svn commit: r363378 - head/sys/net

[Vincenzo Maffione]

Author: vmaffione
Date: Mon Jul 20 21:08:56 2020
New Revision: 363378
URL: https://svnweb.freebsd.org/changeset/base/363378

Log:
  iflib: initialize netmap with the correct number of descriptors
  
  In case the network device has a RX or TX control queue, the correct
  number of TX/RX descriptors is contained in the second entry of the
  isc_ntxd (or isc_nrxd) array, rather than in the first entry.
  This case is correctly handled by iflib_device_register() and
  iflib_pseudo_register(), but not by iflib_netmap_attach().
  If the first entry is larger than the second, this can result in a
  panic. This change fixes the bug by introducing two helper functions
  that also lead to some code simplification.
  
  PR:	247647
  MFC after:	3 weeks
  Differential Revision:	https://reviews.freebsd.org/D25541

Modified:
  head/sys/net/iflib.c

Modified: head/sys/net/iflib.c
==============================================================================
--- head/sys/net/iflib.c	Mon Jul 20 20:36:32 2020	(r363377)
+++ head/sys/net/iflib.c	Mon Jul 20 21:08:56 2020	(r363378)
@@ -730,6 +730,26 @@ MTX_SYSINIT(iflib_cpu_offset, &cpu_offset_mtx, "iflib_
 
 DEBUGNET_DEFINE(iflib);
 
+static int
+iflib_num_rx_descs(if_ctx_t ctx)
+{
+	if_softc_ctx_t scctx = &ctx->ifc_softc_ctx;
+	if_shared_ctx_t sctx = ctx->ifc_sctx;
+	uint16_t first_rxq = (sctx->isc_flags & IFLIB_HAS_RXCQ) ? 1 : 0;
+
+	return scctx->isc_nrxd[first_rxq];
+}
+
+static int
+iflib_num_tx_descs(if_ctx_t ctx)
+{
+	if_softc_ctx_t scctx = &ctx->ifc_softc_ctx;
+	if_shared_ctx_t sctx = ctx->ifc_sctx;
+	uint16_t first_txq = (sctx->isc_flags & IFLIB_HAS_TXCQ) ? 1 : 0;
+
+	return scctx->isc_ntxd[first_txq];
+}
+
 #ifdef DEV_NETMAP
 #include <sys/selinfo.h>
 #include <net/netmap.h>
@@ -1165,7 +1185,6 @@ static int
 iflib_netmap_attach(if_ctx_t ctx)
 {
 	struct netmap_adapter na;
-	if_softc_ctx_t scctx = &ctx->ifc_softc_ctx;
 
 	bzero(&na, sizeof(na));
 
@@ -1174,8 +1193,8 @@ iflib_netmap_attach(if_ctx_t ctx)
 	MPASS(ctx->ifc_softc_ctx.isc_ntxqsets);
 	MPASS(ctx->ifc_softc_ctx.isc_nrxqsets);
 
-	na.num_tx_desc = scctx->isc_ntxd[0];
-	na.num_rx_desc = scctx->isc_nrxd[0];
+	na.num_tx_desc = iflib_num_tx_descs(ctx);
+	na.num_rx_desc = iflib_num_rx_descs(ctx);
 	na.nm_txsync = iflib_netmap_txsync;
 	na.nm_rxsync = iflib_netmap_rxsync;
 	na.nm_register = iflib_netmap_register;
@@ -4590,7 +4609,7 @@ iflib_device_register(device_t dev, void *sc, if_share
 	kobjop_desc_t kobj_desc;
 	kobj_method_t *kobj_method;
 	int err, msix, rid;
-	uint16_t main_rxq, main_txq;
+	int num_txd, num_rxd;
 
 	ctx = malloc(sizeof(* ctx), M_IFLIB, M_WAITOK|M_ZERO);
 
@@ -4640,21 +4659,20 @@ iflib_device_register(device_t dev, void *sc, if_share
 	if (scctx->isc_nrxqsets == 0 || (scctx->isc_nrxqsets_max && scctx->isc_nrxqsets_max < scctx->isc_nrxqsets))
 		scctx->isc_nrxqsets = scctx->isc_nrxqsets_max;
 
-	main_txq = (sctx->isc_flags & IFLIB_HAS_TXCQ) ? 1 : 0;
-	main_rxq = (sctx->isc_flags & IFLIB_HAS_RXCQ) ? 1 : 0;
+	num_txd = iflib_num_tx_descs(ctx);
+	num_rxd = iflib_num_rx_descs(ctx);
 
