bnx2x: add support for low latency rx

index f76597e..edda716 100644
@@ -485,6 +485,21 @@ struct bnx2x_fastpath {
 	struct bnx2x		*bp; /* parent */
 
 	struct napi_struct	napi;
+
+#ifdef CONFIG_NET_LL_RX_POLL
+	unsigned int state;
+#define BNX2X_FP_STATE_IDLE		      0
+#define BNX2X_FP_STATE_NAPI		(1 << 0)    /* NAPI owns this FP */
+#define BNX2X_FP_STATE_POLL		(1 << 1)    /* poll owns this FP */
+#define BNX2X_FP_STATE_NAPI_YIELD	(1 << 2)    /* NAPI yielded this FP */
+#define BNX2X_FP_STATE_POLL_YIELD	(1 << 3)    /* poll yielded this FP */
+#define BNX2X_FP_YIELD	(BNX2X_FP_STATE_NAPI_YIELD | BNX2X_FP_STATE_POLL_YIELD)
+#define BNX2X_FP_LOCKED	(BNX2X_FP_STATE_NAPI | BNX2X_FP_STATE_POLL)
+#define BNX2X_FP_USER_PEND (BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_POLL_YIELD)
+	/* protect state */
+	spinlock_t lock;
+#endif /* CONFIG_NET_LL_RX_POLL */
+
 	union host_hc_status_block	status_blk;
 	/* chip independent shortcuts into sb structure */
 	__le16			*sb_index_values;

@@ -557,6 +572,116 @@ struct bnx2x_fastpath {
 #define bnx2x_fp_stats(bp, fp)	(&((bp)->fp_stats[(fp)->index]))
 #define bnx2x_fp_qstats(bp, fp)	(&((bp)->fp_stats[(fp)->index].eth_q_stats))
 
+#ifdef CONFIG_NET_LL_RX_POLL
+static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp)
+{
+	spin_lock_init(&fp->lock);
+	fp->state = BNX2X_FP_STATE_IDLE;
+}
+
+/* called from the device poll routine to get ownership of a FP */
+static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp)
+{
+	bool rc = true;
+
+	spin_lock(&fp->lock);
+	if (fp->state & BNX2X_FP_LOCKED) {
+		WARN_ON(fp->state & BNX2X_FP_STATE_NAPI);
+		fp->state |= BNX2X_FP_STATE_NAPI_YIELD;
+		rc = false;
+	} else {
+		/* we don't care if someone yielded */
+		fp->state = BNX2X_FP_STATE_NAPI;
+	}
+	spin_unlock(&fp->lock);
+	return rc;
+}
+
+/* returns true is someone tried to get the FP while napi had it */
+static inline bool bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
+{
+	bool rc = false;
+
+	spin_lock(&fp->lock);
+	WARN_ON(fp->state &
+		(BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_NAPI_YIELD));
+
+	if (fp->state & BNX2X_FP_STATE_POLL_YIELD)
+		rc = true;
+	fp->state = BNX2X_FP_STATE_IDLE;
+	spin_unlock(&fp->lock);
+	return rc;
+}
+
+/* called from bnx2x_low_latency_poll() */
+static inline bool bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp)
+{
+	bool rc = true;
+
+	spin_lock_bh(&fp->lock);
+	if ((fp->state & BNX2X_FP_LOCKED)) {
+		fp->state |= BNX2X_FP_STATE_POLL_YIELD;
+		rc = false;
+	} else {
+		/* preserve yield marks */
+		fp->state |= BNX2X_FP_STATE_POLL;
+	}
+	spin_unlock_bh(&fp->lock);
+	return rc;
+}
+
+/* returns true if someone tried to get the FP while it was locked */
+static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
+{
+	bool rc = false;
+
+	spin_lock_bh(&fp->lock);
+	WARN_ON(fp->state & BNX2X_FP_STATE_NAPI);
+
+	if (fp->state & BNX2X_FP_STATE_POLL_YIELD)
+		rc = true;
+	fp->state = BNX2X_FP_STATE_IDLE;
+	spin_unlock_bh(&fp->lock);
+	return rc;
+}
+
+/* true if a socket is polling, even if it did not get the lock */
+static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp)
+{
+	WARN_ON(!(fp->state & BNX2X_FP_LOCKED));
+	return fp->state & BNX2X_FP_USER_PEND;
+}
+#else
+static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp)
+{
+}
+
+static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp)
+{
+	return true;
+}
+
+static inline bool bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
+{
+	return false;
+}
+
+static inline bool bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp)
+{
+	return false;
+}
+
+static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
+{
+	return false;
+}
+
+static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp)
+{
+	return false;
+}
+#endif /* CONFIG_NET_LL_RX_POLL */
+
 /* Use 2500 as a mini-jumbo MTU for FCoE */
 #define BNX2X_FCOE_MINI_JUMBO_MTU	2500
 

