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Index: sys/net/if.c
===================================================================
--- sys/net/if.c
+++ sys/net/if.c
@@ -223,6 +223,10 @@
static struct sx ifdescr_sx;
SX_SYSINIT(ifdescr_sx, &ifdescr_sx, "ifnet descr");
+/* global SX-lock for non-critical if_grow_locked() */
+static struct sx ifgrow_sx;
+SX_SYSINIT(ifgrow_sx, &ifgrow_sx, "ifnet grow");
+
void (*ng_ether_link_state_p)(struct ifnet *ifp, int state);
void (*lagg_linkstate_p)(struct ifnet *ifp, int state);
/* These are external hooks for CARP. */
@@ -256,7 +260,8 @@
static void if_attachdomain(void *);
static void if_attachdomain1(struct ifnet *);
static int ifconf(u_long, caddr_t);
-static void *if_grow(void);
+static int if_grow(void);
+static int if_grow_locked(void);
static void if_input_default(struct ifnet *, struct mbuf *);
static int if_requestencap_default(struct ifnet *, struct if_encap_req *);
static void if_route(struct ifnet *, int flag, int fam);
@@ -331,12 +336,16 @@
struct ifnet *
ifnet_byindex_locked(u_short idx)
{
+ struct ifnet *ifp;
- if (idx > V_if_index)
+ /* XXX should assert in epoch(9) section */
+
+ if (idx >= V_if_indexlim)
return (NULL);
- if (V_ifindex_table[idx] == IFNET_HOLD)
- return (NULL);
- return (V_ifindex_table[idx]);
+ ifp = V_ifindex_table[idx];
+ if (ifp == IFNET_HOLD)
+ ifp = NULL;
+ return (ifp);
}
struct ifnet *
@@ -365,39 +374,54 @@
}
/*
- * Allocate an ifindex array entry; return 0 on success or an error on
- * failure.
+ * Allocate an ifindex array entry.
+ * Returns 0 on success or an error on failure.
*/
-static u_short
-ifindex_alloc(void **old)
+static int
+ifindex_alloc_locked(u_short *pindex)
{
- u_short idx;
+ int index;
+ int error;
- IFNET_WLOCK_ASSERT();
/*
- * Try to find an empty slot below V_if_index. If we fail, take the
- * next slot.
+ * Try to find an empty slot below V_if_indexlim.
+ * Else try to grow the pointer array table.
*/
- for (idx = 1; idx <= V_if_index; idx++) {
- if (V_ifindex_table[idx] == NULL)
- break;
+ while (1) {
+ for (index = 1; index < V_if_indexlim; index++) {
+ if (V_ifindex_table[index] == NULL)
+ goto found;
+ }
+ error = if_grow_locked();
+ if (error)
+ return (error);
}
+found:
+ V_ifindex_table[index] = IFNET_HOLD;
+ if (index > V_if_index)
+ V_if_index = index;
+ *pindex = index;
- /* Catch if_index overflow. */
- if (idx >= V_if_indexlim) {
- *old = if_grow();
- return (USHRT_MAX);
- }
- if (idx > V_if_index)
- V_if_index = idx;
- return (idx);
+ return (0); /* success */
}
+static int
+ifindex_alloc(u_short *pindex)
+{
+ int retval;
+
+ sx_xlock(&ifgrow_sx);
+ retval = ifindex_alloc_locked(pindex);
+ sx_xunlock(&ifgrow_sx);
+
+ return (retval);
+}
+
static void
ifindex_free_locked(u_short idx)
{
- IFNET_WLOCK_ASSERT();
+ sx_assert(&ifgrow_sx, SA_XLOCKED);
V_ifindex_table[idx] = NULL;
while (V_if_index > 0 &&
@@ -409,9 +433,9 @@
ifindex_free(u_short idx)
{
- IFNET_WLOCK();
+ sx_xlock(&ifgrow_sx);
ifindex_free_locked(idx);
- IFNET_WUNLOCK();
+ sx_xunlock(&ifgrow_sx);
}
static void
@@ -445,15 +469,11 @@
static void
vnet_if_init(const void *unused __unused)
{
- void *old;
CK_STAILQ_INIT(&V_ifnet);
CK_STAILQ_INIT(&V_ifg_head);
- IFNET_WLOCK();
- old = if_grow(); /* create initial table */
- IFNET_WUNLOCK();
- epoch_wait_preempt(net_epoch_preempt);
- free(old, M_IFNET);
+ if (if_grow() != 0)
+ panic("Cannot create initial table\n");
vnet_if_clone_init();
}
VNET_SYSINIT(vnet_if_init, SI_SUB_INIT_IF, SI_ORDER_SECOND, vnet_if_init,
@@ -489,35 +509,60 @@
vnet_if_return, NULL);
#endif
-
-static void *
-if_grow(void)
+static int
+if_grow_locked(void)
{
+ struct ifnet **old;
+ struct ifnet **next;
+ size_t size;
int oldlim;
- u_int n;
- struct ifnet **e;
- void *old;
- old = NULL;
- IFNET_WLOCK_ASSERT();
+ sx_assert(&ifgrow_sx, SA_XLOCKED);
+
oldlim = V_if_indexlim;
- IFNET_WUNLOCK();
