Date: Tue, 16 Nov 2010 07:57:56 +0000 (UTC) From: Lawrence Stewart <lstewart@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r215391 - head/sys/netinet/cc Message-ID: <201011160757.oAG7vuVJ044748@svn.freebsd.org>
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Author: lstewart Date: Tue Nov 16 07:57:56 2010 New Revision: 215391 URL: http://svn.freebsd.org/changeset/base/215391 Log: On CC algorithm module unload, we walk the list of active TCP control blocks. Any found to be using the algorithm that is about to go away are switched back to NewReno to avoid leaving dangling pointers which would trigger a panic. For VIMAGE kernels, there is a list per vnet to walk, yet the implementation was only examining one of the vnet lists. Fix the implementation of the above feature for VIMAGE kernels by looping through all active TCP control blocks across all vnets. Sponsored by: FreeBSD Foundation Tested by: Mikolaj Golub <to.my.trociny at gmail com> Reviewed by: bz (briefly) MFC after: 11 weeks Modified: head/sys/netinet/cc/cc.c Modified: head/sys/netinet/cc/cc.c ============================================================================== --- head/sys/netinet/cc/cc.c Tue Nov 16 07:55:36 2010 (r215390) +++ head/sys/netinet/cc/cc.c Tue Nov 16 07:57:56 2010 (r215391) @@ -193,6 +193,7 @@ cc_deregister_algo(struct cc_algo *remov struct tcpcb *tp; struct inpcb *inp; int err; + VNET_ITERATOR_DECL(vnet_iter); err = ENOENT; @@ -221,9 +222,10 @@ cc_deregister_algo(struct cc_algo *remov if (!err) { /* - * Check all active control blocks and change any that are - * using this algorithm back to newreno. If the algorithm that - * was in use requires cleanup code to be run, call it. + * Check all active control blocks across all network stacks and + * change any that are using this algorithm back to newreno. If + * the algorithm that was in use requires cleanup code to be + * run, call it. * * New connections already part way through being initialised * with the CC algo we're removing will not race with this code @@ -231,30 +233,39 @@ cc_deregister_algo(struct cc_algo *remov * We therefore don't enter the loop below until the connection * list has stabilised. */ - INP_INFO_RLOCK(&V_tcbinfo); - LIST_FOREACH(inp, &V_tcb, inp_list) { - INP_WLOCK(inp); - /* Important to skip tcptw structs. */ - if (!(inp->inp_flags & INP_TIMEWAIT) && - (tp = intotcpcb(inp)) != NULL) { - /* - * By holding INP_WLOCK here, we are - * assured that the connection is not - * currently executing inside the CC - * module's functions i.e. it is safe to - * make the switch back to newreno. - */ - if (CC_ALGO(tp) == remove_cc) { - tmpfuncs = CC_ALGO(tp); - /* Newreno does not require any init. */ - CC_ALGO(tp) = &newreno_cc_algo; - if (tmpfuncs->cb_destroy != NULL) - tmpfuncs->cb_destroy(tp->ccv); + VNET_LIST_RLOCK(); + VNET_FOREACH(vnet_iter) { + CURVNET_SET(vnet_iter); + INP_INFO_RLOCK(&V_tcbinfo); + LIST_FOREACH(inp, &V_tcb, inp_list) { + INP_WLOCK(inp); + /* Important to skip tcptw structs. */ + if (!(inp->inp_flags & INP_TIMEWAIT) && + (tp = intotcpcb(inp)) != NULL) { + /* + * By holding INP_WLOCK here, we are + * assured that the connection is not + * currently executing inside the CC + * module's functions i.e. it is safe + * to make the switch back to newreno. + */ + if (CC_ALGO(tp) == remove_cc) { + tmpfuncs = CC_ALGO(tp); + /* + * Newreno does not + * require any init. + */ + CC_ALGO(tp) = &newreno_cc_algo; + if (tmpfuncs->cb_destroy != NULL) + tmpfuncs->cb_destroy(tp->ccv); + } } + INP_WUNLOCK(inp); } - INP_WUNLOCK(inp); + INP_INFO_RUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); } - INP_INFO_RUNLOCK(&V_tcbinfo); + VNET_LIST_RUNLOCK(); } return (err);
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