i40e/i40evf: Do not free the dummy packet buffer synchronously

The HW still needs to consume it and freeing it in the function
that created it would mean we will be racing with the HW. The
i40e_clean_tx_ring() routine will free up the buffer attached once
the HW has consumed it. The clean_fdir_tx_irq function had to be fixed
to handle the freeing correctly.

Cases where we program more than one filter per flow (Ipv4), the
code had to be changed to allocate dummy buffer multiple times
since it will be freed by the clean routine. This also fixes an issue
where the filter program routine was not checking if there were
descriptors available for programming a filter.

Change-ID: Idf72028fd873221934e319d021ef65a1e51acaf7
Signed-off-by: Anjali Singhai Jain <[e-mail]>
Tested-by: Jim Young <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>

drivers/net/ethernet/intel/i40e/i40e_main.c

···
 		/* clear next_to_watch to prevent false hangs */
 		tx_buf->next_to_watch = NULL;
 
+		tx_desc->buffer_addr = 0;
+		tx_desc->cmd_type_offset_bsz = 0;
+		/* move past filter desc */
+		tx_buf++;
+		tx_desc++;
+		i++;
+		if (unlikely(!i)) {
+			i -= tx_ring->count;
+			tx_buf = tx_ring->tx_bi;
+			tx_desc = I40E_TX_DESC(tx_ring, 0);
+		}
 		/* unmap skb header data */
 		dma_unmap_single(tx_ring->dev,
 				 dma_unmap_addr(tx_buf, dma),
 				 dma_unmap_len(tx_buf, len),
 				 DMA_TO_DEVICE);
+		if (tx_buf->tx_flags & I40E_TX_FLAGS_FD_SB)
+			kfree(tx_buf->raw_buf);
 
+		tx_buf->raw_buf = NULL;
+		tx_buf->tx_flags = 0;
+		tx_buf->next_to_watch = NULL;
 		dma_unmap_len_set(tx_buf, len, 0);
+		tx_desc->buffer_addr = 0;
+		tx_desc->cmd_type_offset_bsz = 0;
 
-
-		/* move to the next desc and buffer to clean */
+		/* move us past the eop_desc for start of next FD desc */
 		tx_buf++;
 		tx_desc++;
 		i++;

drivers/net/ethernet/intel/i40e/i40e_txrx.c

···
 }
 
 #define I40E_TXD_CMD (I40E_TX_DESC_CMD_EOP | I40E_TX_DESC_CMD_RS)
+#define I40E_FD_CLEAN_DELAY 10
 /**
  * i40e_program_fdir_filter - Program a Flow Director filter
  * @fdir_data: Packet data that will be filter parameters
···
 			     struct i40e_pf *pf, bool add)
 {
 	struct i40e_filter_program_desc *fdir_desc;
-	struct i40e_tx_buffer *tx_buf;
+	struct i40e_tx_buffer *tx_buf, *first;
 	struct i40e_tx_desc *tx_desc;
 	struct i40e_ring *tx_ring;
 	unsigned int fpt, dcc;
···
 	struct device *dev;
 	dma_addr_t dma;
 	u32 td_cmd = 0;
+	u16 delay = 0;
 	u16 i;
 
 	/* find existing FDIR VSI */
···
 	tx_ring = vsi->tx_rings[0];
 	dev = tx_ring->dev;
 
+	/* we need two descriptors to add/del a filter and we can wait */
+	do {
+		if (I40E_DESC_UNUSED(tx_ring) > 1)
+			break;
+		msleep_interruptible(1);
+		delay++;
+	} while (delay < I40E_FD_CLEAN_DELAY);
+
+	if (!(I40E_DESC_UNUSED(tx_ring) > 1))
+		return -EAGAIN;
+
 	dma = dma_map_single(dev, raw_packet,
 			     I40E_FDIR_MAX_RAW_PACKET_SIZE, DMA_TO_DEVICE);
 	if (dma_mapping_error(dev, dma))
···
 	/* grab the next descriptor */
 	i = tx_ring->next_to_use;
 	fdir_desc = I40E_TX_FDIRDESC(tx_ring, i);
+	first = &tx_ring->tx_bi[i];
+	memset(first, 0, sizeof(struct i40e_tx_buffer));
 
