Author: glebius
Date: Tue Apr 21 20:25:12 2015
New Revision: 281839
URL: https://svnweb.freebsd.org/changeset/base/281839
Log:
Improve carp(4) locking:
- Use the carp_sx to serialize not only CARP ioctls, but also carp_attach()
and carp_detach().
- Use cif_mtx to lock only access to those the linked list.
- These locking changes allow us to do some memory allocations with M_WAITOK
and also properly call callout_drain() in carp_destroy().
- In carp_attach() assert that ifaddr isn't attached. We always come here
with a pristine address from in[6]_control().
Reviewed by: oleg
Sponsored by: Nginx, Inc.
Modified:
head/sys/netinet/ip_carp.c
Modified: head/sys/netinet/ip_carp.c
==============================================================================
--- head/sys/netinet/ip_carp.c Tue Apr 21 20:24:15 2015 (r281838)
+++ head/sys/netinet/ip_carp.c Tue Apr 21 20:25:12 2015 (r281839)
@@ -256,7 +256,7 @@ SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID
#define CIF_LOCK(cif) mtx_lock(&(cif)->cif_mtx)
#define CIF_UNLOCK(cif) mtx_unlock(&(cif)->cif_mtx)
#define CIF_FREE(cif) do { \
- CIF_LOCK_ASSERT(cif); \
+ CIF_LOCK(cif); \
if (TAILQ_EMPTY(&(cif)->cif_vrs)) \
carp_free_if(cif); \
else \
@@ -296,7 +296,6 @@ SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID
static void carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
static struct carp_softc
*carp_alloc(struct ifnet *);
-static void carp_detach_locked(struct ifaddr *);
static void carp_destroy(struct carp_softc *);
static struct carp_if
*carp_alloc_if(struct ifnet *);
@@ -1250,8 +1249,6 @@ carp_multicast_setup(struct carp_if *cif
struct ifnet *ifp = cif->cif_ifp;
int error = 0;
- CIF_LOCK_ASSERT(cif);
-
switch (sa) {
#ifdef INET
case AF_INET:
@@ -1264,9 +1261,7 @@ carp_multicast_setup(struct carp_if *cif
imo->imo_membership = (struct in_multi **)malloc(
(sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
- M_NOWAIT);
- if (imo->imo_membership == NULL)
- return (ENOMEM);
+ M_WAITOK);
imo->imo_mfilters = NULL;
imo->imo_max_memberships = IP_MIN_MEMBERSHIPS;
imo->imo_multicast_vif = -1;
@@ -1296,9 +1291,7 @@ carp_multicast_setup(struct carp_if *cif
im6o->im6o_membership = (struct in6_multi **)malloc(
(sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
- M_ZERO | M_NOWAIT);
- if (im6o->im6o_membership == NULL)
- return (ENOMEM);
+ M_ZERO | M_WAITOK);
im6o->im6o_mfilters = NULL;
im6o->im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
im6o->im6o_multicast_hlim = CARP_DFLTTL;
@@ -1355,7 +1348,8 @@ static void
carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
{
- CIF_LOCK_ASSERT(cif);
+ sx_assert(&carp_sx, SA_XLOCKED);
+
switch (sa) {
#ifdef INET
case AF_INET:
@@ -1504,22 +1498,18 @@ carp_alloc(struct ifnet *ifp)
return (sc);
}
-static int
+static void
carp_grow_ifas(struct carp_softc *sc)
{
struct ifaddr **new;
- CARP_LOCK_ASSERT(sc);
-
- new = malloc(sc->sc_ifasiz * 2, M_CARP, M_NOWAIT|M_ZERO);
- if (new == NULL)
- return (ENOMEM);
+ new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
+ CARP_LOCK(sc);
bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
free(sc->sc_ifas, M_CARP);
sc->sc_ifas = new;
