The ip6_sf_list has been protected by mca_lock(spin_lock) so that the critical section is atomic context. In order to switch this context, changing locking is needed. The ip6_sf_list actually already protected by RTNL So if it's converted to use RCU, its control path context can be switched to sleepable. But It doesn't remove mca_lock yet because ifmcaddr6 isn't converted to RCU yet. So, It's not fully converted to the sleepable context.
Suggested-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: Taehee Yoo ap420073@gmail.com --- v2 -> v3: - Fix sparse warnings because of rcu annotation v1 -> v2: - Separated from previous big one patch.
include/net/if_inet6.h | 7 +- net/ipv6/mcast.c | 200 ++++++++++++++++++++++++++--------------- 2 files changed, 130 insertions(+), 77 deletions(-)
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h index 062294aeeb6d..7875a3208426 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -97,12 +97,13 @@ struct ipv6_mc_socklist { };
struct ip6_sf_list { - struct ip6_sf_list *sf_next; + struct ip6_sf_list __rcu *sf_next; struct in6_addr sf_addr; unsigned long sf_count[2]; /* include/exclude counts */ unsigned char sf_gsresp; /* include in g & s response? */ unsigned char sf_oldin; /* change state */ unsigned char sf_crcount; /* retrans. left to send */ + struct rcu_head rcu; };
#define MAF_TIMER_RUNNING 0x01 @@ -115,8 +116,8 @@ struct ifmcaddr6 { struct in6_addr mca_addr; struct inet6_dev *idev; struct ifmcaddr6 *next; - struct ip6_sf_list *mca_sources; - struct ip6_sf_list *mca_tomb; + struct ip6_sf_list __rcu *mca_sources; + struct ip6_sf_list __rcu *mca_tomb; unsigned int mca_sfmode; unsigned char mca_crcount; unsigned long mca_sfcount[2]; diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 9da55d23a13c..bc0fb4815c97 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -113,10 +113,25 @@ int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT; */
#define for_each_pmc_rcu(np, pmc) \ - for (pmc = rcu_dereference(np->ipv6_mc_list); \ - pmc != NULL; \ + for (pmc = rcu_dereference((np)->ipv6_mc_list); \ + pmc; \ pmc = rcu_dereference(pmc->next))
+#define for_each_psf_rtnl(mc, psf) \ + for (psf = rtnl_dereference((mc)->mca_sources); \ + psf; \ + psf = rtnl_dereference(psf->sf_next)) + +#define for_each_psf_rcu(mc, psf) \ + for (psf = rcu_dereference((mc)->mca_sources); \ + psf; \ + psf = rcu_dereference(psf->sf_next)) + +#define for_each_psf_tomb(mc, psf) \ + for (psf = rtnl_dereference((mc)->mca_tomb); \ + psf; \ + psf = rtnl_dereference(psf->sf_next)) + static int unsolicited_report_interval(struct inet6_dev *idev) { int iv; @@ -734,10 +749,14 @@ static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im) if (pmc->mca_sfmode == MCAST_INCLUDE) { struct ip6_sf_list *psf;
- pmc->mca_tomb = im->mca_tomb; - pmc->mca_sources = im->mca_sources; - im->mca_tomb = im->mca_sources = NULL; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) + rcu_assign_pointer(pmc->mca_tomb, + rtnl_dereference(im->mca_tomb)); + rcu_assign_pointer(pmc->mca_sources, + rtnl_dereference(im->mca_sources)); + RCU_INIT_POINTER(im->mca_tomb, NULL); + RCU_INIT_POINTER(im->mca_sources, NULL); + + for_each_psf_rtnl(pmc, psf) psf->sf_crcount = pmc->mca_crcount; } spin_unlock_bh(&im->mca_lock); @@ -748,9 +767,9 @@ static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im) { - struct ifmcaddr6 *pmc, *pmc_prev; - struct ip6_sf_list *psf; + struct ip6_sf_list *psf, *sources, *tomb; struct in6_addr *pmca = &im->mca_addr; + struct ifmcaddr6 *pmc, *pmc_prev;
