[PATCH v1 09/11] x86/mm/pat: remove MEMTYPE_*_MATCH

David Hildenbrand
2025-04-25T08:17:50Z

The "memramp() shrinking" scenario no longer applies, so let's remove
that now-unnecessary handling.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
1 file changed, 6 insertions(+), 38 deletions(-)

diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
index 645613d59942a..9d03f0dbc4715 100644
--- a/arch/x86/mm/pat/memtype_interval.c
+++ b/arch/x86/mm/pat/memtype_interval.c
@@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,

static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;

-enum {
- MEMTYPE_EXACT_MATCH = 0,
- MEMTYPE_END_MATCH = 1
-};
-
-static struct memtype *memtype_match(u64 start, u64 end, int match_type)
+static struct memtype *memtype_match(u64 start, u64 end)
{
struct memtype *entry_match;

entry_match = interval_iter_first(&memtype_rbroot, start, end-1);

while (entry_match != NULL && entry_match->start < end) {
- if ((match_type == MEMTYPE_EXACT_MATCH) &&
- (entry_match->start == start) && (entry_match->end == end))
- return entry_match;
-
- if ((match_type == MEMTYPE_END_MATCH) &&
- (entry_match->start < start) && (entry_match->end == end))
+ if (entry_match->start == start && entry_match->end == end)
return entry_match;
-
entry_match = interval_iter_next(entry_match, start, end-1);
}

@@ -132,32 +121,11 @@ struct memtype *memtype_erase(u64 start, u64 end)
{
struct memtype *entry_old;

- /*
- * Since the memtype_rbroot tree allows overlapping ranges,
- * memtype_erase() checks with EXACT_MATCH first, i.e. free
- * a whole node for the munmap case. If no such entry is found,
- * it then checks with END_MATCH, i.e. shrink the size of a node
- * from the end for the mremap case.
- */
- entry_old = memtype_match(start, end, MEMTYPE_EXACT_MATCH);
- if (!entry_old) {
- entry_old = memtype_match(start, end, MEMTYPE_END_MATCH);
- if (!entry_old)
- return ERR_PTR(-EINVAL);
- }
-
- if (entry_old->start == start) {
- /* munmap: erase this node */
- interval_remove(entry_old, &memtype_rbroot);
- } else {
- /* mremap: update the end value of this node */
- interval_remove(entry_old, &memtype_rbroot);
- entry_old->end = start;
- interval_insert(entry_old, &memtype_rbroot);
-
- return NULL;
- }
+ entry_old = memtype_match(start, end);
+ if (!entry_old)
+ return ERR_PTR(-EINVAL);

+ interval_remove(entry_old, &memtype_rbroot);
return entry_old;
}

--
2.49.0