pstore: Pass header size in the pstore write callback

Header size is needed to distinguish between header and the dump data.
Incorporate the addition of new argument (hsize) in the pstore write
callback.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/acpi/apei/erst.c

@@ -935,7 +935,7 @@ static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 			   struct timespec *time, char **buf,
 			   struct pstore_info *psi);
 static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
-		       u64 *id, unsigned int part, int count,
+		       u64 *id, unsigned int part, int count, size_t hsize,
 		       size_t size, struct pstore_info *psi);
 static int erst_clearer(enum pstore_type_id type, u64 id, int count,
 			struct timespec time, struct pstore_info *psi);
@@ -1055,7 +1055,7 @@ out:
 }
 
 static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
-		       u64 *id, unsigned int part, int count,
+		       u64 *id, unsigned int part, int count, size_t hsize,
 		       size_t size, struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)