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Defer the work of freeing IPv4 multicast options from a socket to an

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asychronous task.  This avoids tearing down multicast state including
sending IGMP leave messages and reprogramming MAC filters while holding
the per-protocol global pcbinfo lock that is used in the receive path of
packet processing.

Reviewed by:	rwatson
MFC after:	1 month
This commit is contained in:
John Baldwin 2011-12-29 20:41:16 +00:00
parent 1ad7a2570d
commit c23de1f45b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=228969
2 changed files with 39 additions and 3 deletions
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41
sys/netinet/in_mcast.c
View File

@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <sys/ktr.h>
#include <sys/taskqueue.h>
#include <sys/tree.h>
#include <net/if.h>
@ -144,6 +145,8 @@ static void inm_purge(struct in_multi *);
static void inm_reap(struct in_multi *);
static struct ip_moptions *
inp_findmoptions(struct inpcb *);
static void inp_freemoptions_internal(struct ip_moptions *);
static void inp_gcmoptions(void *, int);
static int inp_get_source_filters(struct inpcb *, struct sockopt *);
static int inp_join_group(struct inpcb *, struct sockopt *);
static int inp_leave_group(struct inpcb *, struct sockopt *);
@ -179,6 +182,10 @@ static SYSCTL_NODE(_net_inet_ip_mcast, OID_AUTO, filters,
CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_ip_mcast_filters,
"Per-interface stack-wide source filters");
static STAILQ_HEAD(, ip_moptions) imo_gc_list =
STAILQ_HEAD_INITIALIZER(imo_gc_list);
static struct task imo_gc_task = TASK_INITIALIZER(0, inp_gcmoptions, NULL);
/*
* Inline function which wraps assertions for a valid ifp.
* The ifnet layer will set the ifma's ifp pointer to NULL if the ifp
@ -1518,17 +1525,29 @@ inp_findmoptions(struct inpcb *inp)
}
/*
* Discard the IP multicast options (and source filters).
* Discard the IP multicast options (and source filters). To minimize
* the amount of work done while holding locks such as the INP's
* pcbinfo lock (which is used in the receive path), the free
* operation is performed asynchronously in a separate task.
*
* SMPng: NOTE: assumes INP write lock is held.
*/
void
inp_freemoptions(struct ip_moptions *imo)
{
struct in_mfilter *imf;
size_t idx, nmships;
KASSERT(imo != NULL, ("%s: ip_moptions is NULL", __func__));
IN_MULTI_LOCK();
STAILQ_INSERT_TAIL(&imo_gc_list, imo, imo_link);
IN_MULTI_UNLOCK();
taskqueue_enqueue(taskqueue_thread, &imo_gc_task);
}
static void
inp_freemoptions_internal(struct ip_moptions *imo)
{
struct in_mfilter *imf;
size_t idx, nmships;
nmships = imo->imo_num_memberships;
for (idx = 0; idx < nmships; ++idx) {
@ -1546,6 +1565,22 @@ inp_freemoptions(struct ip_moptions *imo)
free(imo, M_IPMOPTS);
}
static void
inp_gcmoptions(void *context, int pending)
{
struct ip_moptions *imo;
IN_MULTI_LOCK();
while (!STAILQ_EMPTY(&imo_gc_list)) {
imo = STAILQ_FIRST(&imo_gc_list);
STAILQ_REMOVE_HEAD(&imo_gc_list, imo_link);
IN_MULTI_UNLOCK();
inp_freemoptions_internal(imo);
IN_MULTI_LOCK();
}
IN_MULTI_UNLOCK();
}
/*
* Atomically get source filters on a socket for an IPv4 multicast group.
* Called with INP lock held; returns with lock released.

1
sys/netinet/ip_var.h
View File

@ -93,6 +93,7 @@ struct ip_moptions {
u_short imo_max_memberships; /* max memberships this socket */
struct in_multi **imo_membership; /* group memberships */
struct in_mfilter *imo_mfilters; /* source filters */
STAILQ_ENTRY(ip_moptions) imo_link;
};
struct ipstat {