+ mm-memoryc-use-folios-in-__copy_remote_vm_str.patch added to mm-new branch

+ mm-memoryc-use-folios-in-__copy_remote_vm_str.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/memory.c: use folios in __copy_remote_vm_str()
has been added to the -mm mm-new branch.  Its filename is
     mm-memoryc-use-folios-in-__copy_remote_vm_str.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memoryc-use-folios-in-__copy_remote_vm_str.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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------------------------------------------------------
From: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Subject: mm/memory.c: use folios in __copy_remote_vm_str()
Date: Wed, 9 Jul 2025 12:40:16 -0700

Patch series "Remove unmap_and_put_page()".

This patchset uses folios in both the callers of unmap_and_put_page(),
saving a couple calls to compound_head() wrappers.


This patch (of 3):

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

This prepares us for the removal of unmap_and_put_page().

Link: https://lkml.kernel.org/r/20250709194017.927978-3-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20250709194017.927978-4-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jordan Rome <linux@jordanrome.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/mm/memory.c~mm-memoryc-use-folios-in-__copy_remote_vm_str
+++ a/mm/memory.c
@@ -6815,6 +6815,7 @@ static int __copy_remote_vm_str(struct m
 	while (len) {
 		int bytes, offset, retval;
 		void *maddr;
+		struct folio *folio;
 		struct page *page;
 		struct vm_area_struct *vma = NULL;
 
@@ -6830,17 +6831,18 @@ static int __copy_remote_vm_str(struct m
 			goto out;
 		}
 
+		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);
 		retval = strscpy(buf, maddr + offset, bytes);
 		if (retval >= 0) {
 			/* Found the end of the string */
 			buf += retval;
-			unmap_and_put_page(page, maddr);
+			folio_release_kmap(folio, maddr);
 			break;
 		}
 
@@ -6858,7 +6860,7 @@ static int __copy_remote_vm_str(struct m
 		}
 		len -= bytes;
 
-		unmap_and_put_page(page, maddr);
+		folio_release_kmap(folio, maddr);
 	}
 
 out:
_

Patches currently in -mm which might be from vishal.moola@gmail.com are

mm-memoryc-use-folios-in-__copy_remote_vm_str.patch
mm-memoryc-use-folios-in-__access_remote_vm.patch
mm-remove-unmap_and_put_page.patch