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Remove Giant locking from domains list.

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During boot, the domain list is locked with Giant. It is not possible to
register any protocols after the system has booted, so the lock is only
used to protect insertion of entries.

There is already a mutex in uipc_domain.c called dom_mtx. Use this mutex
to lock the list, instead of using Giant. It won't matter anything with
respect to performance, but we'll never get rid of Giant if we don't
remove from places where we don't need it.

Approved by:	rwatson
MFC after:	3 weeks
This commit is contained in:
Ed Schouten 2009-01-04 19:22:53 +00:00
parent 192a6120fc
commit fdef61da21
1 changed files with 9 additions and 9 deletions
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18
sys/kern/uipc_domain.c
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@ -72,7 +72,7 @@ static void pfslowtimo(void *);
struct domain *domains; /* registered protocol domains */
int domain_init_status = 0;
struct mtx dom_mtx; /* domain list lock */
static struct mtx dom_mtx; /* domain list lock */
MTX_SYSINIT(domain, &dom_mtx, "domain list", MTX_DEF);
/*
@ -338,13 +338,13 @@ pf_proto_register(int family, struct protosw *npr)
* Protect us against races when two protocol registrations for
* the same protocol happen at the same time.
*/
mtx_lock(&Giant);
mtx_lock(&dom_mtx);
/* The new protocol must not yet exist. */
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
if ((pr->pr_type == npr->pr_type) &&
(pr->pr_protocol == npr->pr_protocol)) {
mtx_unlock(&Giant);
mtx_unlock(&dom_mtx);
return (EEXIST); /* XXX: Check only protocol? */
}
/* While here, remember the first free spacer. */
@ -354,7 +354,7 @@ pf_proto_register(int family, struct protosw *npr)
/* If no free spacer is found we can't add the new protocol. */
if (fpr == NULL) {
mtx_unlock(&Giant);
mtx_unlock(&dom_mtx);
return (ENOMEM);
}
@ -362,7 +362,7 @@ pf_proto_register(int family, struct protosw *npr)
bcopy(npr, fpr, sizeof(*fpr));
/* Job is done, no more protection required. */
mtx_unlock(&Giant);
mtx_unlock(&dom_mtx);
/* Initialize and activate the protocol. */
protosw_init(fpr);
@ -398,13 +398,13 @@ pf_proto_unregister(int family, int protocol, int type)
dpr = NULL;
/* Lock out everyone else while we are manipulating the protosw. */
mtx_lock(&Giant);
mtx_lock(&dom_mtx);
/* The protocol must exist and only once. */
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
if ((pr->pr_type == type) && (pr->pr_protocol == protocol)) {
if (dpr != NULL) {
mtx_unlock(&Giant);
mtx_unlock(&dom_mtx);
return (EMLINK); /* Should not happen! */
} else
dpr = pr;
@ -413,7 +413,7 @@ pf_proto_unregister(int family, int protocol, int type)
/* Protocol does not exist. */
if (dpr == NULL) {
mtx_unlock(&Giant);
mtx_unlock(&dom_mtx);
return (EPROTONOSUPPORT);
}
@ -433,7 +433,7 @@ pf_proto_unregister(int family, int protocol, int type)
dpr->pr_usrreqs = &nousrreqs;
/* Job is done, not more protection required. */
mtx_unlock(&Giant);
mtx_unlock(&dom_mtx);
return (0);
}