On configs where MAP_DROPPABLE is not supported (currently any 32-bit
config except for PPC32), mmap fails with errno set to ENOTSUPP.
However, ENOTSUPP is not a standard error value that userspace knows
about. The acceptable userspace-visible errno to use is EOPNOTSUPP.
checkpatch.pl has a warning to this effect.

Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings")
Cc: <stable@vger.kernel.org>
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: David Hildenbrand <david@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reported-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
---
 mm/mmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 5754d1c36462..2311ae7c2ff4 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -504,7 +504,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
 			break;
 		case MAP_DROPPABLE:
 			if (VM_DROPPABLE == VM_NONE)
-				return -ENOTSUPP;
+				return -EOPNOTSUPP;
 			/*
 			 * A locked or stack area makes no sense to be droppable.
 			 *
-- 
2.47.3