pmc_prev = NULL; for (pmc = idev->mc_tomb; pmc; pmc = pmc->next) { @@ -769,9 +788,16 @@ static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im) if (pmc) { im->idev = pmc->idev; if (im->mca_sfmode == MCAST_INCLUDE) { - swap(im->mca_tomb, pmc->mca_tomb); - swap(im->mca_sources, pmc->mca_sources); - for (psf = im->mca_sources; psf; psf = psf->sf_next) + tomb = rcu_replace_pointer(im->mca_tomb, + rtnl_dereference(pmc->mca_tomb), + lockdep_rtnl_is_held()); + rcu_assign_pointer(pmc->mca_tomb, tomb); + + sources = rcu_replace_pointer(im->mca_sources, + rtnl_dereference(pmc->mca_sources), + lockdep_rtnl_is_held()); + rcu_assign_pointer(pmc->mca_sources, sources); + for_each_psf_rtnl(im, psf) psf->sf_crcount = idev->mc_qrv; } else { im->mca_crcount = idev->mc_qrv; @@ -803,12 +829,12 @@ static void mld_clear_delrec(struct inet6_dev *idev) struct ip6_sf_list *psf, *psf_next;
spin_lock_bh(&pmc->mca_lock); - psf = pmc->mca_tomb; - pmc->mca_tomb = NULL; + psf = rtnl_dereference(pmc->mca_tomb); + RCU_INIT_POINTER(pmc->mca_tomb, NULL); spin_unlock_bh(&pmc->mca_lock); for (; psf; psf = psf_next) { - psf_next = psf->sf_next; - kfree(psf); + psf_next = rtnl_dereference(psf->sf_next); + kfree_rcu(psf, rcu); } } read_unlock_bh(&idev->lock); @@ -990,7 +1016,7 @@ bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group, struct ip6_sf_list *psf;
spin_lock_bh(&mc->mca_lock); - for (psf = mc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rcu(mc, psf) { if (ipv6_addr_equal(&psf->sf_addr, src_addr)) break; } @@ -1089,7 +1115,7 @@ static bool mld_xmarksources(struct ifmcaddr6 *pmc, int nsrcs, int i, scount;
scount = 0; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rcu(pmc, psf) { if (scount == nsrcs) break; for (i = 0; i < nsrcs; i++) { @@ -1122,7 +1148,7 @@ static bool mld_marksources(struct ifmcaddr6 *pmc, int nsrcs, /* mark INCLUDE-mode sources */
scount = 0; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rcu(pmc, psf) { if (scount == nsrcs) break; for (i = 0; i < nsrcs; i++) { @@ -1532,7 +1558,7 @@ mld_scount(struct ifmcaddr6 *pmc, int type, int gdeleted, int sdeleted) struct ip6_sf_list *psf; int scount = 0;
- for (psf = pmc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rtnl(pmc, psf) { if (!is_in(pmc, psf, type, gdeleted, sdeleted)) continue; scount++; @@ -1707,14 +1733,16 @@ static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc, #define AVAILABLE(skb) ((skb) ? skb_availroom(skb) : 0)
static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, - int type, int gdeleted, int sdeleted, int crsend) + int type, int gdeleted, int sdeleted, + int crsend) { + struct ip6_sf_list *psf, *psf_prev, *psf_next; + int scount, stotal, first, isquery, truncate; + struct ip6_sf_list __rcu **psf_list; struct inet6_dev *idev = pmc->idev; struct net_device *dev = idev->dev; - struct mld2_report *pmr; struct mld2_grec *pgr = NULL; - struct ip6_sf_list *psf, *psf_next, *psf_prev, **psf_list; - int scount, stotal, first, isquery, truncate; + struct mld2_report *pmr; unsigned int mtu;
if (pmc->mca_flags & MAF_NOREPORT) @@ -1733,7 +1761,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
psf_list = sdeleted ? &pmc->mca_tomb : &pmc->mca_sources;
- if (!*psf_list) + if (!rcu_access_pointer(*psf_list)) goto empty_source;
pmr = skb ? (struct mld2_report *)skb_transport_header(skb) : NULL; @@ -1749,10 +1777,12 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, } first = 1; psf_prev = NULL; - for (psf = *psf_list; psf; psf = psf_next) { + for (psf = rtnl_dereference(*psf_list); + psf; + psf = psf_next) { struct in6_addr *psrc;
- psf_next = psf->sf_next; + psf_next = rtnl_dereference(psf->sf_next);
