based on adapter type, add comments for tx flits and sge
length code and don't call t4_slow_intr_handler when we are not master PF.

This patch series has been created against net-next tree and includes patches on
cxgb4 driver

We have included all the maintainers of respective drivers. Kindly review the
change and let us know in case of any review comments.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -724,6 +724,7 @@ static irqreturn_t t4_nondata_intr(int irq, void *cookie)
 		adap->swintr = 1;
 		t4_write_reg(adap, MYPF_REG(PL_PF_INT_CAUSE_A), v);
 	}
+	if (adap->flags & MASTER_PF)
 		t4_slow_intr_handler(adap);
 	return IRQ_HANDLED;
 }

drivers/net/ethernet/chelsio/cxgb4/sge.c

@@ -120,12 +120,6 @@
  */
 #define NOMEM_TMR_IDX (SGE_NTIMERS - 1)
 
-/*
- * An FL with <= FL_STARVE_THRES buffers is starving and a periodic timer will
- * attempt to refill it.
- */
-#define FL_STARVE_THRES 4
-
 /*
  * Suspend an Ethernet Tx queue with fewer available descriptors than this.
  * This is the same as calc_tx_descs() for a TSO packet with
@@ -144,7 +138,7 @@
  * Max Tx descriptor space we allow for an Ethernet packet to be inlined
  * into a WR.
  */
-#define MAX_IMM_TX_PKT_LEN 128
+#define MAX_IMM_TX_PKT_LEN 256
 
 /*
  * Max size of a WR sent through a control Tx queue.
@@ -248,9 +242,21 @@ static inline unsigned int fl_cap(const struct sge_fl *fl)
 	return fl->size - 8;   /* 1 descriptor = 8 buffers */
 }
 
-static inline bool fl_starving(const struct sge_fl *fl)
+/**
+ *	fl_starving - return whether a Free List is starving.
+ *	@adapter: pointer to the adapter
+ *	@fl: the Free List
+ *
+ *	Tests specified Free List to see whether the number of buffers
+ *	available to the hardware has falled below our "starvation"
+ *	threshold.
+ */
+static inline bool fl_starving(const struct adapter *adapter,
+			       const struct sge_fl *fl)
 {
-	return fl->avail - fl->pend_cred <= FL_STARVE_THRES;
+	const struct sge *s = &adapter->sge;
+
+	return fl->avail - fl->pend_cred <= s->fl_starve_thres;
 }
 
 static int map_skb(struct device *dev, const struct sk_buff *skb,
@@ -586,8 +592,10 @@ static unsigned int refill_fl(struct adapter *adap, struct sge_fl *q, int n,
 	unsigned int cred = q->avail;
 	__be64 *d = &q->desc[q->pidx];
 	struct rx_sw_desc *sd = &q->sdesc[q->pidx];
+	int node;
 
 	gfp |= __GFP_NOWARN;
+	node = dev_to_node(adap->pdev_dev);
 
 	if (s->fl_pg_order == 0)
 		goto alloc_small_pages;
@@ -596,7 +604,7 @@ static unsigned int refill_fl(struct adapter *adap, struct sge_fl *q, int n,
 	 * Prefer large buffers
 	 */
 	while (n) {
-		pg = __dev_alloc_pages(gfp, s->fl_pg_order);
+		pg = alloc_pages_node(node, gfp | __GFP_COMP, s->fl_pg_order);
 		if (unlikely(!pg)) {
 			q->large_alloc_failed++;
 			break;       /* fall back to single pages */
@@ -626,7 +634,7 @@ static unsigned int refill_fl(struct adapter *adap, struct sge_fl *q, int n,
 
 alloc_small_pages:
 	while (n--) {
-		pg = __dev_alloc_page(gfp);
+		pg = alloc_pages_node(node, gfp, 0);
 		if (unlikely(!pg)) {
 			q->alloc_failed++;
 			break;
@@ -655,7 +663,7 @@ out:	cred = q->avail - cred;
 	q->pend_cred += cred;
 	ring_fl_db(adap, q);
 