-	tx_ring->next_to_use = (i + 1 < tx_ring->count) ? i + 1 : 0;
+	tx_ring->next_to_use = ((i + 1) < tx_ring->count) ? i + 1 : 0;
 
 	fpt = (fdir_data->q_index << I40E_TXD_FLTR_QW0_QINDEX_SHIFT) &
 	      I40E_TXD_FLTR_QW0_QINDEX_MASK;
···
 	tx_desc = I40E_TX_DESC(tx_ring, i);
 	tx_buf = &tx_ring->tx_bi[i];
 
-	tx_ring->next_to_use = (i + 1 < tx_ring->count) ? i + 1 : 0;
+	tx_ring->next_to_use = ((i + 1) < tx_ring->count) ? i + 1 : 0;
+
+	memset(tx_buf, 0, sizeof(struct i40e_tx_buffer));
 
 	/* record length, and DMA address */
 	dma_unmap_len_set(tx_buf, len, I40E_FDIR_MAX_RAW_PACKET_SIZE);
···
 	tx_desc->buffer_addr = cpu_to_le64(dma);
 	td_cmd = I40E_TXD_CMD | I40E_TX_DESC_CMD_DUMMY;
 
+	tx_buf->tx_flags = I40E_TX_FLAGS_FD_SB;
+	tx_buf->raw_buf = (void *)raw_packet;
+
 	tx_desc->cmd_type_offset_bsz =
 		build_ctob(td_cmd, 0, I40E_FDIR_MAX_RAW_PACKET_SIZE, 0);
 
···
 	tx_buf->time_stamp = jiffies;
 
 	/* Force memory writes to complete before letting h/w
-	 * know there are new descriptors to fetch.  (Only
-	 * applicable for weak-ordered memory model archs,
-	 * such as IA-64).
+	 * know there are new descriptors to fetch.
 	 */
 	wmb();
 
 	/* Mark the data descriptor to be watched */
-	tx_buf->next_to_watch = tx_desc;
+	first->next_to_watch = tx_desc;
 
 	writel(tx_ring->next_to_use, tx_ring->tail);
 	return 0;
···
  * i40e_add_del_fdir_udpv4 - Add/Remove UDPv4 filters
  * @vsi: pointer to the targeted VSI
  * @fd_data: the flow director data required for the FDir descriptor
- * @raw_packet: the pre-allocated packet buffer for FDir
  * @add: true adds a filter, false removes it
  *
  * Returns 0 if the filters were successfully added or removed
  **/
 static int i40e_add_del_fdir_udpv4(struct i40e_vsi *vsi,
 				   struct i40e_fdir_filter *fd_data,
-				   u8 *raw_packet, bool add)
+				   bool add)
 {
 	struct i40e_pf *pf = vsi->back;
 	struct udphdr *udp;
 	struct iphdr *ip;
 	bool err = false;
+	u8 *raw_packet;
 	int ret;
 	static char packet[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x08, 0,
 		0x45, 0, 0, 0x1c, 0, 0, 0x40, 0, 0x40, 0x11, 0, 0, 0, 0, 0, 0,
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 
+	raw_packet = kzalloc(I40E_FDIR_MAX_RAW_PACKET_SIZE, GFP_KERNEL);
+	if (!raw_packet)
+		return -ENOMEM;
 	memcpy(raw_packet, packet, I40E_UDPIP_DUMMY_PACKET_LEN);
 
 	ip = (struct iphdr *)(raw_packet + IP_HEADER_OFFSET);
···
  * i40e_add_del_fdir_tcpv4 - Add/Remove TCPv4 filters
  * @vsi: pointer to the targeted VSI
  * @fd_data: the flow director data required for the FDir descriptor
- * @raw_packet: the pre-allocated packet buffer for FDir
  * @add: true adds a filter, false removes it
  *
  * Returns 0 if the filters were successfully added or removed
  **/
 static int i40e_add_del_fdir_tcpv4(struct i40e_vsi *vsi,
 				   struct i40e_fdir_filter *fd_data,
-				   u8 *raw_packet, bool add)
+				   bool add)
 {
 	struct i40e_pf *pf = vsi->back;
 	struct tcphdr *tcp;
 	struct iphdr *ip;
 	bool err = false;
+	u8 *raw_packet;
 	int ret;
 	/* Dummy packet */
 	static char packet[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x08, 0,
···
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x80, 0x11,
 		0x0, 0x72, 0, 0, 0, 0};
 
