Merge branch 'nfp-fix-ethtool-stats-and-page-allocation'

Jakub Kicinski says:

====================
nfp: fix ethtool stats and page allocation

Two fixes for net.  First one makes sure we handle gather of stats on
32bit machines correctly (ouch).  The second fix solves a potential
NULL-deref if we fail to allocate a page with XDP running.

I used Fixes: tags pointing to where the bug was introduced, but for
patch 1 it has been in the driver "for ever" and fix won't backport
cleanly beyond commit 325945ed ("nfp: split software and hardware
vNIC statistics") which is in net.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -1180,10 +1180,14 @@ static void *nfp_net_rx_alloc_one(struct nfp_net_dp *dp, dma_addr_t *dma_addr)
 {
 	void *frag;
 
-	if (!dp->xdp_prog)
+	if (!dp->xdp_prog) {
 		frag = netdev_alloc_frag(dp->fl_bufsz);
-	else
-		frag = page_address(alloc_page(GFP_KERNEL | __GFP_COLD));
+	} else {
+		struct page *page;
+
+		page = alloc_page(GFP_KERNEL | __GFP_COLD);
+		frag = page ? page_address(page) : NULL;
+	}
 	if (!frag) {
 		nn_dp_warn(dp, "Failed to alloc receive page frag\n");
 		return NULL;
@@ -1203,10 +1207,14 @@ static void *nfp_net_napi_alloc_one(struct nfp_net_dp *dp, dma_addr_t *dma_addr)
 {
 	void *frag;
 
-	if (!dp->xdp_prog)
+	if (!dp->xdp_prog) {
 		frag = napi_alloc_frag(dp->fl_bufsz);
-	else
-		frag = page_address(alloc_page(GFP_ATOMIC | __GFP_COLD));
+	} else {
+		struct page *page;
+
+		page = alloc_page(GFP_ATOMIC | __GFP_COLD);
+		frag = page ? page_address(page) : NULL;
+	}
 	if (!frag) {
 		nn_dp_warn(dp, "Failed to alloc receive page frag\n");
 		return NULL;

drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c

@@ -464,7 +464,7 @@ static u64 *nfp_vnic_get_sw_stats(struct net_device *netdev, u64 *data)
 
 		do {
 			start = u64_stats_fetch_begin(&nn->r_vecs[i].rx_sync);
-			*data++ = nn->r_vecs[i].rx_pkts;
+			data[0] = nn->r_vecs[i].rx_pkts;
 			tmp[0] = nn->r_vecs[i].hw_csum_rx_ok;
 			tmp[1] = nn->r_vecs[i].hw_csum_rx_inner_ok;
 			tmp[2] = nn->r_vecs[i].hw_csum_rx_error;
@@ -472,14 +472,16 @@ static u64 *nfp_vnic_get_sw_stats(struct net_device *netdev, u64 *data)
 
 		do {
 			start = u64_stats_fetch_begin(&nn->r_vecs[i].tx_sync);
-			*data++ = nn->r_vecs[i].tx_pkts;
-			*data++ = nn->r_vecs[i].tx_busy;
+			data[1] = nn->r_vecs[i].tx_pkts;
+			data[2] = nn->r_vecs[i].tx_busy;
 			tmp[3] = nn->r_vecs[i].hw_csum_tx;
 			tmp[4] = nn->r_vecs[i].hw_csum_tx_inner;
 			tmp[5] = nn->r_vecs[i].tx_gather;
 			tmp[6] = nn->r_vecs[i].tx_lso;
 		} while (u64_stats_fetch_retry(&nn->r_vecs[i].tx_sync, start));
 
+		data += 3;
+
 		for (j = 0; j < NN_ET_RVEC_GATHER_STATS; j++)
 			gathered_stats[j] += tmp[j];
 	}