if (!is_in(pmc, psf, type, gdeleted, sdeleted) && !crsend) { psf_prev = psf; @@ -1799,10 +1829,12 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, psf->sf_crcount--; if ((sdeleted || gdeleted) && psf->sf_crcount == 0) { if (psf_prev) - psf_prev->sf_next = psf->sf_next; + rcu_assign_pointer(psf_prev->sf_next, + rtnl_dereference(psf->sf_next)); else - *psf_list = psf->sf_next; - kfree(psf); + rcu_assign_pointer(*psf_list, + rtnl_dereference(psf->sf_next)); + kfree_rcu(psf, rcu); continue; } } @@ -1866,21 +1898,26 @@ static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc) /* * remove zero-count source records from a source filter list */ -static void mld_clear_zeros(struct ip6_sf_list **ppsf) +static void mld_clear_zeros(struct ip6_sf_list __rcu **ppsf) { struct ip6_sf_list *psf_prev, *psf_next, *psf;
psf_prev = NULL; - for (psf = *ppsf; psf; psf = psf_next) { - psf_next = psf->sf_next; + for (psf = rtnl_dereference(*ppsf); + psf; + psf = psf_next) { + psf_next = rtnl_dereference(psf->sf_next); if (psf->sf_crcount == 0) { if (psf_prev) - psf_prev->sf_next = psf->sf_next; + rcu_assign_pointer(psf_prev->sf_next, + rtnl_dereference(psf->sf_next)); else - *ppsf = psf->sf_next; - kfree(psf); - } else + rcu_assign_pointer(*ppsf, + rtnl_dereference(psf->sf_next)); + kfree_rcu(psf, rcu); + } else { psf_prev = psf; + } } }
@@ -1913,8 +1950,9 @@ static void mld_send_cr(struct inet6_dev *idev) mld_clear_zeros(&pmc->mca_sources); } } - if (pmc->mca_crcount == 0 && !pmc->mca_tomb && - !pmc->mca_sources) { + if (pmc->mca_crcount == 0 && + !rcu_access_pointer(pmc->mca_tomb) && + !rcu_access_pointer(pmc->mca_sources)) { if (pmc_prev) pmc_prev->next = pmc_next; else @@ -2111,7 +2149,7 @@ static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode, int rv = 0;
psf_prev = NULL; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rtnl(pmc, psf) { if (ipv6_addr_equal(&psf->sf_addr, psfsrc)) break; psf_prev = psf; @@ -2126,17 +2164,22 @@ static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
/* no more filters for this source */ if (psf_prev) - psf_prev->sf_next = psf->sf_next; + rcu_assign_pointer(psf_prev->sf_next, + rtnl_dereference(psf->sf_next)); else - pmc->mca_sources = psf->sf_next; + rcu_assign_pointer(pmc->mca_sources, + rtnl_dereference(psf->sf_next)); + if (psf->sf_oldin && !(pmc->mca_flags & MAF_NOREPORT) && !mld_in_v1_mode(idev)) { psf->sf_crcount = idev->mc_qrv; - psf->sf_next = pmc->mca_tomb; - pmc->mca_tomb = psf; + rcu_assign_pointer(psf->sf_next, + rtnl_dereference(pmc->mca_tomb)); + rcu_assign_pointer(pmc->mca_tomb, psf); rv = 1; - } else - kfree(psf); + } else { + kfree_rcu(psf, rcu); + } } return rv; } @@ -2188,7 +2231,7 @@ static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca, pmc->mca_sfmode = MCAST_INCLUDE; pmc->mca_crcount = idev->mc_qrv; idev->mc_ifc_count = pmc->mca_crcount; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) + for_each_psf_rtnl(pmc, psf) psf->sf_crcount = 0; mld_ifc_event(pmc->idev); } else if (sf_setstate(pmc) || changerec) @@ -2207,7 +2250,7 @@ static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode, struct ip6_sf_list *psf, *psf_prev;
psf_prev = NULL; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rtnl(pmc, psf) { if (ipv6_addr_equal(&psf->sf_addr, psfsrc)) break; psf_prev = psf; @@ -2219,9 +2262,10 @@ static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode,
psf->sf_addr = *psfsrc; if (psf_prev) { - psf_prev->sf_next = psf; - } else - pmc->mca_sources = psf; + rcu_assign_pointer(psf_prev->sf_next, psf); + } else { + rcu_assign_pointer(pmc->mca_sources, psf); + } } psf->sf_count[sfmode]++; return 0; @@ -2232,13 +2276,15 @@ static void sf_markstate(struct ifmcaddr6 *pmc) struct ip6_sf_list *psf; int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];
- for (psf = pmc->mca_sources; psf; psf = psf->sf_next) + for_each_psf_rtnl(pmc, psf) { if (pmc->mca_sfcount[MCAST_EXCLUDE]) { psf->sf_oldin = mca_xcount == psf->sf_count[MCAST_EXCLUDE] && !psf->sf_count[MCAST_INCLUDE]; - } else + } else { psf->sf_oldin = psf->sf_count[MCAST_INCLUDE] != 0; + } + } }
