Date: Wed, 10 Jun 2020 19:58:03 +0000 (UTC) From: Vincenzo Maffione <vmaffione@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r362020 - stable/12/sys/dev/netmap Message-ID: <202006101958.05AJw3mj025697@repo.freebsd.org>
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Author: vmaffione Date: Wed Jun 10 19:58:03 2020 New Revision: 362020 URL: https://svnweb.freebsd.org/changeset/base/362020 Log: MFC r361698 netmap: if_vtnet: avoid netmap ring wraparound netmap assumes the one "slot" is left unused to distinguish the empty ring and full ring conditions. This assumption was violated by vtnet_netmap_rxq_populate(). Modified: stable/12/sys/dev/netmap/if_vtnet_netmap.h Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/dev/netmap/if_vtnet_netmap.h ============================================================================== --- stable/12/sys/dev/netmap/if_vtnet_netmap.h Wed Jun 10 19:57:10 2020 (r362019) +++ stable/12/sys/dev/netmap/if_vtnet_netmap.h Wed Jun 10 19:58:03 2020 (r362020) @@ -275,8 +275,8 @@ vtnet_netmap_rxq_populate(struct vtnet_rxq *rxq) /* Expose all the RX netmap buffers we can. In case of no indirect * buffers, the number of netmap slots in the RX ring matches the * maximum number of 2-elements sglist that the RX virtqueue can - * accommodate. */ - error = vtnet_netmap_kring_refill(kring, na->num_rx_desc); + * accommodate (minus 1 to avoid netmap ring wraparound). */ + error = vtnet_netmap_kring_refill(kring, na->num_rx_desc - 1); virtqueue_notify(rxq->vtnrx_vq); return error < 0 ? ENXIO : 0;
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