scsi: smartpqi: Replace one-element arrays with flexible-array members

One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element arrays with flexible-array
members in a couple of structures, and refactor the rest of the code,
accordingly.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines
on memcpy().

This results in no differences in binary output.

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/204
Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Link: https://lore.kernel.org/r/ZJNdKDkuRbFZpASS@work
Reviewed-by: Kees Cook <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/smartpqi/smartpqi.h

···
 
 struct report_phys_lun_8byte_wwid_list {
 	struct report_lun_header header;
-	struct report_phys_lun_8byte_wwid lun_entries[1];
+	struct report_phys_lun_8byte_wwid lun_entries[];
 };
 
 struct report_phys_lun_16byte_wwid_list {
 	struct report_lun_header header;
-	struct report_phys_lun_16byte_wwid lun_entries[1];
+	struct report_phys_lun_16byte_wwid lun_entries[];
 };
 
 struct raid_map_disk_data {

drivers/scsi/smartpqi/smartpqi_init.c

···
 	unsigned int i;
 	u8 rpl_response_format;
 	u32 num_physicals;
-	size_t rpl_16byte_wwid_list_length;
 	void *rpl_list;
 	struct report_lun_header *rpl_header;
 	struct report_phys_lun_8byte_wwid_list *rpl_8byte_wwid_list;
···
 
 	rpl_8byte_wwid_list = rpl_list;
 	num_physicals = get_unaligned_be32(&rpl_8byte_wwid_list->header.list_length) / sizeof(rpl_8byte_wwid_list->lun_entries[0]);
-	rpl_16byte_wwid_list_length = sizeof(struct report_lun_header) + (num_physicals * sizeof(struct report_phys_lun_16byte_wwid));
 
-	rpl_16byte_wwid_list = kmalloc(rpl_16byte_wwid_list_length, GFP_KERNEL);
+	rpl_16byte_wwid_list = kmalloc(struct_size(rpl_16byte_wwid_list, lun_entries,
+						   num_physicals), GFP_KERNEL);
 	if (!rpl_16byte_wwid_list)
 		return -ENOMEM;