git: 3183d0b68072 - main - iflib: initialize LRO unconditionally

[Andrew Gallatin]

The branch main has been updated by gallatin:

URL: https://cgit.FreeBSD.org/src/commit/?id=3183d0b68072dda0e80bb6e03c970625f2823e97

commit 3183d0b68072dda0e80bb6e03c970625f2823e97
Author:     Andrew Gallatin <gallatin at FreeBSD.org>
AuthorDate: 2021-04-23 09:51:22 +0000
Commit:     Andrew Gallatin <gallatin at FreeBSD.org>
CommitDate: 2021-04-23 09:55:20 +0000

    iflib: initialize LRO unconditionally
    
    Changes to the LRO code have exposed a bug in iflib where devices
    which are not capable of doing LRO are still calling
    tcp_lro_flush_all(), even when they have not initialized the LRO
    context. This used to be mostly harmless, but the LRO code now sets
    the VNET based on the ifp in the lro context and will try to access it
    through a NULL ifp resulting in a panic at boot.
    
    To fix this, we unconditionally initializes LRO so that we have a
    valid LRO context when calling tcp_lro_flush_all(). One alternative is
    to check the device capabilities before calling tcp_lro_flush_all() or
    adding a new state flag in the ctx. However, it seems unwise to add an
    extra, mostly useless test for higher performance devices when we can
    just initialize LRO for all devices.
    
    Reviewed by: erj, hselasky, markj, olivier
    Sponsored by: Netflix
    Differential Revision: https://reviews.freebsd.org/D29928
---
 sys/net/iflib.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/sys/net/iflib.c b/sys/net/iflib.c
index 6dbaff556a15..fc0814d0fc19 100644
--- a/sys/net/iflib.c
+++ b/sys/net/iflib.c
@@ -5891,15 +5891,13 @@ iflib_rx_structures_setup(if_ctx_t ctx)
 
 	for (q = 0; q < ctx->ifc_softc_ctx.isc_nrxqsets; q++, rxq++) {
 #if defined(INET6) || defined(INET)
-		if (if_getcapabilities(ctx->ifc_ifp) & IFCAP_LRO) {
-			err = tcp_lro_init_args(&rxq->ifr_lc, ctx->ifc_ifp,
-			    TCP_LRO_ENTRIES, min(1024,
-			    ctx->ifc_softc_ctx.isc_nrxd[rxq->ifr_fl_offset]));
-			if (err != 0) {
-				device_printf(ctx->ifc_dev,
-				    "LRO Initialization failed!\n");
-				goto fail;
-			}
+		err = tcp_lro_init_args(&rxq->ifr_lc, ctx->ifc_ifp,
+		    TCP_LRO_ENTRIES, min(1024,
+		    ctx->ifc_softc_ctx.isc_nrxd[rxq->ifr_fl_offset]));
+		if (err != 0) {
+			device_printf(ctx->ifc_dev,
+			    "LRO Initialization failed!\n");
+			goto fail;
 		}
 #endif
 		IFDI_RXQ_SETUP(ctx, rxq->ifr_id);
@@ -5914,8 +5912,7 @@ fail:
 	 */
 	rxq = ctx->ifc_rxqs;
 	for (i = 0; i < q; ++i, rxq++) {
-		if (if_getcapabilities(ctx->ifc_ifp) & IFCAP_LRO)
-			tcp_lro_free(&rxq->ifr_lc);
+		tcp_lro_free(&rxq->ifr_lc);
 	}
 	return (err);
 #endif
@@ -5938,8 +5935,7 @@ iflib_rx_structures_free(if_ctx_t ctx)
 			iflib_dma_free(&rxq->ifr_ifdi[j]);
 		iflib_rx_sds_free(rxq);
 #if defined(INET6) || defined(INET)
-		if (if_getcapabilities(ctx->ifc_ifp) & IFCAP_LRO)
-			tcp_lro_free(&rxq->ifr_lc);
+		tcp_lro_free(&rxq->ifr_lc);
 #endif
 	}
 	free(ctx->ifc_rxqs, M_IFLIB);