- n = (oldlim << 1) * sizeof(*e);
- e = malloc(n, M_IFNET, M_WAITOK | M_ZERO);
- IFNET_WLOCK();
- if (V_if_indexlim != oldlim) {
- free(e, M_IFNET);
- return (NULL);
- }
- if (V_ifindex_table != NULL) {
- memcpy((caddr_t)e, (caddr_t)V_ifindex_table, n/2);
- old = V_ifindex_table;
- }
+ if (oldlim > USHRT_MAX)
+ return (ENOMEM); /* limit reached */
+
+ size = (oldlim << 1) * sizeof(*next);
+ next = malloc(size, M_IFNET, M_WAITOK | M_ZERO);
+ old = V_ifindex_table;
+
+ if (old != NULL)
+ memcpy((caddr_t)next, (caddr_t)old, size / 2);
+
+ V_ifindex_table = next;
+
+ /*
+ * Make sure all readers see the new table pointer before
+ * freeing the old one, if any:
+ */
+ epoch_wait_preempt(net_epoch_preempt);
+
+ /*
+ * It is now safe to increment the index limit:
+ */
V_if_indexlim <<= 1;
- V_ifindex_table = e;
- return (old);
+
+ /*
+ * Free old ifnet pointer array, if any:
+ */
+ free(old, M_IFNET);
+
+ return (0); /* success */
}
+static int
+if_grow(void)
+{
+ int retval;
+
+ sx_xlock(&ifgrow_sx);
+ retval = if_grow_locked();
+ sx_xunlock(&ifgrow_sx);
+
+ return (retval);
+}
+
/*
* Allocate a struct ifnet and an index for an interface. A layer 2
* common structure will also be allocated if an allocation routine is
@@ -527,22 +572,12 @@
if_alloc(u_char type)
{
struct ifnet *ifp;
- u_short idx;
- void *old;
ifp = malloc(sizeof(struct ifnet), M_IFNET, M_WAITOK|M_ZERO);
- restart:
- IFNET_WLOCK();
- idx = ifindex_alloc(&old);
- if (__predict_false(idx == USHRT_MAX)) {
- IFNET_WUNLOCK();
- epoch_wait_preempt(net_epoch_preempt);
- free(old, M_IFNET);
- goto restart;
- }
- ifnet_setbyindex(idx, IFNET_HOLD);
- IFNET_WUNLOCK();
- ifp->if_index = idx;
+
+ if (ifindex_alloc(&ifp->if_index) != 0)
+ goto err_free;
+
ifp->if_type = type;
ifp->if_alloctype = type;
#ifdef VIMAGE
@@ -550,11 +585,8 @@
#endif
if (if_com_alloc[type] != NULL) {
ifp->if_l2com = if_com_alloc[type](type, ifp);
- if (ifp->if_l2com == NULL) {
- free(ifp, M_IFNET);
- ifindex_free(idx);
- return (NULL);
- }
+ if (ifp->if_l2com == NULL)
+ goto err_free_index;
}
IF_ADDR_LOCK_INIT(ifp);
@@ -576,6 +608,12 @@
ifp->if_pcp = IFNET_PCP_NONE;
ifnet_setbyindex(ifp->if_index, ifp);
return (ifp);
+
+err_free_index:
+ ifindex_free(ifp->if_index);
+err_free:
+ free(ifp, M_IFNET);
+ return (NULL);
}
/*
@@ -628,12 +666,11 @@
ifp->if_flags |= IFF_DYING; /* XXX: Locking */
CURVNET_SET_QUIET(ifp->if_vnet);
- IFNET_WLOCK();
- KASSERT(ifp == ifnet_byindex_locked(ifp->if_index),
+
+ KASSERT(ifp == ifnet_byindex(ifp->if_index),
("%s: freeing unallocated ifnet", ifp->if_xname));
- ifindex_free_locked(ifp->if_index);
- IFNET_WUNLOCK();
+ ifindex_free(ifp->if_index);
if (refcount_release(&ifp->if_refcount))
epoch_call(net_epoch_preempt, &ifp->if_epoch_ctx, if_destroy);
@@ -1235,7 +1272,6 @@
{
struct if_clone *ifc;
u_int bif_dlt, bif_hdrlen;
- void *old;
int rc;
/*
@@ -1257,13 +1293,8 @@
/*
* Unlink the ifnet from ifindex_table[] in current vnet, and shrink
* the if_index for that vnet if possible.
- *
- * NOTE: IFNET_WLOCK/IFNET_WUNLOCK() are assumed to be unvirtualized,
- * or we'd lock on one vnet and unlock on another.
*/
- IFNET_WLOCK();
- ifindex_free_locked(ifp->if_index);
- IFNET_WUNLOCK();
+ ifindex_free(ifp->if_index);
/*
* Perform interface-specific reassignment tasks, if provided by
@@ -1276,17 +1307,11 @@
* Switch to the context of the target vnet.
*/
CURVNET_SET_QUIET(new_vnet);
- restart:
- IFNET_WLOCK();
- ifp->if_index = ifindex_alloc(&old);
- if (__predict_false(ifp->if_index == USHRT_MAX)) {
- IFNET_WUNLOCK();
- epoch_wait_preempt(net_epoch_preempt);
- free(old, M_IFNET);
- goto restart;
- }
+
+ if (ifindex_alloc(&ifp->if_index) != 0)
+ panic("Out of interface numbers moving to new VNET\n");
+
ifnet_setbyindex(ifp->if_index, ifp);
- IFNET_WUNLOCK();
if_attach_internal(ifp, 1, ifc);

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