[PATCH v4 01/18] memfd: export memfd_get_seals()

memfd_get_seals() is used by iommufd during preservation to make sure
that he preserved memfd was sealed when it was mapped into iommufd.
Since iommufd can be built as a module, export memfd_get_seals() to
avoid linker error.

Cc: Hugh Dickins <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]

Acked-by: Pratyush Yadav (Google) <[email protected]>
Reviewed-by: Ankit Soni <[email protected]>
Signed-off-by: Samiullah Khawaja <[email protected]>
---
 mm/memfd.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mm/memfd.c b/mm/memfd.c
index abe13b291ddc..c489b55df3bb 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -6,6 +6,7 @@
  * use by hugetlbfs as well as tmpfs.
  */
 
+#include <linux/export.h>
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/pagemap.h>
@@ -309,12 +310,19 @@ int memfd_add_seals(struct file *file, unsigned int seals)
 	return error;
 }
 
+/**
+ * memfd_get_seals - Gets current seals on a memfd
+ * @file: struct file representing the memfd
+ *
+ * Returns seals if file is a memfd, otherwise returns -EINVAL
+ */
 int memfd_get_seals(struct file *file)
 {
 	unsigned int *seals = memfd_file_seals_ptr(file);
 
 	return seals ? *seals : -EINVAL;
 }
+EXPORT_SYMBOL_GPL(memfd_get_seals);
 
 long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
 {
-- 
2.55.0.679.g6767b8d81c-goog