130 lines not on this page · raw message

index 650bb52..a1a5cdc 100644
@@ -605,6 +605,13 @@ int bnx2x_enable_msi(struct bnx2x *bp);
 int bnx2x_poll(struct napi_struct *napi, int budget);
 
 /**
+ * bnx2x_low_latency_recv - LL callback
+ *
+ * @napi:	napi structure
+ */
+int bnx2x_low_latency_recv(struct napi_struct *napi);
+
+/**
  * bnx2x_alloc_mem_bp - allocate memories outsize main driver structure
  *
  * @bp:		driver handle

@@ -846,9 +853,11 @@ static inline void bnx2x_add_all_napi_cnic(struct bnx2x *bp)
 	int i;
 
 	/* Add NAPI objects */
-	for_each_rx_queue_cnic(bp, i)
+	for_each_rx_queue_cnic(bp, i) {
 		netif_napi_add(bp->dev, &bnx2x_fp(bp, i, napi),
 			       bnx2x_poll, NAPI_POLL_WEIGHT);
+		napi_hash_add(&bnx2x_fp(bp, i, napi));
+	}
 }
 
 static inline void bnx2x_add_all_napi(struct bnx2x *bp)

@@ -856,25 +865,31 @@ static inline void bnx2x_add_all_napi(struct bnx2x *bp)
 	int i;
 
 	/* Add NAPI objects */
-	for_each_eth_queue(bp, i)
+	for_each_eth_queue(bp, i) {
 		netif_napi_add(bp->dev, &bnx2x_fp(bp, i, napi),
 			       bnx2x_poll, NAPI_POLL_WEIGHT);
+		napi_hash_add(&bnx2x_fp(bp, i, napi));
+	}
 }
 
 static inline void bnx2x_del_all_napi_cnic(struct bnx2x *bp)
 {
 	int i;
 
-	for_each_rx_queue_cnic(bp, i)
+	for_each_rx_queue_cnic(bp, i) {
+		napi_hash_del(&bnx2x_fp(bp, i, napi));
 		netif_napi_del(&bnx2x_fp(bp, i, napi));
+	}
 }
 
 static inline void bnx2x_del_all_napi(struct bnx2x *bp)
 {
 	int i;
 
-	for_each_eth_queue(bp, i)
+	for_each_eth_queue(bp, i) {
+		napi_hash_del(&bnx2x_fp(bp, i, napi));
 		netif_napi_del(&bnx2x_fp(bp, i, napi));
+	}
 }
 
 int bnx2x_set_int_mode(struct bnx2x *bp);

index 658b9fd..e2e8705 100644
@@ -12013,6 +12013,10 @@ static const struct net_device_ops bnx2x_netdev_ops = {
 #ifdef NETDEV_FCOE_WWNN
 	.ndo_fcoe_get_wwn	= bnx2x_fcoe_get_wwn,
 #endif
+
+#ifdef CONFIG_NET_LL_RX_POLL
+	.ndo_ll_poll		= bnx2x_low_latency_recv,
+#endif
 };
 
 static int bnx2x_set_coherency_mask(struct bnx2x *bp)

index 20eefa6..ca7f2bb 100644
@@ -804,40 +804,32 @@ int bnx2x_rx_int(struct bnx2x_fastpath *fp, int budget)
 {
 	struct bnx2x *bp = fp->bp;
 	u16 bd_cons, bd_prod, bd_prod_fw, comp_ring_cons;
-	u16 hw_comp_cons, sw_comp_cons, sw_comp_prod;
+	u16 sw_comp_cons, sw_comp_prod;
 	int rx_pkt = 0;
+	union eth_rx_cqe *cqe;
+	struct eth_fast_path_rx_cqe *cqe_fp;
 
