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mm/memory.c: use folios in __access_remote_vm()

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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().

Link: https://lkml.kernel.org/r/20250709194017.927978-5-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: 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>
This commit is contained in:
Vishal Moola (Oracle) 2025-07-09 12:40:17 -07:00 committed by Andrew Morton
parent 0ec5eea208
commit 0c092fef53
1 changed files with 5 additions and 3 deletions
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8
mm/memory.c
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@ -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;