linux-kernel - [PATCH 2/3] mm/memory.c: Use folios in __access_remote

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Message-ID: <20250709194017.927978-5-vishal.moola@gmail.com>
Date: Wed,  9 Jul 2025 12:40:17 -0700
From: "Vishal Moola (Oracle)" <vishal.moola@...il.com>
To: linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	David Hildenbrand <david@...hat.com>,
	Jordan Rome <linux@...danrome.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Vishal Moola (Oracle)" <vishal.moola@...il.com>
Subject: [PATCH 2/3] mm/memory.c: Use folios in __access_remote_vm()

Use kmap_local_folio() instead of kmap_local_page().
Replaces 2 calls to compound_head() with one.

This prepares us for the removal of unmap_and_put_page().

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@...il.com>
---
 mm/memory.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index d63f0d5abcc9..3dd6c57e6511 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6691,6 +6691,7 @@ static int __access_remote_vm(struct mm_struct *mm, unsigned long addr,
 	while (len) {
 		int bytes, offset;
 		void *maddr;
+		struct folio *folio;
 		struct vm_area_struct *vma = NULL;
 		struct page *page = get_user_page_vma_remote(mm, addr,
 							     gup_flags, &vma);
@@ -6722,21 +6723,22 @@ static int __access_remote_vm(struct mm_struct *mm, unsigned long addr,
 			if (bytes <= 0)
 				break;
 		} else {
+			folio = page_folio(page);
 			bytes = len;
 			offset = addr & (PAGE_SIZE-1);
 			if (bytes > PAGE_SIZE-offset)
 				bytes = PAGE_SIZE-offset;
 
-			maddr = kmap_local_page(page);
+			maddr = kmap_local_folio(folio, folio_page_idx(folio, page) * PAGE_SIZE);
 			if (write) {
 				copy_to_user_page(vma, page, addr,
 						  maddr + offset, buf, bytes);
-				set_page_dirty_lock(page);
+				folio_mark_dirty_lock(folio);
 			} else {
 				copy_from_user_page(vma, page, addr,
 						    buf, maddr + offset, bytes);
 			}
-			unmap_and_put_page(page, maddr);
+			folio_release_kmap(folio, maddr);
 		}
 		len -= bytes;
 		buf += bytes;
-- 
2.50.0