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From:   Sidhartha Kumar <sidhartha.kumar@oracle.com>
To:     linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc:     akpm@linux-foundation.org, willy@infradead.org,
        Sidhartha Kumar <sidhartha.kumar@oracle.com>
Subject: [PATCH] mm/memory: pass folio into do_page_mkwrite()
Date:   Mon, 10 Jul 2023 22:35:44 -0700
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Saves one implicit call to compound_head().

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
I'm not sure if I should change the name of the function
to do_folio_mkwrite() and update the description comment
to reference a folio as the vm_op is still called page_mkwrite.

 mm/memory.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 1dada20e39959..ad790394963ab 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2936,10 +2936,9 @@ static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma)
  *
  * We do this without the lock held, so that it can sleep if it needs to.
  */
-static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
+static vm_fault_t do_page_mkwrite(struct vm_fault *vmf, struct folio *folio)
 {
 	vm_fault_t ret;
-	struct folio *folio = page_folio(vmf->page);
 	unsigned int old_flags = vmf->flags;
 
 	vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
@@ -3301,7 +3300,7 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)
 		vm_fault_t tmp;
 
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
-		tmp = do_page_mkwrite(vmf);
+		tmp = do_page_mkwrite(vmf, folio);
 		if (unlikely(!tmp || (tmp &
 				      (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
 			folio_put(folio);
@@ -4627,7 +4626,7 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf)
 	 */
 	if (vma->vm_ops->page_mkwrite) {
 		folio_unlock(folio);
-		tmp = do_page_mkwrite(vmf);
+		tmp = do_page_mkwrite(vmf, folio);
 		if (unlikely(!tmp ||
 				(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
 			folio_put(folio);
-- 
2.41.0