-/* $OpenBSD: if.c,v 1.672 2022/11/08 21:07:33 kn Exp $ */
+/* $OpenBSD: if.c,v 1.673 2022/11/09 10:41:18 dlg Exp $ */
/* $NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $ */
/*
#include <sys/proc.h>
#include <sys/stdint.h> /* uintptr_t */
#include <sys/rwlock.h>
+#include <sys/smr.h>
#include <net/if.h>
#include <net/if_dl.h>
void if_map_dtor(void *, void *);
struct ifnet *if_ref(struct ifnet *);
-/*
- * struct if_map
- *
- * bounded array of ifnet srp pointers used to fetch references of live
- * interfaces with if_get().
- */
-
-struct if_map {
- unsigned long limit;
- /* followed by limit ifnet srp pointers */
-};
-
/*
* struct if_idxmap
*
* infrastructure to manage updates and accesses to the current if_map.
+ *
+ * interface index 0 is special and represents "no interface", so we
+ * use the 0th slot in map to store the length of the array.
*/
struct if_idxmap {
- unsigned int serial;
- unsigned int count;
- struct srp map;
- struct rwlock lock;
- unsigned char *usedidx; /* bitmap of indices in use */
+ unsigned int serial;
+ unsigned int count;
+ struct ifnet **map; /* SMR protected */
+ struct rwlock lock;
+ unsigned char *usedidx; /* bitmap of indices in use */
};
void if_idxmap_init(unsigned int);
* most machines boot with 4 or 5 interfaces, so size the initial map
* to accommodate this
*/
- if_idxmap_init(8);
+ if_idxmap_init(8); /* 8 is a nice power of 2 for malloc */
for (i = 0; i < NET_TASKQ; i++) {
nettqmp[i] = taskq_create("softnet", 1, IPL_NET, TASKQ_MPSAFE);
}
}
-static struct if_idxmap if_idxmap = {
- 0,
- 0,
- SRP_INITIALIZER(),
- RWLOCK_INITIALIZER("idxmaplk"),
- NULL,
-};
-
-struct srp_gc if_ifp_gc = SRP_GC_INITIALIZER(if_ifp_dtor, NULL);
-struct srp_gc if_map_gc = SRP_GC_INITIALIZER(if_map_dtor, NULL);
+static struct if_idxmap if_idxmap;
struct ifnet_head ifnetlist = TAILQ_HEAD_INITIALIZER(ifnetlist);
+static inline unsigned int
+if_idxmap_limit(struct ifnet **if_map)
+{
+ return ((uintptr_t)if_map[0]);
+}
+
void
if_idxmap_init(unsigned int limit)
{
- struct if_map *if_map;
- struct srp *map;
- unsigned int i;
+ struct ifnet **if_map;
- if_idxmap.serial = 1; /* skip ifidx 0 so it can return NULL */
+ rw_init(&if_idxmap.lock, "idxmaplk");
+ if_idxmap.serial = 1; /* skip ifidx 0 */
- if_map = malloc(sizeof(*if_map) + limit * sizeof(*map),
- M_IFADDR, M_WAITOK);
+ if_map = mallocarray(limit, sizeof(*if_map), M_IFADDR,
+ M_WAITOK | M_ZERO);
- if_map->limit = limit;
- map = (struct srp *)(if_map + 1);
- for (i = 0; i < limit; i++)
- srp_init(&map[i]);
+ if_map[0] = (struct ifnet *)(uintptr_t)limit;
if_idxmap.usedidx = malloc(howmany(limit, NBBY),
M_IFADDR, M_WAITOK | M_ZERO);
/* this is called early so there's nothing to race with */
- srp_update_locked(&if_map_gc, &if_idxmap.map, if_map);
