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().

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

diff --git a/mm/memory.c b/mm/memory.c
index 1174f3001307..d63f0d5abcc9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6815,6 +6815,7 @@ static int __copy_remote_vm_str(struct mm_struct *mm, unsigned long addr,
 	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 mm_struct *mm, unsigned long addr,
 			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 mm_struct *mm, unsigned long addr,
 		}
 		len -= bytes;
 
-		unmap_and_put_page(page, maddr);
+		folio_release_kmap(folio, maddr);
 	}
 
 out:
-- 
2.50.0

On 09.07.25 21:40, Vishal Moola (Oracle) wrote:
> 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().
> 
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> ---
>   mm/memory.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 1174f3001307..d63f0d5abcc9 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -6815,6 +6815,7 @@ static int __copy_remote_vm_str(struct mm_struct *mm, unsigned long addr,
>   	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 mm_struct *mm, unsigned long addr,
>   			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);

It's weird to go page -> folio -> page ... but maybe that's just the way 
it's supposed to work here ...

:)

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb