[PATCH v3][next] scsi: lpfc: Use struct_size() helper

[Justin Tee <justintee8345@gmail.com>]

Prefer struct_size() over open-coded versions of idiom:

sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count

where count is the max number of items the flexible array is supposed to
contain.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
---
Changes in v3:
 - Instead of hardcode to 1, use be32_to_cpu(rap->no_of_objects).
   (Justin Tee).

v2:
 - Use literal 1 in call to struct_size(), instead of rap->no_of_objects
   (Kees Cook).

v1:
 - Link:
   https://lore.kernel.org/linux-hardening/99e06733f5f35c6cd62e05f530b93107bfd03362.1684358315.git.gustavoars@kernel.org/
---
 drivers/scsi/lpfc/lpfc_ct.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_ct.c b/drivers/scsi/lpfc/lpfc_ct.c
index e880d127d7f5..703429512ead 100644
--- a/drivers/scsi/lpfc/lpfc_ct.c
+++ b/drivers/scsi/lpfc/lpfc_ct.c
@@ -3748,8 +3748,7 @@ lpfc_vmid_cmd(struct lpfc_vport *vport,
 		rap->obj[0].entity_id_len = vmid->vmid_len;
 		memcpy(rap->obj[0].entity_id, vmid->host_vmid, vmid->vmid_len);
 		size = RAPP_IDENT_OFFSET +
-			sizeof(struct lpfc_vmid_rapp_ident_list) +
-			sizeof(struct entity_id_object);
+		       struct_size(rap, obj, be32_to_cpu(rap->no_of_objects));
 		retry = 1;
 		break;
 
@@ -3768,8 +3767,7 @@ lpfc_vmid_cmd(struct lpfc_vport *vport,
 		dap->obj[0].entity_id_len = vmid->vmid_len;
 		memcpy(dap->obj[0].entity_id, vmid->host_vmid, vmid->vmid_len);
 		size = DAPP_IDENT_OFFSET +
-			sizeof(struct lpfc_vmid_dapp_ident_list) +
-			sizeof(struct entity_id_object);
+		       struct_size(dap, obj, be32_to_cpu(dap->no_of_objects));
 		write_lock(&vport->vmid_lock);
 		vmid->flag &= ~LPFC_VMID_REGISTERED;
 		write_unlock(&vport->vmid_lock);
-- 
2.38.0