khugepaged: inline hpage_collapse_alloc_folio()

Patch series "khugepaged folio conversions".

We've been kind of hacking piecemeal at converting khugepaged to use
folios instead of compound pages, and so this patchset is a little larger
than it should be as I undo some of our wrong moves in the past.  In
particular, collapse_file() now consistently uses 'new_folio' for the
freshly allocated folio and 'folio' for the one that's currently in use.  


This patch (of 7):

This function has one caller, and the combined function is simpler to
read, reason about and modify.

Link: https://lkml.kernel.org/r/20240403171838.1445826-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240403171838.1445826-2-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> 
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged.c

@@ -891,20 +891,6 @@ static int hpage_collapse_find_target_node(struct collapse_control *cc)
 }
 #endif
 
-static bool hpage_collapse_alloc_folio(struct folio **folio, gfp_t gfp, int node,
-				      nodemask_t *nmask)
-{
-	*folio = __folio_alloc(gfp, HPAGE_PMD_ORDER, node, nmask);
-
-	if (unlikely(!*folio)) {
-		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
-		return false;
-	}
-
-	count_vm_event(THP_COLLAPSE_ALLOC);
-	return true;
-}
-
 /*
  * If mmap_lock temporarily dropped, revalidate vma
  * before taking mmap_lock.
@@ -1067,11 +1053,14 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm,
 	int node = hpage_collapse_find_target_node(cc);
 	struct folio *folio;
 
-	if (!hpage_collapse_alloc_folio(&folio, gfp, node, &cc->alloc_nmask)) {
+	folio = __folio_alloc(gfp, HPAGE_PMD_ORDER, node, &cc->alloc_nmask);
+	if (!folio) {
 		*hpage = NULL;
+		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
 		return SCAN_ALLOC_HUGE_PAGE_FAIL;
 	}
 
+	count_vm_event(THP_COLLAPSE_ALLOC);
 	if (unlikely(mem_cgroup_charge(folio, mm, gfp))) {
 		folio_put(folio);
 		*hpage = NULL;