v3: 1) rebased on 3.5-rc3 kernel. v2: destruction of currently processing transport added: 1) Added marking of currently processing transports with XPT_CLOSE on per-net shutdown. These transports will be destroyed in svc_xprt_enqueue() (instead of enqueueing). 2) newly created temporary transport in svc_recv() will be destroyed, if it's "parent" was marked with XPT_CLOSE. 3) spin_lock(&serv->sv_lock) was replaced by spin_lock_bh() in svc_close_net(&serv->sv_lock).
Service sv_tempsocks and sv_permsocks lists are accessible by tasks with different network namespaces, and thus per-net service destruction must be protected. These lists are protected by service sv_lock. So lets wrap list munipulations with this lock and move tranports destruction outside wrapped area to prevent deadlocks. Signed-off-by: Stanislav Kinsbursky <[email protected]> --- net/sunrpc/svc_xprt.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++--- 1 files changed, 52 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 88f2bf6..4af2114 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -320,6 +320,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt) struct svc_pool *pool; struct svc_rqst *rqstp; int cpu; + int destroy = 0; if (!svc_xprt_has_something_to_do(xprt)) return; @@ -338,6 +339,17 @@ void svc_xprt_enqueue(struct svc_xprt *xprt) pool->sp_stats.packets++; + /* + * Check transport close flag. It could be marked as closed on per-net + * service shutdown. + */ + if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) { + /* Don't enqueue transport if it has to be destroyed. */ + dprintk("svc: transport %p have to be closed\n", xprt); + destroy++; + goto out_unlock; + } + /* Mark transport as busy. It will remain in this state until * the provider calls svc_xprt_received. We update XPT_BUSY * atomically because it also guards against trying to enqueue @@ -374,6 +386,8 @@ void svc_xprt_enqueue(struct svc_xprt *xprt) out_unlock: spin_unlock_bh(&pool->sp_lock); + if (destroy) + svc_delete_xprt(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_enqueue); @@ -714,6 +728,13 @@ int svc_recv(struct svc_rqst *rqstp, long timeout) __module_get(newxpt->xpt_class->xcl_owner); svc_check_conn_limits(xprt->xpt_server); spin_lock_bh(&serv->sv_lock); + if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) { + dprintk("svc_recv: found XPT_CLOSE on listener\n"); + set_bit(XPT_DETACHED, &newxpt->xpt_flags); + spin_unlock_bh(&pool->sp_lock); + svc_delete_xprt(newxpt); + goto out_closed; + } set_bit(XPT_TEMP, &newxpt->xpt_flags); list_add(&newxpt->xpt_list, &serv->sv_tempsocks); serv->sv_tmpcnt++; @@ -739,6 +760,7 @@ int svc_recv(struct svc_rqst *rqstp, long timeout) len = xprt->xpt_ops->xpo_recvfrom(rqstp); dprintk("svc: got len=%d\n", len); } +out_closed: svc_xprt_received(xprt); /* No data, incomplete (TCP) read, or accept() */ @@ -936,6 +958,7 @@ static void svc_clear_pools(struct svc_serv *serv, struct net *net) struct svc_pool *pool; struct svc_xprt *xprt; struct svc_xprt *tmp; + struct svc_rqst *rqstp; int i; for (i = 0; i < serv->sv_nrpools; i++) { @@ -947,11 +970,16 @@ static void svc_clear_pools(struct svc_serv *serv, struct net *net) continue; list_del_init(&xprt->xpt_ready); } + list_for_each_entry(rqstp, &pool->sp_all_threads, rq_all) { + if (rqstp->rq_xprt && rqstp->rq_xprt->xpt_net == net) + set_bit(XPT_CLOSE, &rqstp->rq_xprt->xpt_flags); + } spin_unlock_bh(&pool->sp_lock); } } -static void svc_clear_list(struct list_head *xprt_list, struct net *net) +static void svc_clear_list(struct list_head *xprt_list, struct net *net, + struct list_head *kill_list) { struct svc_xprt *xprt; struct svc_xprt *tmp; @@ -959,7 +987,8 @@ static void svc_clear_list(struct list_head *xprt_list, struct net *net) list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) { if (xprt->xpt_net != net) continue; - svc_delete_xprt(xprt); + list_move(&xprt->xpt_list, kill_list); + set_bit(XPT_DETACHED, &xprt->xpt_flags); } list_for_each_entry(xprt, xprt_list, xpt_list) BUG_ON(xprt->xpt_net == net); @@ -967,6 +996,15 @@ static void svc_clear_list(struct list_head *xprt_list, struct net *net) void svc_close_net(struct svc_serv *serv, struct net *net) { + struct svc_xprt *xprt, *tmp; + LIST_HEAD(kill_list); + + /* + * Protect the lists, since they can be by tasks with different network + * namespace contexts. + */ + spin_lock_bh(&serv->sv_lock); + svc_close_list(&serv->sv_tempsocks, net); svc_close_list(&serv->sv_permsocks, net); @@ -976,8 +1014,18 @@ void svc_close_net(struct svc_serv *serv, struct net *net) * svc_xprt_enqueue will not add new entries without taking the * sp_lock and checking XPT_BUSY. */ - svc_clear_list(&serv->sv_tempsocks, net); - svc_clear_list(&serv->sv_permsocks, net); + svc_clear_list(&serv->sv_tempsocks, net, &kill_list); + svc_clear_list(&serv->sv_permsocks, net, &kill_list); + + spin_unlock_bh(&serv->sv_lock); + + /* + * Destroy collected transports. + * Note: tranports has been marked as XPT_DETACHED on svc_clear_list(), + * so no need to protect againt list_del() in svc_delete_xprt(). + */ + list_for_each_entry_safe(xprt, tmp, &kill_list, xpt_list) + svc_delete_xprt(xprt); } /* _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