+ SMR_PTR_SET_LOCKED(&if_idxmap.map, if_map);
}
void
if_idxmap_alloc(struct ifnet *ifp)
{
- struct if_map *if_map;
- struct srp *map;
+ struct ifnet **if_map, **oif_map = NULL;
+ unsigned int limit, olimit;
unsigned int index, i;
refcnt_init(&ifp->if_refcnt);
if (++if_idxmap.count >= USHRT_MAX)
panic("too many interfaces");
- if_map = srp_get_locked(&if_idxmap.map);
- map = (struct srp *)(if_map + 1);
+ if_map = SMR_PTR_GET_LOCKED(&if_idxmap.map);
+ limit = if_idxmap_limit(if_map);
index = if_idxmap.serial++ & USHRT_MAX;
- if (index >= if_map->limit) {
- struct if_map *nif_map;
- struct srp *nmap;
- unsigned int nlimit;
- struct ifnet *nifp;
+ if (index >= limit) {
unsigned char *nusedidx;
- nlimit = if_map->limit * 2;
- nif_map = malloc(sizeof(*nif_map) + nlimit * sizeof(*nmap),
- M_IFADDR, M_WAITOK);
- nmap = (struct srp *)(nif_map + 1);
-
- nif_map->limit = nlimit;
- for (i = 0; i < if_map->limit; i++) {
- srp_init(&nmap[i]);
- nifp = srp_get_locked(&map[i]);
- if (nifp != NULL) {
- srp_update_locked(&if_ifp_gc, &nmap[i],
- if_ref(nifp));
- }
- }
+ oif_map = if_map;
+ olimit = limit;
+
+ limit = olimit * 2;
+ if_map = mallocarray(limit, sizeof(*if_map), M_IFADDR,
+ M_WAITOK | M_ZERO);
+ if_map[0] = (struct ifnet *)(uintptr_t)limit;
+
+ for (i = 1; i < olimit; i++) {
+ struct ifnet *oifp = SMR_PTR_GET_LOCKED(&oif_map[i]);
+ if (oifp == NULL)
+ continue;
- while (i < nlimit) {
- srp_init(&nmap[i]);
- i++;
+ /*
+ * nif_map isn't visible yet, so don't need
+ * SMR_PTR_SET_LOCKED and its membar.
+ */
+ if_map[i] = if_ref(oifp);
}
- nusedidx = malloc(howmany(nlimit, NBBY),
+ nusedidx = malloc(howmany(limit, NBBY),
M_IFADDR, M_WAITOK | M_ZERO);
- memcpy(nusedidx, if_idxmap.usedidx,
- howmany(if_map->limit, NBBY));
- free(if_idxmap.usedidx, M_IFADDR,
- howmany(if_map->limit, NBBY));
+ memcpy(nusedidx, if_idxmap.usedidx, howmany(olimit, NBBY));
+ free(if_idxmap.usedidx, M_IFADDR, howmany(olimit, NBBY));
if_idxmap.usedidx = nusedidx;
- srp_update_locked(&if_map_gc, &if_idxmap.map, nif_map);
- if_map = nif_map;
- map = nmap;
+ SMR_PTR_SET_LOCKED(&if_idxmap.map, if_map);
}
/* pick the next free index */
index = if_idxmap.serial++ & USHRT_MAX;
}
- KASSERT(index != 0 && index < if_map->limit);
+ KASSERT(index != 0 && index < limit);
KASSERT(isclr(if_idxmap.usedidx, index));
setbit(if_idxmap.usedidx, index);
ifp->if_index = index;
rw_exit_write(&if_idxmap.lock);
+
+ if (oif_map != NULL) {
+ smr_barrier();
+ for (i = 1; i < olimit; i++)
+ if_put(oif_map[i]);
+ free(oif_map, M_IFADDR, olimit * sizeof(*oif_map));
+ }
}
void
if_idxmap_insert(struct ifnet *ifp)
{
- struct if_map *if_map;
- struct srp *map;
+ struct ifnet **if_map;
unsigned int index = ifp->if_index;
rw_enter_write(&if_idxmap.lock);
- if_map = srp_get_locked(&if_idxmap.map);
- map = (struct srp *)(if_map + 1);
