Date: Wed, 27 May 2009 06:04:38 +0000 (UTC) From: Adrian Chadd <adrian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r192876 - head/sys/dev/xen/netfront Message-ID: <200905270604.n4R64cRR085519@svn.freebsd.org>
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Author: adrian Date: Wed May 27 06:04:38 2009 New Revision: 192876 URL: http://svn.freebsd.org/changeset/base/192876 Log: Enforce that there are actually enough xenbus TX ring descriptors available before attempting to queue the packet. Modified: head/sys/dev/xen/netfront/netfront.c Modified: head/sys/dev/xen/netfront/netfront.c ============================================================================== --- head/sys/dev/xen/netfront/netfront.c Wed May 27 05:37:04 2009 (r192875) +++ head/sys/dev/xen/netfront/netfront.c Wed May 27 06:04:38 2009 (r192876) @@ -1478,10 +1478,20 @@ xn_start_locked(struct ifnet *ifp) } /* - * XXX TODO - make sure there's actually space available - * in the Xen TX ring for this rather than the hacky way - * its currently done. + * Make sure there's actually space available in the + * Xen TX ring for this. Overcompensate for the possibility + * of having a TCP offload fragment just in case for now + * (the +1) rather than adding logic to accurately calculate + * the required size. */ + if (RING_FREE_REQUESTS(&sc->tx) < (nfrags + 1)) { + printf("xn_start_locked: free ring slots (%d) < (nfrags + 1) (%d); must be full!\n", + (int) RING_FREE_REQUESTS(&sc->tx), + (int) (nfrags + 1)); + IF_PREPEND(&ifp->if_snd, m_head); + ifp->if_drv_flags |= IFF_DRV_OACTIVE; + break; + } /* * Start packing the mbufs in this chain into
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