iov_iter: convert iov_iter_extract_xarray_pages() to use folios

ITER_XARRAY is exclusively used with xarrays that contain folios, not
pages, so extract folio pointers from it, not page pointers.  Removes a
use of find_subpage().

Link: https://lkml.kernel.org/r/20250402210612.2444135-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 3e340d1..d9e19fb 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1650,11 +1650,11 @@ static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i,
                                             iov_iter_extraction_t extraction_flags,
                                             size_t *offset0)
 {
-       struct page *page, **p;
+       struct page **p;
+       struct folio *folio;
        unsigned int nr = 0, offset;
        loff_t pos = i->xarray_start + i->iov_offset;
-       pgoff_t index = pos >> PAGE_SHIFT;
-       XA_STATE(xas, i->xarray, index);
+       XA_STATE(xas, i->xarray, pos >> PAGE_SHIFT);
 
        offset = pos & ~PAGE_MASK;
        *offset0 = offset;
@@ -1665,17 +1665,17 @@ static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i,
        p = *pages;
 
        rcu_read_lock();
-       for (page = xas_load(&xas); page; page = xas_next(&xas)) {
-               if (xas_retry(&xas, page))
+       for (folio = xas_load(&xas); folio; folio = xas_next(&xas)) {
+               if (xas_retry(&xas, folio))
                        continue;
 
-               /* Has the page moved or been split? */
-               if (unlikely(page != xas_reload(&xas))) {
+               /* Has the folio moved or been split? */
+               if (unlikely(folio != xas_reload(&xas))) {
                        xas_reset(&xas);
                        continue;
                }
 
-               p[nr++] = find_subpage(page, xas.xa_index);
+               p[nr++] = folio_file_page(folio, xas.xa_index);
                if (nr == maxpages)
                        break;
        }