Use more KASSERT()s instead of the "if (x) panic()" idiom for sanity
checks and add a couple of local variables to reduce the difference
with NetBSD and help for upcoming locking.
ok?
Index: uvm/uvm_amap.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_amap.c,v
retrieving revision 1.84
diff -u -p -r1.84 uvm_amap.c
--- uvm/uvm_amap.c 25 Sep 2020 08:04:48 -0000 1.84
+++ uvm/uvm_amap.c 1 Oct 2020 12:13:23 -0000
@@ -460,8 +460,7 @@ amap_wipeout(struct vm_amap *amap)
map ^= 1 << slot;
anon = chunk->ac_anon[slot];
- if (anon == NULL || anon->an_ref == 0)
- panic("amap_wipeout: corrupt amap");
+ KASSERT(anon != NULL && anon->an_ref != 0);
refs = --anon->an_ref;
if (refs == 0) {
@@ -669,9 +668,7 @@ ReStart:
pg = anon->an_page;
/* page must be resident since parent is wired */
- if (pg == NULL)
- panic("amap_cow_now: non-resident wired page"
- " in anon %p", anon);
+ KASSERT(pg != NULL);
/*
* if the anon ref count is one, we are safe (the child
@@ -740,24 +737,23 @@ ReStart:
void
amap_splitref(struct vm_aref *origref, struct vm_aref *splitref, vaddr_t
offset)
{
+ struct vm_amap *amap = origref->ar_amap;
int leftslots;
AMAP_B2SLOT(leftslots, offset);
- if (leftslots == 0)
- panic("amap_splitref: split at zero offset");
+ KASSERT(leftslots != 0);
- /* now: we have a valid am_mapped array. */
- if (origref->ar_amap->am_nslot - origref->ar_pageoff - leftslots <= 0)
- panic("amap_splitref: map size check failed");
+ KASSERT(amap->am_nslot - origref->ar_pageoff - leftslots > 0);
#ifdef UVM_AMAP_PPREF
- /* establish ppref before we add a duplicate reference to the amap */
- if (origref->ar_amap->am_ppref == NULL)
- amap_pp_establish(origref->ar_amap);
+ /* Establish ppref before we add a duplicate reference to the amap. */
+ if (amap->am_ppref == NULL)
+ amap_pp_establish(amap);
#endif
- splitref->ar_amap = origref->ar_amap;
- splitref->ar_amap->am_ref++; /* not a share reference */
+ /* Note: not a share reference. */
+ amap->am_ref++;
+ splitref->ar_amap = amap;
splitref->ar_pageoff = origref->ar_pageoff + leftslots;
}
@@ -828,9 +824,7 @@ amap_pp_adjref(struct vm_amap *amap, int
* now adjust reference counts in range. merge the first
* changed entry with the last unchanged entry if possible.
*/
- if (lcv != curslot)
- panic("amap_pp_adjref: overshot target");
-
+ KASSERT(lcv == curslot);
for (/* lcv already set */; lcv < stopslot ; lcv += len) {
pp_getreflen(ppref, lcv, &ref, &len);
if (lcv + len > stopslot) { /* goes past end? */
@@ -840,8 +834,7 @@ amap_pp_adjref(struct vm_amap *amap, int
len = stopslot - lcv;
}
ref += adjval;
- if (ref < 0)
- panic("amap_pp_adjref: negative reference count");
+ KASSERT(ref >= 0);
if (lcv == prevlcv + prevlen && ref == prevref) {
pp_setreflen(ppref, prevlcv, ref, prevlen + len);
} else {
@@ -1104,20 +1097,17 @@ amap_add(struct vm_aref *aref, vaddr_t o
slot = UVM_AMAP_SLOTIDX(slot);
if (replace) {
- if (chunk->ac_anon[slot] == NULL)
- panic("amap_add: replacing null anon");
- if (chunk->ac_anon[slot]->an_page != NULL &&
- (amap->am_flags & AMAP_SHARED) != 0) {
- pmap_page_protect(chunk->ac_anon[slot]->an_page,
- PROT_NONE);
+ struct vm_anon *oanon = chunk->ac_anon[slot];
+
+ KASSERT(oanon != NULL);
+ if (oanon->an_page && (amap->am_flags & AMAP_SHARED) != 0) {
+ pmap_page_protect(oanon->an_page, PROT_NONE);
/*
* XXX: suppose page is supposed to be wired somewhere?
*/
}
} else { /* !replace */
- if (chunk->ac_anon[slot] != NULL)
- panic("amap_add: slot in use");
-
+ KASSERT(chunk->ac_anon[slot] == NULL);
chunk->ac_usedmap |= 1 << slot;
amap->am_nused++;
}
@@ -1140,12 +1130,10 @@ amap_unadd(struct vm_aref *aref, vaddr_t
slot += aref->ar_pageoff;
KASSERT(slot < amap->am_nslot);
chunk = amap_chunk_get(amap, slot, 0, PR_NOWAIT);
- if (chunk == NULL)
- panic("amap_unadd: chunk for slot %d not present", slot);
+ KASSERT(chunk != NULL);
slot = UVM_AMAP_SLOTIDX(slot);
- if (chunk->ac_anon[slot] == NULL)
- panic("amap_unadd: nothing there");
+ KASSERT(chunk->ac_anon[slot] != NULL);
chunk->ac_anon[slot] = NULL;
chunk->ac_usedmap &= ~(1 << slot);
