uprobes: use folios more widely in __replace_page()

Remove a few hidden calls to compound_head().

Link: https://lkml.kernel.org/r/20220902194653.1739778-45-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/events/uprobes.c

@@ -19,7 +19,7 @@
 #include <linux/export.h>
 #include <linux/rmap.h>		/* anon_vma_prepare */
 #include <linux/mmu_notifier.h>	/* set_pte_at_notify */
-#include <linux/swap.h>		/* try_to_free_swap */
+#include <linux/swap.h>		/* folio_free_swap */
 #include <linux/ptrace.h>	/* user_enable_single_step */
 #include <linux/kdebug.h>	/* notifier mechanism */
 #include "../../mm/internal.h"	/* munlock_vma_page */
@@ -154,8 +154,9 @@ static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr)
 static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 				struct page *old_page, struct page *new_page)
 {
+	struct folio *old_folio = page_folio(old_page);
 	struct mm_struct *mm = vma->vm_mm;
-	DEFINE_FOLIO_VMA_WALK(pvmw, page_folio(old_page), vma, addr, 0);
+	DEFINE_FOLIO_VMA_WALK(pvmw, old_folio, vma, addr, 0);
 	int err;
 	struct mmu_notifier_range range;
 
@@ -169,8 +170,8 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 			return err;
 	}
 
-	/* For try_to_free_swap() below */
-	lock_page(old_page);
+	/* For folio_free_swap() below */
+	folio_lock(old_folio);
 
 	mmu_notifier_invalidate_range_start(&range);
 	err = -EAGAIN;
@@ -186,7 +187,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 		/* no new page, just dec_mm_counter for old_page */
 		dec_mm_counter(mm, MM_ANONPAGES);
 
-	if (!PageAnon(old_page)) {
+	if (!folio_test_anon(old_folio)) {
 		dec_mm_counter(mm, mm_counter_file(old_page));
 		inc_mm_counter(mm, MM_ANONPAGES);
 	}
@@ -198,15 +199,15 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 				  mk_pte(new_page, vma->vm_page_prot));
 
 	page_remove_rmap(old_page, vma, false);
-	if (!page_mapped(old_page))
-		try_to_free_swap(old_page);
+	if (!folio_mapped(old_folio))
+		folio_free_swap(old_folio);
 	page_vma_mapped_walk_done(&pvmw);
-	put_page(old_page);
+	folio_put(old_folio);
 
 	err = 0;
  unlock:
 	mmu_notifier_invalidate_range_end(&range);
-	unlock_page(old_page);
+	folio_unlock(old_folio);
 	return err;
 }