simplify the code to initialize the RDT while in netmap mode.

2 files changed, 9 insertions, 20 deletions

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index eedc0fa..b210d4e 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -4333,6 +4333,8 @@ em_initialize_receive_unit(struct adapter *adapter)
 
 	for (int i = 0; i < adapter->num_queues; i++, rxr++) {
 		/* Setup the Base and Length of the Rx Descriptor Ring */
+		u32 rdt = adapter->num_rx_desc - 1; /* default */
+
 		bus_addr = rxr->rxdma.dma_paddr;
 		E1000_WRITE_REG(hw, E1000_RDLEN(i),
 		    adapter->num_rx_desc * sizeof(struct e1000_rx_desc));
@@ -4344,18 +4346,11 @@ em_initialize_receive_unit(struct adapter *adapter)
 		/*
 		 * an init() while a netmap client is active must
 		 * preserve the rx buffers passed to userspace.
-		 * In this driver it means we adjust RDT to
-		 * something different from na->num_rx_desc - 1.
 		 */
-		if (ifp->if_capenable & IFCAP_NETMAP) {
-			struct netmap_adapter *na = NA(adapter->ifp);
-			struct netmap_kring *kring = &na->rx_rings[i];
-			int t = na->num_rx_desc - 1 - kring->nr_hwavail;
-
-			E1000_WRITE_REG(hw, E1000_RDT(i), t);
-		} else
+		if (ifp->if_capenable & IFCAP_NETMAP)
+			rdt -= NA(adapter->ifp)->rx_rings[i].nr_hwavail;
 #endif /* DEV_NETMAP */
-		E1000_WRITE_REG(hw, E1000_RDT(i), adapter->num_rx_desc - 1);
+		E1000_WRITE_REG(hw, E1000_RDT(i), rdt);
 	}
 
 	/* Set PTHRESH for improved jumbo performance */
diff --git a/sys/dev/e1000/if_lem.c b/sys/dev/e1000/if_lem.c
index ae7893a..0ecf651 100644
--- a/sys/dev/e1000/if_lem.c
+++ b/sys/dev/e1000/if_lem.c
@@ -3361,19 +3361,13 @@ lem_initialize_receive_unit(struct adapter *adapter)
 	 * Tail Descriptor Pointers
 	 */
 	E1000_WRITE_REG(&adapter->hw, E1000_RDH(0), 0);
+	rctl = adapter->num_rx_desc - 1; /* default RDT value */
 #ifdef DEV_NETMAP
 	/* preserve buffers already made available to clients */
-	if (ifp->if_capenable & IFCAP_NETMAP) {
-		struct netmap_adapter *na = NA(adapter->ifp);
-		struct netmap_kring *kring = &na->rx_rings[0];
-		int t = na->num_rx_desc - 1 - kring->nr_hwavail;
-
-		if (t >= na->num_rx_desc)
-			t -= na->num_rx_desc;
-		E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), t);
-	} else
+	if (ifp->if_capenable & IFCAP_NETMAP)
+		rctl -= NA(adapter->ifp)->rx_rings[0].nr_hwavail;
 #endif /* DEV_NETMAP */
-	E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), adapter->num_rx_desc - 1);
+	E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), rctl);
 
 	return;
 }