-	if (unlikely(fl_starving(q))) {
+	if (unlikely(fl_starving(adap, q))) {
 		smp_wmb();
 		set_bit(q->cntxt_id - adap->sge.egr_start,
 			adap->sge.starving_fl);
@@ -722,6 +730,22 @@ static void *alloc_ring(struct device *dev, size_t nelem, size_t elem_size,
  */
 static inline unsigned int sgl_len(unsigned int n)
 {
+	/* A Direct Scatter Gather List uses 32-bit lengths and 64-bit PCI DMA
+	 * addresses.  The DSGL Work Request starts off with a 32-bit DSGL
+	 * ULPTX header, then Length0, then Address0, then, for 1 <= i <= N,
+	 * repeated sequences of { Length[i], Length[i+1], Address[i],
+	 * Address[i+1] } (this ensures that all addresses are on 64-bit
+	 * boundaries).  If N is even, then Length[N+1] should be set to 0 and
+	 * Address[N+1] is omitted.
+	 *
+	 * The following calculation incorporates all of the above.  It's
+	 * somewhat hard to follow but, briefly: the "+2" accounts for the
+	 * first two flits which include the DSGL header, Length0 and
+	 * Address0; the "(3*(n-1))/2" covers the main body of list entries (3
+	 * flits for every pair of the remaining N) +1 if (n-1) is odd; and
+	 * finally the "+((n-1)&1)" adds the one remaining flit needed if
+	 * (n-1) is odd ...
+	 */
 	n--;
 	return (3 * n) / 2 + (n & 1) + 2;
 }
@@ -769,12 +793,30 @@ static inline unsigned int calc_tx_flits(const struct sk_buff *skb)
 	unsigned int flits;
 	int hdrlen = is_eth_imm(skb);
 
+	/* If the skb is small enough, we can pump it out as a work request
+	 * with only immediate data.  In that case we just have to have the
+	 * TX Packet header plus the skb data in the Work Request.
+	 */
+
 	if (hdrlen)
 		return DIV_ROUND_UP(skb->len + hdrlen, sizeof(__be64));
 
+	/* Otherwise, we're going to have to construct a Scatter gather list
+	 * of the skb body and fragments.  We also include the flits necessary
+	 * for the TX Packet Work Request and CPL.  We always have a firmware
+	 * Write Header (incorporated as part of the cpl_tx_pkt_lso and
+	 * cpl_tx_pkt structures), followed by either a TX Packet Write CPL
+	 * message or, if we're doing a Large Send Offload, an LSO CPL message
+	 * with an embedded TX Packet Write CPL message.
+	 */
 	flits = sgl_len(skb_shinfo(skb)->nr_frags + 1) + 4;
 	if (skb_shinfo(skb)->gso_size)
-		flits += 2;
+		flits += (sizeof(struct fw_eth_tx_pkt_wr) +
+			  sizeof(struct cpl_tx_pkt_lso_core) +
+			  sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64);
+	else
+		flits += (sizeof(struct fw_eth_tx_pkt_wr) +
+			  sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64);
 	return flits;
 }
 
@@ -2196,6 +2238,7 @@ static irqreturn_t t4_intr_msi(int irq, void *cookie)
 {
 	struct adapter *adap = cookie;
 
+	if (adap->flags & MASTER_PF)
 		t4_slow_intr_handler(adap);
 	process_intrq(adap);
 	return IRQ_HANDLED;
@@ -2211,7 +2254,8 @@ static irqreturn_t t4_intr_intx(int irq, void *cookie)
 	struct adapter *adap = cookie;
 
 	t4_write_reg(adap, MYPF_REG(PCIE_PF_CLI_A), 0);
-	if (t4_slow_intr_handler(adap) | process_intrq(adap))
+	if (((adap->flags & MASTER_PF) && t4_slow_intr_handler(adap)) |
+	    process_intrq(adap))
 		return IRQ_HANDLED;
 	return IRQ_NONE;             /* probably shared interrupt */
 }
@@ -2248,7 +2292,7 @@ static void sge_rx_timer_cb(unsigned long data)
 			clear_bit(id, s->starving_fl);
 			smp_mb__after_atomic();
 
-			if (fl_starving(fl)) {
+			if (fl_starving(adap, fl)) {
 				rxq = container_of(fl, struct sge_eth_rxq, fl);
 				if (napi_reschedule(&rxq->rspq.napi))
 					fl->starving++;