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

[David Hildenbrand]

On 28.04.25 22:23, Lorenzo Stoakes wrote:
> On Fri, Apr 25, 2025 at 10:17:13AM +0200, David Hildenbrand wrote:
>> The "memramp() shrinking" scenario no longer applies, so let's remove
>> that now-unnecessary handling.
> 
> I wonder if we could remove even more of the code here given the
> simplifications here? But not a big deal.

It might make sense to inline memtype_match().

diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
index 9d03f0dbc4715..e5844ed1311ed 100644
--- a/arch/x86/mm/pat/memtype_interval.c
+++ b/arch/x86/mm/pat/memtype_interval.c
@@ -49,21 +49,6 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
  
  static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
  
-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 (entry_match->start == start && entry_match->end == end)
-                       return entry_match;
-               entry_match = interval_iter_next(entry_match, start, end-1);
-       }
-
-       return NULL; /* Returns NULL if there is no match */
-}
-
  static int memtype_check_conflict(u64 start, u64 end,
                                   enum page_cache_mode reqtype,
                                   enum page_cache_mode *newtype)
@@ -119,14 +104,16 @@ int memtype_check_insert(struct memtype *entry_new, enum page_cache_mode *ret_ty
  
  struct memtype *memtype_erase(u64 start, u64 end)
  {
-       struct memtype *entry_old;
-
-       entry_old = memtype_match(start, end);
-       if (!entry_old)
-               return ERR_PTR(-EINVAL);
-
-       interval_remove(entry_old, &memtype_rbroot);
-       return entry_old;
+       struct memtype *entry = interval_iter_first(&memtype_rbroot, start, end - 1);
+
+       while (entry && entry->start < end) {
+               if (entry->start == start && entry->end == end) {
+                       interval_remove(entry, &memtype_rbroot);
+                       return entry;
+               }
+               entry = interval_iter_next(entry, start, end - 1);
+       }
+       return ERR_PTR(-EINVAL);
  }
  
  struct memtype *memtype_lookup(u64 addr)


Thanks for all the review!

-- 
Cheers,

David / dhildenb