firewire: net: ratelimit error messages

Unfortunately its easy to trigger such error messages by removing the
cable while sending streams of data over the link.

Such errors are normal, and therefore this patch stops firewire-net from
flooding the kernel log with these errors, by combining series of same
errors together.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>

(Stefan R:)  Eventually we should remove this logging when firewire-net
and related firewire-ohci facilities have been stabilized.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/net.c

@@ -996,15 +996,23 @@ static void fwnet_transmit_packet_failed(struct fwnet_packet_task *ptask)
 static void fwnet_write_complete(struct fw_card *card, int rcode,
 				 void *payload, size_t length, void *data)
 {
-	struct fwnet_packet_task *ptask;
-
-	ptask = data;
+	struct fwnet_packet_task *ptask = data;
+	static unsigned long j;
+	static int last_rcode, errors_skipped;
 
 	if (rcode == RCODE_COMPLETE) {
 		fwnet_transmit_packet_done(ptask);
 	} else {
-		fw_error("fwnet_write_complete: failed: %x\n", rcode);
 		fwnet_transmit_packet_failed(ptask);
+
+		if (printk_timed_ratelimit(&j,  1000) || rcode != last_rcode) {
+			fw_error("fwnet_write_complete: "
+				"failed: %x (skipped %d)\n", rcode, errors_skipped);
+
+			errors_skipped = 0;
+			last_rcode = rcode;
+		} else
+			errors_skipped++;
 	}
 }