sc->sc_ifasiz *= 2;
-
- return (0);
+ CARP_UNLOCK(sc);
}
static void
@@ -1528,17 +1518,20 @@ carp_destroy(struct carp_softc *sc)
struct ifnet *ifp = sc->sc_carpdev;
struct carp_if *cif = ifp->if_carp;
- CIF_LOCK_ASSERT(cif);
+ sx_assert(&carp_sx, SA_XLOCKED);
+
+ if (sc->sc_suppress)
+ carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
+ CARP_UNLOCK(sc);
+ CIF_LOCK(cif);
TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
+ CIF_UNLOCK(cif);
mtx_lock(&carp_mtx);
LIST_REMOVE(sc, sc_next);
mtx_unlock(&carp_mtx);
- CARP_LOCK(sc);
- if (sc->sc_suppress)
- carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
callout_drain(&sc->sc_ad_tmo);
#ifdef INET
callout_drain(&sc->sc_md_tmo);
@@ -1807,8 +1800,7 @@ carp_attach(struct ifaddr *ifa, int vhid
struct carp_softc *sc;
int index, error;
- if (ifp->if_carp == NULL)
- return (ENOPROTOOPT);
+ KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
@@ -1822,40 +1814,32 @@ carp_attach(struct ifaddr *ifa, int vhid
return (EPROTOTYPE);
}
+ sx_xlock(&carp_sx);
+ if (ifp->if_carp == NULL) {
+ sx_xunlock(&carp_sx);
+ return (ENOPROTOOPT);
+ }
+
CIF_LOCK(cif);
IFNET_FOREACH_CARP(ifp, sc)
if (sc->sc_vhid == vhid)
break;
+ CIF_UNLOCK(cif);
if (sc == NULL) {
- CIF_UNLOCK(cif);
+ sx_xunlock(&carp_sx);
return (ENOENT);
}
- if (ifa->ifa_carp) {
- if (ifa->ifa_carp->sc_vhid != vhid)
- carp_detach_locked(ifa);
- else {
- CIF_UNLOCK(cif);
- return (0);
- }
- }
-
error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
if (error) {
CIF_FREE(cif);
+ sx_xunlock(&carp_sx);
return (error);
}
- CARP_LOCK(sc);
index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
- if ((error = carp_grow_ifas(sc)) != 0) {
- carp_multicast_cleanup(cif,
- ifa->ifa_addr->sa_family);
- CARP_UNLOCK(sc);
- CIF_FREE(cif);
- return (error);
- }
+ carp_grow_ifas(sc);
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
@@ -1873,14 +1857,15 @@ carp_attach(struct ifaddr *ifa, int vhid
}
ifa_ref(ifa);
+
+ CARP_LOCK(sc);
sc->sc_ifas[index - 1] = ifa;
ifa->ifa_carp = sc;
-
carp_hmac_prepare(sc);
carp_sc_state(sc);
-
CARP_UNLOCK(sc);
- CIF_UNLOCK(cif);
+
+ sx_xunlock(&carp_sx);
return (0);
}
@@ -1890,25 +1875,14 @@ carp_detach(struct ifaddr *ifa)
{
struct ifnet *ifp = ifa->ifa_ifp;
struct carp_if *cif = ifp->if_carp;
-
- CIF_LOCK(cif);
- carp_detach_locked(ifa);
- CIF_FREE(cif);
-}
-
-static void
-carp_detach_locked(struct ifaddr *ifa)
-{
- struct ifnet *ifp = ifa->ifa_ifp;
- struct carp_if *cif = ifp->if_carp;
struct carp_softc *sc = ifa->ifa_carp;
int i, index;
KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
- CIF_LOCK_ASSERT(cif);
- CARP_LOCK(sc);
+ sx_xlock(&carp_sx);
+ CARP_LOCK(sc);
/* Shift array. */
index = sc->sc_naddrs + sc->sc_naddrs6;
for (i = 0; i < index; i++)
@@ -1943,11 +1917,14 @@ carp_detach_locked(struct ifaddr *ifa)
carp_hmac_prepare(sc);
carp_sc_state(sc);
- if (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) {
- CARP_UNLOCK(sc);
+ if (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
carp_destroy(sc);
- } else
+ else
CARP_UNLOCK(sc);
+
+ CIF_FREE(cif);
+
+ sx_xunlock(&carp_sx);
}
static void
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