sfc: Implement adaptive IRQ moderation

Calculate a score for each 1000 IRQs:
- TX completions are worth 1 point
- RX completions are worth 4 if merged using LRO or 2 otherwise

Reduce moderation if the score is less than 10000, down to a minimum
of 5 us.  Increase moderation if the score is more than 20000, up to
the specified maximum.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/efx.h b/drivers/net/sfc/efx.h
index 8bde1d2..da157aa 100644
--- a/drivers/net/sfc/efx.h
+++ b/drivers/net/sfc/efx.h
@@ -52,7 +52,7 @@
 extern void efx_suspend(struct efx_nic *efx);
 extern void efx_resume(struct efx_nic *efx);
 extern void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs,
-				    int rx_usecs);
+				    int rx_usecs, bool rx_adaptive);
 extern int efx_request_power(struct efx_nic *efx, int mw, const char *name);
 extern void efx_hex_dump(const u8 *, unsigned int, const char *);