 #ifdef BNX2X_STOP_ON_ERROR
 	if (unlikely(bp->panic))
 		return 0;
 #endif
 
-	/* CQ "next element" is of the size of the regular element,
-	   that's why it's ok here */
-	hw_comp_cons = le16_to_cpu(*fp->rx_cons_sb);
-	if ((hw_comp_cons & MAX_RCQ_DESC_CNT) == MAX_RCQ_DESC_CNT)
-		hw_comp_cons++;
-
 	bd_cons = fp->rx_bd_cons;
 	bd_prod = fp->rx_bd_prod;
 	bd_prod_fw = bd_prod;
 	sw_comp_cons = fp->rx_comp_cons;
 	sw_comp_prod = fp->rx_comp_prod;
 
-	/* Memory barrier necessary as speculative reads of the rx
-	 * buffer can be ahead of the index in the status block
-	 */
-	rmb();
+	comp_ring_cons = RCQ_BD(sw_comp_cons);
+	cqe = &fp->rx_comp_ring[comp_ring_cons];
+	cqe_fp = &cqe->fast_path_cqe;
 
 	DP(NETIF_MSG_RX_STATUS,
-	   "queue[%d]:  hw_comp_cons %u  sw_comp_cons %u\n",
-	   fp->index, hw_comp_cons, sw_comp_cons);
+	   "queue[%d]: sw_comp_cons %u\n", fp->index, sw_comp_cons);
 
-	while (sw_comp_cons != hw_comp_cons) {
+	while (BNX2X_IS_CQE_COMPLETED(cqe_fp)) {
 		struct sw_rx_bd *rx_buf = NULL;
 		struct sk_buff *skb;
-		union eth_rx_cqe *cqe;
-		struct eth_fast_path_rx_cqe *cqe_fp;
 		u8 cqe_fp_flags;
 		enum eth_rx_cqe_type cqe_fp_type;
 		u16 len, pad, queue;

@@ -849,12 +841,9 @@ int bnx2x_rx_int(struct bnx2x_fastpath *fp, int budget)
 			return 0;
 #endif
 
-		comp_ring_cons = RCQ_BD(sw_comp_cons);
 		bd_prod = RX_BD(bd_prod);
 		bd_cons = RX_BD(bd_cons);
 
-		cqe = &fp->rx_comp_ring[comp_ring_cons];
-		cqe_fp = &cqe->fast_path_cqe;
 		cqe_fp_flags = cqe_fp->type_error_flags;
 		cqe_fp_type = cqe_fp_flags & ETH_FAST_PATH_RX_CQE_TYPE;
 

@@ -1018,8 +1007,15 @@ next_cqe:
 		sw_comp_prod = NEXT_RCQ_IDX(sw_comp_prod);
 		sw_comp_cons = NEXT_RCQ_IDX(sw_comp_cons);
 
+		/* mark CQE as free */
+		BNX2X_SEED_CQE(cqe_fp);
+
 		if (rx_pkt == budget)
 			break;
+
+		comp_ring_cons = RCQ_BD(sw_comp_cons);
+		cqe = &fp->rx_comp_ring[comp_ring_cons];
+		cqe_fp = &cqe->fast_path_cqe;
 	} /* while */
 
 	fp->rx_bd_cons = bd_cons;

@@ -1055,8 +1051,6 @@ static irqreturn_t bnx2x_msix_fp_int(int irq, void *fp_cookie)
 #endif
 
 	/* Handle Rx and Tx according to MSI-X vector */
-	prefetch(fp->rx_cons_sb);
-
 	for_each_cos_in_tx_queue(fp, cos)
 		prefetch(fp->txdata_ptr[cos]->tx_cons_sb);
 

@@ -3137,10 +3131,8 @@ int bnx2x_low_latency_recv(struct napi_struct *napi)
 	if (!bnx2x_fp_lock_poll(fp))
 		return LL_FLUSH_BUSY;
 
-	if (bnx2x_has_rx_work(fp)) {
-		bnx2x_update_fpsb_idx(fp);
+	if (bnx2x_has_rx_work(fp))
 		found = bnx2x_rx_int(fp, 4);
-	}
 
 	bnx2x_fp_unlock_poll(fp);
 