 	/* XXX change for per-queue sizes */
 	device_printf(dev, "Using %d TX descriptors and %d RX descriptors\n",
-	    scctx->isc_ntxd[main_txq], scctx->isc_nrxd[main_rxq]);
+	    num_txd, num_rxd);
 
-	if (scctx->isc_tx_nsegments > scctx->isc_ntxd[main_txq] /
-	    MAX_SINGLE_PACKET_FRACTION)
-		scctx->isc_tx_nsegments = max(1, scctx->isc_ntxd[main_txq] /
+	if (scctx->isc_tx_nsegments > num_txd / MAX_SINGLE_PACKET_FRACTION)
+		scctx->isc_tx_nsegments = max(1, num_txd /
 		    MAX_SINGLE_PACKET_FRACTION);
-	if (scctx->isc_tx_tso_segments_max > scctx->isc_ntxd[main_txq] /
+	if (scctx->isc_tx_tso_segments_max > num_txd /
 	    MAX_SINGLE_PACKET_FRACTION)
 		scctx->isc_tx_tso_segments_max = max(1,
-		    scctx->isc_ntxd[main_txq] / MAX_SINGLE_PACKET_FRACTION);
+		    num_txd / MAX_SINGLE_PACKET_FRACTION);
 
 	/* TSO parameters - dig these out of the data sheet - simply correspond to tag setup */
 	if (if_getcapabilities(ifp) & IFCAP_TSO) {
@@ -4831,14 +4849,13 @@ int
 iflib_pseudo_register(device_t dev, if_shared_ctx_t sctx, if_ctx_t *ctxp,
 					  struct iflib_cloneattach_ctx *clctx)
 {
+	int num_txd, num_rxd;
 	int err;
 	if_ctx_t ctx;
 	if_t ifp;
 	if_softc_ctx_t scctx;
 	int i;
 	void *sc;
-	uint16_t main_txq;
-	uint16_t main_rxq;
 
 	ctx = malloc(sizeof(*ctx), M_IFLIB, M_WAITOK|M_ZERO);
 	sc = malloc(sctx->isc_driver->size, M_IFLIB, M_WAITOK|M_ZERO);
@@ -4924,21 +4941,20 @@ iflib_pseudo_register(device_t dev, if_shared_ctx_t sc
 	if (scctx->isc_nrxqsets == 0 || (scctx->isc_nrxqsets_max && scctx->isc_nrxqsets_max < scctx->isc_nrxqsets))
 		scctx->isc_nrxqsets = scctx->isc_nrxqsets_max;
 
-	main_txq = (sctx->isc_flags & IFLIB_HAS_TXCQ) ? 1 : 0;
-	main_rxq = (sctx->isc_flags & IFLIB_HAS_RXCQ) ? 1 : 0;
+	num_txd = iflib_num_tx_descs(ctx);
+	num_rxd = iflib_num_rx_descs(ctx);
 
 	/* XXX change for per-queue sizes */
 	device_printf(dev, "Using %d TX descriptors and %d RX descriptors\n",
-	    scctx->isc_ntxd[main_txq], scctx->isc_nrxd[main_rxq]);
+	    num_txd, num_rxd);
 
-	if (scctx->isc_tx_nsegments > scctx->isc_ntxd[main_txq] /
-	    MAX_SINGLE_PACKET_FRACTION)
-		scctx->isc_tx_nsegments = max(1, scctx->isc_ntxd[main_txq] /
+	if (scctx->isc_tx_nsegments > num_txd / MAX_SINGLE_PACKET_FRACTION)
+		scctx->isc_tx_nsegments = max(1, num_txd /
 		    MAX_SINGLE_PACKET_FRACTION);
-	if (scctx->isc_tx_tso_segments_max > scctx->isc_ntxd[main_txq] /
+	if (scctx->isc_tx_tso_segments_max > num_txd /
 	    MAX_SINGLE_PACKET_FRACTION)
 		scctx->isc_tx_tso_segments_max = max(1,
-		    scctx->isc_ntxd[main_txq] / MAX_SINGLE_PACKET_FRACTION);
+		    num_txd / MAX_SINGLE_PACKET_FRACTION);
 
 	/* TSO parameters - dig these out of the data sheet - simply correspond to tag setup */
 	if (if_getcapabilities(ifp) & IFCAP_TSO) {