netxen: 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/netxen/netxen_nic.h

···
 
 #define	MAX_NUM_CARDS		4
 
-#define MAX_BUFFERS_PER_CMD	32
+#define NETXEN_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 \
···
  */
 struct netxen_cmd_buffer {
 	struct sk_buff *skb;
-	struct netxen_skb_frag frag_array[MAX_BUFFERS_PER_CMD + 1];
+	struct netxen_skb_frag frag_array[MAX_SKB_FRAGS + 1];
 	u32 frag_count;
 };
 

drivers/net/netxen/netxen_nic_main.c

···
 	struct cmd_desc_type0 *hwdesc, *first_desc;
 	struct pci_dev *pdev;
 	int i, k;
+	int delta = 0;
+	struct skb_frag_struct *frag;
 
 	u32 producer;
 	int frag_count, no_of_desc;
···
 
 	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 > NETXEN_MAX_FRAGS_PER_TX) {
+
+		for (i = 0; i < (frag_count - NETXEN_MAX_FRAGS_PER_TX); i++) {
+			frag = &skb_shinfo(skb)->frags[i];
+			delta += frag->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;