myri10ge: allow small_bytes = 0

Allow page-based receive to work when small_bytes is set to 0.
Signed-off-by: Jon Mason <mason@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/myri10ge/myri10ge.c

@@ -2004,8 +2004,12 @@ static int myri10ge_allocate_rings(struct myri10ge_slice_state *ss)
 	ss->rx_big.page_offset = MYRI10GE_ALLOC_SIZE;
 	ss->rx_small.watchdog_needed = 0;
 	ss->rx_big.watchdog_needed = 0;
-	myri10ge_alloc_rx_pages(mgp, &ss->rx_small,
-				mgp->small_bytes + MXGEFW_PAD, 0);
+	if (mgp->small_bytes == 0) {
+		ss->rx_small.fill_cnt = ss->rx_small.mask + 1;
+	} else {
+		myri10ge_alloc_rx_pages(mgp, &ss->rx_small,
+					mgp->small_bytes + MXGEFW_PAD, 0);
+	}
 
 	if (ss->rx_small.fill_cnt < ss->rx_small.mask + 1) {
 		netdev_err(dev, "slice-%d: alloced only %d small bufs\n",
@@ -2031,6 +2035,8 @@ static int myri10ge_allocate_rings(struct myri10ge_slice_state *ss)
 	}
 
 abort_with_rx_small_ring:
+	if (mgp->small_bytes == 0)
+		ss->rx_small.fill_cnt = ss->rx_small.cnt;
 	for (i = ss->rx_small.cnt; i < ss->rx_small.fill_cnt; i++) {
 		int idx = i & ss->rx_small.mask;
 		myri10ge_unmap_rx_page(mgp->pdev, &ss->rx_small.info[idx],
@@ -2081,6 +2087,8 @@ static void myri10ge_free_rings(struct myri10ge_slice_state *ss)
 		put_page(ss->rx_big.info[idx].page);
 	}
 
+	if (mgp->small_bytes == 0)
+		ss->rx_small.fill_cnt = ss->rx_small.cnt;
 	for (i = ss->rx_small.cnt; i < ss->rx_small.fill_cnt; i++) {
 		idx = i & ss->rx_small.mask;
 		if (i == ss->rx_small.fill_cnt - 1)
@@ -2418,7 +2426,7 @@ static int myri10ge_open(struct net_device *dev)
 		mgp->small_bytes = VLAN_ETH_FRAME_LEN;
 
 	/* Override the small buffer size? */
-	if (myri10ge_small_bytes > 0)
+	if (myri10ge_small_bytes >= 0)
 		mgp->small_bytes = myri10ge_small_bytes;
 
 	/* Firmware needs the big buff size as a power of 2.  Lie and