[PATCH 10/12] shmem: add order arg to shmem_alloc_folio()

[Daniel Gomez <da.gomez@xxxxxxxxxxx>]

Add folio order argument to the shmem_alloc_folio(). Return will make
use of the new page_rmappable_folio() where order-0 and high order
folios are both supported.

As the order requested may not match the order returned when allocating
high order folios, make sure pages are calculated after getting the
folio.

Signed-off-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>
---
 mm/shmem.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 7a6ad678e2ff..d531018ffece 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1828,18 +1828,18 @@ static struct folio *shmem_alloc_hugefolio(gfp_t gfp,
 	return page_rmappable_folio(page);
 }
 
-static struct folio *shmem_alloc_folio(gfp_t gfp,
-		struct shmem_inode_info *info, pgoff_t index)
+static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info,
+				       pgoff_t index, unsigned int order)
 {
 	struct mempolicy *mpol;
 	pgoff_t ilx;
 	struct page *page;
 
-	mpol = shmem_get_pgoff_policy(info, index, 0, &ilx);
-	page = alloc_pages_mpol(gfp, 0, mpol, ilx, numa_node_id());
+	mpol = shmem_get_pgoff_policy(info, index, order, &ilx);
+	page = alloc_pages_mpol(gfp, order, mpol, ilx, numa_node_id());
 	mpol_cond_put(mpol);
 
-	return (struct folio *)page;
+	return page_rmappable_folio(page);
 }
 
 static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
@@ -1848,6 +1848,7 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
 {
 	struct address_space *mapping = inode->i_mapping;
 	struct shmem_inode_info *info = SHMEM_I(inode);
+	unsigned int order = 0;
 	struct folio *folio;
 	long pages;
 	int error;
@@ -1856,7 +1857,6 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
 		huge = false;
 
 	if (huge) {
-		pages = HPAGE_PMD_NR;
 		index = round_down(index, HPAGE_PMD_NR);
 
 		/*
@@ -1875,12 +1875,13 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
 		if (!folio)
 			count_vm_event(THP_FILE_FALLBACK);
 	} else {
-		pages = 1;
-		folio = shmem_alloc_folio(gfp, info, index);
+		folio = shmem_alloc_folio(gfp, info, index, order);
 	}
 	if (!folio)
 		return ERR_PTR(-ENOMEM);
 
+	pages = folio_nr_pages(folio);
+
 	__folio_set_locked(folio);
 	__folio_set_swapbacked(folio);
 
@@ -1976,7 +1977,7 @@ static int shmem_replace_folio(struct folio **foliop, gfp_t gfp,
 	 */
 	gfp &= ~GFP_CONSTRAINT_MASK;
 	VM_BUG_ON_FOLIO(folio_test_large(old), old);
-	new = shmem_alloc_folio(gfp, info, index);
+	new = shmem_alloc_folio(gfp, info, index, folio_order(old));
 	if (!new)
 		return -ENOMEM;
 
@@ -2855,7 +2856,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
 
 	if (!*foliop) {
 		ret = -ENOMEM;
-		folio = shmem_alloc_folio(gfp, info, pgoff);
+		folio = shmem_alloc_folio(gfp, info, pgoff, 0);
 		if (!folio)
 			goto out_unacct_blocks;
 
-- 
2.43.0