@@ -4339,10 +4331,11 @@ static int bnx2x_alloc_fp_mem_at(struct bnx2x *bp, int index)
 				&bnx2x_fp(bp, index, rx_desc_mapping),
 				sizeof(struct eth_rx_bd) * NUM_RX_BD);
 
-		BNX2X_PCI_ALLOC(bnx2x_fp(bp, index, rx_comp_ring),
-				&bnx2x_fp(bp, index, rx_comp_mapping),
-				sizeof(struct eth_fast_path_rx_cqe) *
-				NUM_RCQ_BD);
+		/* Seed all CQEs by 1s */
+		BNX2X_PCI_FALLOC(bnx2x_fp(bp, index, rx_comp_ring),
+				 &bnx2x_fp(bp, index, rx_comp_mapping),
+				 sizeof(struct eth_fast_path_rx_cqe) *
+				 NUM_RCQ_BD);
 
 		/* SGE ring */
 		BNX2X_ALLOC(bnx2x_fp(bp, index, rx_page_ring),

index a1a5cdc..c07a6d0 100644
@@ -59,6 +59,16 @@ extern int int_mode;
 		   (unsigned long long)(*y), x); \
 	} while (0)
 
+#define BNX2X_PCI_FALLOC(x, y, size) \
+	do { \
+		x = dma_alloc_coherent(&bp->pdev->dev, size, y, GFP_KERNEL); \
+		if (x == NULL) \
+			goto alloc_mem_err; \
+		memset((void *)x, 0xFFFFFFFF, size); \
+		DP(NETIF_MSG_HW, "BNX2X_PCI_FALLOC: Physical %Lx Virtual %p\n",\
+		   (unsigned long long)(*y), x); \
+	} while (0)
+
 #define BNX2X_ALLOC(x, size) \
 	do { \
 		x = kzalloc(size, GFP_KERNEL); \

@@ -805,16 +815,18 @@ static inline bool bnx2x_has_tx_work(struct bnx2x_fastpath *fp)
 	return false;
 }
 
+#define BNX2X_IS_CQE_COMPLETED(cqe_fp) (cqe_fp->marker == 0x0)
+#define BNX2X_SEED_CQE(cqe_fp) (cqe_fp->marker = 0xFFFFFFFF)
 static inline int bnx2x_has_rx_work(struct bnx2x_fastpath *fp)
 {
-	u16 rx_cons_sb;
+	u16 cons;
+	union eth_rx_cqe *cqe;
+	struct eth_fast_path_rx_cqe *cqe_fp;
 
-	/* Tell compiler that status block fields can change */
-	barrier();
-	rx_cons_sb = le16_to_cpu(*fp->rx_cons_sb);
-	if ((rx_cons_sb & MAX_RCQ_DESC_CNT) == MAX_RCQ_DESC_CNT)
-		rx_cons_sb++;
-	return (fp->rx_comp_cons != rx_cons_sb);
+	cons = RCQ_BD(fp->rx_comp_cons);
+	cqe = &fp->rx_comp_ring[cons];
+	cqe_fp = &cqe->fast_path_cqe;
+	return BNX2X_IS_CQE_COMPLETED(cqe_fp);
 }
 
 /**

index 5ef3f96..5018e52 100644
@@ -3818,7 +3818,8 @@ struct eth_fast_path_rx_cqe {
 	__le16 len_on_bd;
 	struct parsing_flags pars_flags;
 	union eth_sgl_or_raw_data sgl_or_raw_data;
-	__le32 reserved1[8];
+	__le32 reserved1[7];
+	u32 marker;
 };
 
 

index e2e8705..f0d21fa 100644
@@ -1866,7 +1866,6 @@ irqreturn_t bnx2x_interrupt(int irq, void *dev_instance)
 		mask = 0x2 << (fp->index + CNIC_SUPPORT(bp));
 		if (status & mask) {
 			/* Handle Rx or Tx according to SB id */
-			prefetch(fp->rx_cons_sb);
 			for_each_cos_in_tx_queue(fp, cos)
 				prefetch(fp->txdata_ptr[cos]->tx_cons_sb);
 			prefetch(&fp->sb_running_index[SM_RX_ID]);