+	raw_packet = kzalloc(I40E_FDIR_MAX_RAW_PACKET_SIZE, GFP_KERNEL);
+	if (!raw_packet)
+		return -ENOMEM;
 	memcpy(raw_packet, packet, I40E_TCPIP_DUMMY_PACKET_LEN);
 
 	ip = (struct iphdr *)(raw_packet + IP_HEADER_OFFSET);
···
  **/
 static int i40e_add_del_fdir_sctpv4(struct i40e_vsi *vsi,
 				    struct i40e_fdir_filter *fd_data,
-				    u8 *raw_packet, bool add)
+				    bool add)
 {
 	return -EOPNOTSUPP;
 }
···
  * a specific flow spec
  * @vsi: pointer to the targeted VSI
  * @fd_data: the flow director data required for the FDir descriptor
- * @raw_packet: the pre-allocated packet buffer for FDir
  * @add: true adds a filter, false removes it
  *
  * Returns 0 if the filters were successfully added or removed
  **/
 static int i40e_add_del_fdir_ipv4(struct i40e_vsi *vsi,
 				  struct i40e_fdir_filter *fd_data,
-				  u8 *raw_packet, bool add)
+				  bool add)
 {
 	struct i40e_pf *pf = vsi->back;
 	struct iphdr *ip;
 	bool err = false;
+	u8 *raw_packet;
 	int ret;
 	int i;
 	static char packet[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x08, 0,
 		0x45, 0, 0, 0x14, 0, 0, 0x40, 0, 0x40, 0x10, 0, 0, 0, 0, 0, 0,
 		0, 0, 0, 0};
 
-	memcpy(raw_packet, packet, I40E_IP_DUMMY_PACKET_LEN);
-	ip = (struct iphdr *)(raw_packet + IP_HEADER_OFFSET);
-
-	ip->saddr = fd_data->src_ip[0];
-	ip->daddr = fd_data->dst_ip[0];
-	ip->protocol = 0;
-
 	for (i = I40E_FILTER_PCTYPE_NONF_IPV4_OTHER;
 	     i <= I40E_FILTER_PCTYPE_FRAG_IPV4;	i++) {
+		raw_packet = kzalloc(I40E_FDIR_MAX_RAW_PACKET_SIZE, GFP_KERNEL);
+		if (!raw_packet)
+			return -ENOMEM;
+		memcpy(raw_packet, packet, I40E_IP_DUMMY_PACKET_LEN);
+		ip = (struct iphdr *)(raw_packet + IP_HEADER_OFFSET);
+
+		ip->saddr = fd_data->src_ip[0];
+		ip->daddr = fd_data->dst_ip[0];
+		ip->protocol = 0;
+
 		fd_data->pctype = i;
 		ret = i40e_program_fdir_filter(fd_data, raw_packet, pf, add);
 
···
 		      struct i40e_fdir_filter *input, bool add)
 {
 	struct i40e_pf *pf = vsi->back;
-	u8 *raw_packet;
 	int ret;
-
-	/* Populate the Flow Director that we have at the moment
-	 * and allocate the raw packet buffer for the calling functions
-	 */
-	raw_packet = kzalloc(I40E_FDIR_MAX_RAW_PACKET_SIZE, GFP_KERNEL);
-	if (!raw_packet)
-		return -ENOMEM;
 
 	switch (input->flow_type & ~FLOW_EXT) {
 	case TCP_V4_FLOW:
-		ret = i40e_add_del_fdir_tcpv4(vsi, input, raw_packet,
-					      add);
+		ret = i40e_add_del_fdir_tcpv4(vsi, input, add);
 		break;
 	case UDP_V4_FLOW:
-		ret = i40e_add_del_fdir_udpv4(vsi, input, raw_packet,
-					      add);
+		ret = i40e_add_del_fdir_udpv4(vsi, input, add);
 		break;
 	case SCTP_V4_FLOW:
-		ret = i40e_add_del_fdir_sctpv4(vsi, input, raw_packet,
-					       add);
+		ret = i40e_add_del_fdir_sctpv4(vsi, input, add);
 		break;
 	case IPV4_FLOW:
-		ret = i40e_add_del_fdir_ipv4(vsi, input, raw_packet,
-					     add);
+		ret = i40e_add_del_fdir_ipv4(vsi, input, add);
 		break;
 	case IP_USER_FLOW:
 		switch (input->ip4_proto) {
 		case IPPROTO_TCP:
-			ret = i40e_add_del_fdir_tcpv4(vsi, input,
-						      raw_packet, add);
+			ret = i40e_add_del_fdir_tcpv4(vsi, input, add);
 			break;
 		case IPPROTO_UDP:
-			ret = i40e_add_del_fdir_udpv4(vsi, input,
-						      raw_packet, add);
+			ret = i40e_add_del_fdir_udpv4(vsi, input, add);
 			break;
 		case IPPROTO_SCTP:
-			ret = i40e_add_del_fdir_sctpv4(vsi, input,
-						       raw_packet, add);
+			ret = i40e_add_del_fdir_sctpv4(vsi, input, add);
 			break;
 		default:
-			ret = i40e_add_del_fdir_ipv4(vsi, input,
-						     raw_packet, add);
+			ret = i40e_add_del_fdir_ipv4(vsi, input, add);
 			break;
 		}
 		break;
···
 		ret = -EINVAL;
 	}
 
