xen-netback: create a debugfs node for hash information

It is useful to be able to see the hash configuration when running tests.
This patch adds a debugfs node for that purpose.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
index fb87cb3..282b16d 100644
--- a/drivers/net/xen-netback/hash.c
+++ b/drivers/net/xen-netback/hash.c
@@ -369,6 +369,74 @@
 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
 }
 
+#ifdef CONFIG_DEBUG_FS
+void xenvif_dump_hash_info(struct xenvif *vif, struct seq_file *m)
+{
+	unsigned int i;
+
+	switch (vif->hash.alg) {
+	case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:
+		seq_puts(m, "Hash Algorithm: TOEPLITZ\n");
+		break;
+
+	case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:
+		seq_puts(m, "Hash Algorithm: NONE\n");
+		/* FALLTHRU */
+	default:
+		return;
+	}
+
+	if (vif->hash.flags) {
+		seq_puts(m, "\nHash Flags:\n");
+
+		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4)
+			seq_puts(m, "- IPv4\n");
+		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)
+			seq_puts(m, "- IPv4 + TCP\n");
+		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6)
+			seq_puts(m, "- IPv6\n");
+		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)
+			seq_puts(m, "- IPv6 + TCP\n");
+	}
+
+	seq_puts(m, "\nHash Key:\n");
+
+	for (i = 0; i < XEN_NETBK_MAX_HASH_KEY_SIZE; ) {
+		unsigned int j, n;
+
+		n = 8;
+		if (i + n >= XEN_NETBK_MAX_HASH_KEY_SIZE)
+			n = XEN_NETBK_MAX_HASH_KEY_SIZE - i;
+
+		seq_printf(m, "[%2u - %2u]: ", i, i + n - 1);
+
+		for (j = 0; j < n; j++, i++)
+			seq_printf(m, "%02x ", vif->hash.key[i]);
+
+		seq_puts(m, "\n");
+	}
+
+	if (vif->hash.size != 0) {
+		seq_puts(m, "\nHash Mapping:\n");
+
+		for (i = 0; i < vif->hash.size; ) {
+			unsigned int j, n;
+
+			n = 8;
+			if (i + n >= vif->hash.size)
+				n = vif->hash.size - i;
+
+			seq_printf(m, "[%4u - %4u]: ", i, i + n - 1);
+
+			for (j = 0; j < n; j++, i++)
+				seq_printf(m, "%4u ", vif->hash.mapping[i]);
+
+			seq_puts(m, "\n");
+		}
+	}
+}
+#endif /* CONFIG_DEBUG_FS */
+
 void xenvif_init_hash(struct xenvif *vif)
 {
 	if (xenvif_hash_cache_size == 0)