static int sf_setstate(struct ifmcaddr6 *pmc) @@ -2249,7 +2295,7 @@ static int sf_setstate(struct ifmcaddr6 *pmc) int new_in, rv;
rv = 0; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) { + for_each_psf_rtnl(pmc, psf) { if (pmc->mca_sfcount[MCAST_EXCLUDE]) { new_in = mca_xcount == psf->sf_count[MCAST_EXCLUDE] && !psf->sf_count[MCAST_INCLUDE]; @@ -2259,8 +2305,7 @@ static int sf_setstate(struct ifmcaddr6 *pmc) if (!psf->sf_oldin) { struct ip6_sf_list *prev = NULL;
- for (dpsf = pmc->mca_tomb; dpsf; - dpsf = dpsf->sf_next) { + for_each_psf_tomb(pmc, dpsf) { if (ipv6_addr_equal(&dpsf->sf_addr, &psf->sf_addr)) break; @@ -2268,10 +2313,12 @@ static int sf_setstate(struct ifmcaddr6 *pmc) } if (dpsf) { if (prev) - prev->sf_next = dpsf->sf_next; + rcu_assign_pointer(prev->sf_next, + rtnl_dereference(dpsf->sf_next)); else - pmc->mca_tomb = dpsf->sf_next; - kfree(dpsf); + rcu_assign_pointer(pmc->mca_tomb, + rtnl_dereference(dpsf->sf_next)); + kfree_rcu(dpsf, rcu); } psf->sf_crcount = qrv; rv++; @@ -2282,7 +2329,8 @@ static int sf_setstate(struct ifmcaddr6 *pmc) * add or update "delete" records if an active filter * is now inactive */ - for (dpsf = pmc->mca_tomb; dpsf; dpsf = dpsf->sf_next) + + for_each_psf_tomb(pmc, dpsf) if (ipv6_addr_equal(&dpsf->sf_addr, &psf->sf_addr)) break; @@ -2291,9 +2339,9 @@ static int sf_setstate(struct ifmcaddr6 *pmc) if (!dpsf) continue; *dpsf = *psf; - /* pmc->mca_lock held by callers */ - dpsf->sf_next = pmc->mca_tomb; - pmc->mca_tomb = dpsf; + rcu_assign_pointer(dpsf->sf_next, + rtnl_dereference(pmc->mca_tomb)); + rcu_assign_pointer(pmc->mca_tomb, dpsf); } dpsf->sf_crcount = qrv; rv++; @@ -2356,7 +2404,7 @@ static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
pmc->mca_crcount = idev->mc_qrv; idev->mc_ifc_count = pmc->mca_crcount; - for (psf = pmc->mca_sources; psf; psf = psf->sf_next) + for_each_psf_rtnl(pmc, psf) psf->sf_crcount = 0; mld_ifc_event(idev); } else if (sf_setstate(pmc)) @@ -2370,16 +2418,20 @@ static void ip6_mc_clear_src(struct ifmcaddr6 *pmc) { struct ip6_sf_list *psf, *nextpsf;
- for (psf = pmc->mca_tomb; psf; psf = nextpsf) { - nextpsf = psf->sf_next; - kfree(psf); + for (psf = rtnl_dereference(pmc->mca_tomb); + psf; + psf = nextpsf) { + nextpsf = rtnl_dereference(psf->sf_next); + kfree_rcu(psf, rcu); } - pmc->mca_tomb = NULL; - for (psf = pmc->mca_sources; psf; psf = nextpsf) { - nextpsf = psf->sf_next; - kfree(psf); + RCU_INIT_POINTER(pmc->mca_tomb, NULL); + for (psf = rtnl_dereference(pmc->mca_sources); + psf; + psf = nextpsf) { + nextpsf = rtnl_dereference(psf->sf_next); + kfree_rcu(psf, rcu); } - pmc->mca_sources = NULL; + RCU_INIT_POINTER(pmc->mca_sources, NULL); pmc->mca_sfmode = MCAST_EXCLUDE; pmc->mca_sfcount[MCAST_INCLUDE] = 0; pmc->mca_sfcount[MCAST_EXCLUDE] = 1; @@ -2789,7 +2841,7 @@ static inline struct ip6_sf_list *igmp6_mcf_get_first(struct seq_file *seq) im = idev->mc_list; if (likely(im)) { spin_lock_bh(&im->mca_lock); - psf = im->mca_sources; + psf = rcu_dereference(im->mca_sources); if (likely(psf)) { state->im = im; state->idev = idev; @@ -2806,7 +2858,7 @@ static struct ip6_sf_list *igmp6_mcf_get_next(struct seq_file *seq, struct ip6_s { struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);
- psf = psf->sf_next; + psf = rcu_dereference(psf->sf_next); while (!psf) { spin_unlock_bh(&state->im->mca_lock); state->im = state->im->next; @@ -2828,7 +2880,7 @@ static struct ip6_sf_list *igmp6_mcf_get_next(struct seq_file *seq, struct ip6_s if (!state->im) break; spin_lock_bh(&state->im->mca_lock); - psf = state->im->mca_sources; + psf = rcu_dereference(state->im->mca_sources); } out: return psf;