diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index d842ac4..6053f47 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -933,8 +933,8 @@
 static int erst_close_pstore(struct pstore_info *psi);
 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
 			   struct timespec *time, struct pstore_info *psi);
-static u64 erst_writer(enum pstore_type_id type, int part, size_t size,
-		       struct pstore_info *psi);
+static u64 erst_writer(enum pstore_type_id type, unsigned int part,
+		       size_t size, struct pstore_info *psi);
 static int erst_clearer(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);
 
@@ -1040,8 +1040,8 @@
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static u64 erst_writer(enum pstore_type_id type, int part, size_t size,
-		       struct pstore_info *psi)
+static u64 erst_writer(enum pstore_type_id type, unsigned int part,
+		       size_t size, struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
 					(erst_info.buf - sizeof(*rcd));