linux-kernel - [PATCH v3 3/4] mm/memory: convert do_shared

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Date:   Thu,  6 Jul 2023 09:38:46 -0700
From:   Sidhartha Kumar <sidhartha.kumar@...cle.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     akpm@...ux-foundation.org, willy@...radead.org,
        zhangpeng362@...wei.com,
        Sidhartha Kumar <sidhartha.kumar@...cle.com>
Subject: [PATCH v3 3/4] mm/memory: convert do_shared_fault() to folios

Saves three implicit calls to compound_head().

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@...cle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
v2:
	 - move folio initialization after __do_fault()
 mm/memory.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 673b9fa67d0d7..a59b10e534c07 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4607,21 +4607,24 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	vm_fault_t ret, tmp;
+	struct folio *folio;
 
 	ret = __do_fault(vmf);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;
 
+	folio = page_folio(vmf->page);
+
 	/*
 	 * Check if the backing address space wants to know that the page is
 	 * about to become writable
 	 */
 	if (vma->vm_ops->page_mkwrite) {
-		unlock_page(vmf->page);
+		folio_unlock(folio);
 		tmp = do_page_mkwrite(vmf);
 		if (unlikely(!tmp ||
 				(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
-			put_page(vmf->page);
+			folio_put(folio);
 			return tmp;
 		}
 	}
@@ -4629,8 +4632,8 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf)
 	ret |= finish_fault(vmf);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
 					VM_FAULT_RETRY))) {
-		unlock_page(vmf->page);
-		put_page(vmf->page);
+		folio_unlock(folio);
+		folio_put(folio);
 		return ret;
 	}
 
-- 
2.41.0