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Tidy up functions related to uidinfo management.

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- reference found uidinfo in uilookup
- reduce nesting by handling shorter cases first
This commit is contained in:
Mateusz Guzik 2014-10-27 20:20:05 +00:00
parent 8101958c4f
commit 8d866b10fc
1 changed files with 47 additions and 45 deletions
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92
sys/kern/kern_resource.c
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@ -1215,6 +1215,7 @@ uihashinit()
/*
* Look up a uidinfo struct for the parameter uid.
* uihashtbl_lock must be locked.
* Increase refcount on uidinfo struct returned.
*/
static struct uidinfo *
uilookup(uid_t uid)
@ -1225,49 +1226,52 @@ uilookup(uid_t uid)
rw_assert(&uihashtbl_lock, RA_LOCKED);
uipp = UIHASH(uid);
LIST_FOREACH(uip, uipp, ui_hash)
if (uip->ui_uid == uid)
if (uip->ui_uid == uid) {
uihold(uip);
break;
}
return (uip);
}
/*
* Find or allocate a struct uidinfo for a particular uid.
* Increase refcount on uidinfo struct returned.
* Returns with uidinfo struct referenced.
* uifree() should be called on a struct uidinfo when released.
*/
struct uidinfo *
uifind(uid_t uid)
{
struct uidinfo *old_uip, *uip;
struct uidinfo *new_uip, *uip;
rw_rlock(&uihashtbl_lock);
uip = uilookup(uid);
if (uip == NULL) {
rw_runlock(&uihashtbl_lock);
uip = malloc(sizeof(*uip), M_UIDINFO, M_WAITOK | M_ZERO);
racct_create(&uip->ui_racct);
rw_wlock(&uihashtbl_lock);
/*
* There's a chance someone created our uidinfo while we
* were in malloc and not holding the lock, so we have to
* make sure we don't insert a duplicate uidinfo.
*/
if ((old_uip = uilookup(uid)) != NULL) {
/* Someone else beat us to it. */
racct_destroy(&uip->ui_racct);
free(uip, M_UIDINFO);
uip = old_uip;
} else {
refcount_init(&uip->ui_ref, 0);
uip->ui_uid = uid;
mtx_init(&uip->ui_vmsize_mtx, "ui_vmsize", NULL,
MTX_DEF);
LIST_INSERT_HEAD(UIHASH(uid), uip, ui_hash);
}
rw_runlock(&uihashtbl_lock);
if (uip != NULL)
return (uip);
new_uip = malloc(sizeof(*new_uip), M_UIDINFO, M_WAITOK | M_ZERO);
racct_create(&new_uip->ui_racct);
refcount_init(&new_uip->ui_ref, 1);
new_uip->ui_uid = uid;
mtx_init(&new_uip->ui_vmsize_mtx, "ui_vmsize", NULL, MTX_DEF);
rw_wlock(&uihashtbl_lock);
/*
* There's a chance someone created our uidinfo while we
* were in malloc and not holding the lock, so we have to
* make sure we don't insert a duplicate uidinfo.
*/
if ((uip = uilookup(uid)) == NULL) {
LIST_INSERT_HEAD(UIHASH(uid), new_uip, ui_hash);
rw_wunlock(&uihashtbl_lock);
uip = new_uip;
} else {
rw_wunlock(&uihashtbl_lock);
racct_destroy(&new_uip->ui_racct);
mtx_destroy(&new_uip->ui_vmsize_mtx);
free(new_uip, M_UIDINFO);
}
uihold(uip);
rw_unlock(&uihashtbl_lock);
return (uip);
}
@ -1308,28 +1312,26 @@ uifree(struct uidinfo *uip)
/* Prepare for suboptimal case. */
rw_wlock(&uihashtbl_lock);
if (refcount_release(&uip->ui_ref)) {
racct_destroy(&uip->ui_racct);
LIST_REMOVE(uip, ui_hash);
if (refcount_release(&uip->ui_ref) == 0) {
rw_wunlock(&uihashtbl_lock);
if (uip->ui_sbsize != 0)
printf("freeing uidinfo: uid = %d, sbsize = %ld\n",
uip->ui_uid, uip->ui_sbsize);
if (uip->ui_proccnt != 0)
printf("freeing uidinfo: uid = %d, proccnt = %ld\n",
uip->ui_uid, uip->ui_proccnt);
if (uip->ui_vmsize != 0)
printf("freeing uidinfo: uid = %d, swapuse = %lld\n",
uip->ui_uid, (unsigned long long)uip->ui_vmsize);
mtx_destroy(&uip->ui_vmsize_mtx);
free(uip, M_UIDINFO);
return;
}
/*
* Someone added a reference between atomic_cmpset_int() and
* rw_wlock(&uihashtbl_lock).
*/
racct_destroy(&uip->ui_racct);
LIST_REMOVE(uip, ui_hash);
rw_wunlock(&uihashtbl_lock);
if (uip->ui_sbsize != 0)
printf("freeing uidinfo: uid = %d, sbsize = %ld\n",
uip->ui_uid, uip->ui_sbsize);
if (uip->ui_proccnt != 0)
printf("freeing uidinfo: uid = %d, proccnt = %ld\n",
uip->ui_uid, uip->ui_proccnt);
if (uip->ui_vmsize != 0)
printf("freeing uidinfo: uid = %d, swapuse = %lld\n",
uip->ui_uid, (unsigned long long)uip->ui_vmsize);
mtx_destroy(&uip->ui_vmsize_mtx);
free(uip, M_UIDINFO);
}
void