qlcnic: limit skb frags for non tso packet

Machines are getting deadlock in four node cluster environment.
All nodes are accessing (find /gfs2 -depth -print|cpio -ocv > /dev/null)
200 GB storage on a GFS2 filesystem.
This result in memory fragmentation and driver receives 18 frags for
1448 byte packets.
For non tso packet, fw drops the tx request, if it has >14 frags.

Fixing it by pulling extra frags.

Cc: [e-mail]
Signed-off-by: Amit Kumar Salecha <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/qlcnic/qlcnic.h

···
 #define TX_UDPV6_PKT	0x0c
 
 /* Tx defines */
+#define QLCNIC_MAX_FRAGS_PER_TX	14
 #define MAX_TSO_HEADER_DESC	2
 #define MGMT_CMD_DESC_RESV	4
 #define TX_STOP_THRESH		((MAX_SKB_FRAGS >> 2) + MAX_TSO_HEADER_DESC \

drivers/net/qlcnic/qlcnic_main.c

···
 	struct cmd_desc_type0 *hwdesc, *first_desc;
 	struct pci_dev *pdev;
 	struct ethhdr *phdr;
+	int delta = 0;
 	int i, k;
 
 	u32 producer;
···
 	}
 
 	frag_count = skb_shinfo(skb)->nr_frags + 1;
+	/* 14 frags supported for normal packet and
+	 * 32 frags supported for TSO packet
+	 */
+	if (!skb_is_gso(skb) && frag_count > QLCNIC_MAX_FRAGS_PER_TX) {
+
+		for (i = 0; i < (frag_count - QLCNIC_MAX_FRAGS_PER_TX); i++)
+			delta += skb_shinfo(skb)->frags[i].size;
+
+		if (!__pskb_pull_tail(skb, delta))
+			goto drop_packet;
+
+		frag_count = 1 + skb_shinfo(skb)->nr_frags;
+	}
 
 	/* 4 fragments per cmd des */
 	no_of_desc = (frag_count + 3) >> 2;