diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
index a16a04841b96..1654211cc6cf 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -419,6 +419,8 @@ option: ``huge=``. It can have following values:
 
 always
     Attempt to allocate huge pages every time we need a new page;
+    Always try PMD-sized huge pages first, and fall back to smaller-sized
+    huge pages if the PMD-sized huge page allocation fails;
 
 never
     Do not allocate huge pages. Note that ``madvise(..., MADV_COLLAPSE)``
@@ -426,7 +428,9 @@ never
     is specified everywhere;
 
 within_size
-    Only allocate huge page if it will be fully within i_size.
+    Only allocate huge page if it will be fully within i_size;
+    Always try PMD-sized huge pages first, and fall back to smaller-sized
+    huge pages if the PMD-sized huge page allocation fails;
     Also respect madvise() hints;
 
 advise
diff --git a/mm/shmem.c b/mm/shmem.c
index 2df26f4d6e60..29e1eb690125 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -573,42 +573,6 @@ static int shmem_confirm_swap(struct address_space *mapping, pgoff_t index,
 static int shmem_huge __read_mostly = SHMEM_HUGE_NEVER;
 static int tmpfs_huge __read_mostly = SHMEM_HUGE_NEVER;
 
-/**
- * shmem_mapping_size_orders - Get allowable folio orders for the given file size.
- * @mapping: Target address_space.
- * @index: The page index.
- * @write_end: end of a write, could extend inode size.
- *
- * This returns huge orders for folios (when supported) based on the file size
- * which the mapping currently allows at the given index. The index is relevant
- * due to alignment considerations the mapping might have. The returned order
- * may be less than the size passed.
- *
- * Return: The orders.
- */
-static inline unsigned int
-shmem_mapping_size_orders(struct address_space *mapping, pgoff_t index, loff_t write_end)
-{
-	unsigned int order;
-	size_t size;
-
-	if (!mapping_large_folio_support(mapping) || !write_end)
-		return 0;
-
-	/* Calculate the write size based on the write_end */
-	size = write_end - (index << PAGE_SHIFT);
-	order = filemap_get_order(size);
-	if (!order)
-		return 0;
-
-	/* If we're not aligned, allocate a smaller folio */
-	if (index & ((1UL << order) - 1))
-		order = __ffs(index);
-
-	order = min_t(size_t, order, MAX_PAGECACHE_ORDER);
-	return order > 0 ? BIT(order + 1) - 1 : 0;
-}
-
 static unsigned int shmem_get_orders_within_size(struct inode *inode,
 		unsigned long within_size_orders, pgoff_t index,
 		loff_t write_end)
@@ -655,22 +619,21 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index
 	 * For tmpfs mmap()'s huge order, we still use PMD-sized order to
 	 * allocate huge pages due to lack of a write size hint.
 	 *
-	 * Otherwise, tmpfs will allow getting a highest order hint based on
-	 * the size of write and fallocate paths, then will try each allowable
-	 * huge orders.
+	 * For tmpfs with 'huge=always' or 'huge=within_size' mount option,
+	 * we will always try PMD-sized order first. If that failed, it will
+	 * fall back to small large folios.
 	 */
 	switch (SHMEM_SB(inode->i_sb)->huge) {
 	case SHMEM_HUGE_ALWAYS:
 		if (vma)
 			return maybe_pmd_order;
 
-		return shmem_mapping_size_orders(inode->i_mapping, index, write_end);
+		return THP_ORDERS_ALL_FILE_DEFAULT;
 	case SHMEM_HUGE_WITHIN_SIZE:
 		if (vma)
 			within_size_orders = maybe_pmd_order;
 		else
-			within_size_orders = shmem_mapping_size_orders(inode->i_mapping,
-								       index, write_end);
+			within_size_orders = THP_ORDERS_ALL_FILE_DEFAULT;
 
 		within_size_orders = shmem_get_orders_within_size(inode, within_size_orders,
 								  index, write_end);