-	kfree(raw_packet);
+	/* The buffer allocated here is freed by the i40e_clean_tx_ring() */
 	return ret;
 }
 
···
 					    struct i40e_tx_buffer *tx_buffer)
 {
 	if (tx_buffer->skb) {
-		dev_kfree_skb_any(tx_buffer->skb);
+		if (tx_buffer->tx_flags & I40E_TX_FLAGS_FD_SB)
+			kfree(tx_buffer->raw_buf);
+		else
+			dev_kfree_skb_any(tx_buffer->skb);
+
 		if (dma_unmap_len(tx_buffer, len))
 			dma_unmap_single(ring->dev,
 					 dma_unmap_addr(tx_buffer, dma),

drivers/net/ethernet/intel/i40e/i40e_txrx.h

···
 #define I40E_TX_FLAGS_FCCRC		(u32)(1 << 6)
 #define I40E_TX_FLAGS_FSO		(u32)(1 << 7)
 #define I40E_TX_FLAGS_TSYN		(u32)(1 << 8)
+#define I40E_TX_FLAGS_FD_SB		(u32)(1 << 9)
 #define I40E_TX_FLAGS_VLAN_MASK		0xffff0000
 #define I40E_TX_FLAGS_VLAN_PRIO_MASK	0xe0000000
 #define I40E_TX_FLAGS_VLAN_PRIO_SHIFT	29
···
 struct i40e_tx_buffer {
 	struct i40e_tx_desc *next_to_watch;
 	unsigned long time_stamp;
-	struct sk_buff *skb;
+	union {
+		struct sk_buff *skb;
+		void *raw_buf;
+	};
 	unsigned int bytecount;
 	unsigned short gso_segs;
 	DEFINE_DMA_UNMAP_ADDR(dma);

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

···
 					    struct i40e_tx_buffer *tx_buffer)
 {
 	if (tx_buffer->skb) {
-		dev_kfree_skb_any(tx_buffer->skb);
+		if (tx_buffer->tx_flags & I40E_TX_FLAGS_FD_SB)
+			kfree(tx_buffer->raw_buf);
+		else
+			dev_kfree_skb_any(tx_buffer->skb);
+
 		if (dma_unmap_len(tx_buffer, len))
 			dma_unmap_single(ring->dev,
 					 dma_unmap_addr(tx_buffer, dma),

drivers/net/ethernet/intel/i40evf/i40e_txrx.h

···
 #define I40E_TX_FLAGS_IPV6		(u32)(1 << 5)
 #define I40E_TX_FLAGS_FCCRC		(u32)(1 << 6)
 #define I40E_TX_FLAGS_FSO		(u32)(1 << 7)
+#define I40E_TX_FLAGS_FD_SB		(u32)(1 << 9)
 #define I40E_TX_FLAGS_VLAN_MASK		0xffff0000
 #define I40E_TX_FLAGS_VLAN_PRIO_MASK	0xe0000000
 #define I40E_TX_FLAGS_VLAN_PRIO_SHIFT	29
···
 struct i40e_tx_buffer {
 	struct i40e_tx_desc *next_to_watch;
 	unsigned long time_stamp;
-	struct sk_buff *skb;
+	union {
+		struct sk_buff *skb;
+		void *raw_buf;
+	};
 	unsigned int bytecount;
 	unsigned short gso_segs;
 	DEFINE_DMA_UNMAP_ADDR(dma);