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Split psref_held into internal and public variants. 

For internal use, we expect psrefs to be held by other LWPs when
asking in the cross-call thread whether the target in question is
referenced.

For public use, the caller should not assert about some other LWP
holding a psref.

But the rest of the logic is the same.
This commit is contained in:
riastradh 2016-04-13 08:31:00 +00:00
parent edb41cb359
commit 421ddf539c
1 changed files with 23 additions and 12 deletions
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35
sys/kern/subr_psref.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: subr_psref.c,v 1.3 2016/04/11 13:52:23 riastradh Exp $ */
/* $NetBSD: subr_psref.c,v 1.4 2016/04/13 08:31:00 riastradh Exp $ */
/*-
* Copyright (c) 2016 The NetBSD Foundation, Inc.
@ -64,7 +64,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_psref.c,v 1.3 2016/04/11 13:52:23 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_psref.c,v 1.4 2016/04/13 08:31:00 riastradh Exp $");
#include <sys/types.h>
#include <sys/condvar.h>
@ -80,6 +80,9 @@ __KERNEL_RCSID(0, "$NetBSD: subr_psref.c,v 1.3 2016/04/11 13:52:23 riastradh Exp
LIST_HEAD(psref_head, psref);
static bool _psref_held(const struct psref_target *, struct psref_class *,
bool);
/*
* struct psref_class
*
@ -370,7 +373,7 @@ psreffed_p_xc(void *cookie0, void *cookie1 __unused)
* after xc_wait, which has already issued any necessary memory
* barriers.
*/
if (psref_held(P->target, P->class))
if (_psref_held(P->target, P->class, true))
P->ret = true;
}
@ -430,14 +433,9 @@ psref_target_destroy(struct psref_target *target, struct psref_class *class)
target->prt_class = NULL;
}
/*
* psref_held(target, class)
*
* True if the current CPU holds a passive reference to target,
* false otherwise. May be used only inside assertions.
*/
bool
psref_held(const struct psref_target *target, struct psref_class *class)
static bool
_psref_held(const struct psref_target *target, struct psref_class *class,
bool lwp_mismatch_ok)
{
const struct psref_cpu *pcpu;
const struct psref *psref;
@ -460,7 +458,7 @@ psref_held(const struct psref_target *target, struct psref_class *class)
/* Search through all the references on this CPU. */
LIST_FOREACH(psref, &pcpu->pcpu_head, psref_entry) {
/* Sanity-check the reference. */
KASSERTMSG((psref->psref_lwp == curlwp),
KASSERTMSG((lwp_mismatch_ok || psref->psref_lwp == curlwp),
"passive reference transferred from lwp %p to lwp %p",
psref->psref_lwp, curlwp);
KASSERTMSG((psref->psref_cpu == curcpu()),
@ -480,3 +478,16 @@ psref_held(const struct psref_target *target, struct psref_class *class)
return held;
}
/*
* psref_held(target, class)
*
* True if the current CPU holds a passive reference to target,
* false otherwise. May be used only inside assertions.
*/
bool
psref_held(const struct psref_target *target, struct psref_class *class)
{
return _psref_held(target, class, false);
}