+ if_map = SMR_PTR_GET_LOCKED(&if_idxmap.map);
- KASSERT(index != 0 && index < if_map->limit);
+ KASSERTMSG(index != 0 && index < if_idxmap_limit(if_map),
+ "%s(%p) index %u vs limit %u", ifp->if_xname, ifp, index,
+ if_idxmap_limit(if_map));
+ KASSERT(SMR_PTR_GET_LOCKED(&if_map[index]) == NULL);
KASSERT(isset(if_idxmap.usedidx, index));
/* commit */
- srp_update_locked(&if_ifp_gc, &map[index], if_ref(ifp));
+ SMR_PTR_SET_LOCKED(&if_map[index], if_ref(ifp));
rw_exit_write(&if_idxmap.lock);
}
void
if_idxmap_remove(struct ifnet *ifp)
{
- struct if_map *if_map;
- struct srp *map;
- unsigned int index;
-
- index = ifp->if_index;
+ struct ifnet **if_map;
+ unsigned int index = ifp->if_index;
rw_enter_write(&if_idxmap.lock);
- if_map = srp_get_locked(&if_idxmap.map);
- KASSERT(index < if_map->limit);
+ if_map = SMR_PTR_GET_LOCKED(&if_idxmap.map);
+
+ KASSERT(index != 0 && index < if_idxmap_limit(if_map));
+ KASSERT(SMR_PTR_GET_LOCKED(&if_map[index]) == ifp);
+ KASSERT(isset(if_idxmap.usedidx, index));
- map = (struct srp *)(if_map + 1);
- KASSERT(ifp == (struct ifnet *)srp_get_locked(&map[index]));
+ SMR_PTR_SET_LOCKED(&if_map[index], NULL);
- srp_update_locked(&if_ifp_gc, &map[index], NULL);
if_idxmap.count--;
-
- KASSERT(isset(if_idxmap.usedidx, index));
clrbit(if_idxmap.usedidx, index);
/* end of if_idxmap modifications */
rw_exit_write(&if_idxmap.lock);
-}
-void
-if_ifp_dtor(void *null, void *ifp)
-{
+ smr_barrier();
if_put(ifp);
}
-void
-if_map_dtor(void *null, void *m)
-{
- struct if_map *if_map = m;
- struct srp *map = (struct srp *)(if_map + 1);
- unsigned int i;
-
- /*
- * dont need to serialize the use of update_locked since this is
- * the last reference to this map. there's nothing to race against.
- */
- for (i = 0; i < if_map->limit; i++)
- srp_update_locked(&if_ifp_gc, &map[i], NULL);
-
- free(if_map, M_IFADDR, sizeof(*if_map) + if_map->limit * sizeof(*map));
-}
-
/*
* Attach an interface to the
* list of "active" interfaces.
t |= n;
}
-#if NPFSYNC > 0
- if (t & (1 << NETISR_PFSYNC)) {
- KERNEL_LOCK();
- pfsyncintr();
- KERNEL_UNLOCK();
- }
-#endif
-
NET_UNLOCK();
}
struct ifnet *
if_get(unsigned int index)
{
- struct srp_ref sr;
- struct if_map *if_map;
- struct srp *map;
+ struct ifnet **if_map;
struct ifnet *ifp = NULL;
- if_map = srp_enter(&sr, &if_idxmap.map);
- if (index < if_map->limit) {
- map = (struct srp *)(if_map + 1);
+ if (index == 0)
+ return (NULL);
- ifp = srp_follow(&sr, &map[index]);
+ smr_read_enter();
+ if_map = SMR_PTR_GET(&if_idxmap.map);
+ if (index < if_idxmap_limit(if_map)) {
+ ifp = SMR_PTR_GET(&if_map[index]);
if (ifp != NULL) {
KASSERT(ifp->if_index == index);
if_ref(ifp);
}
}
- srp_leave(&sr);
+ smr_read_leave();
return (ifp);
}
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