[PATCH][next] virtchnl: Replace one-element array in struct virtchnl_vsi_queue_config_info

From: Gustavo A. R. Silva
Date: Tue May 25 2021 - 19:16:05 EST


There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Refactor the code according to the use of a flexible-array member in struct
virtchnl_vsi_queue_config_info instead of one-element array, and use the
flex_array_size() helper.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
include/linux/avf/virtchnl.h | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/include/linux/avf/virtchnl.h b/include/linux/avf/virtchnl.h
index b554913804bd..ed9c4998f8ac 100644
--- a/include/linux/avf/virtchnl.h
+++ b/include/linux/avf/virtchnl.h
@@ -338,10 +338,10 @@ struct virtchnl_vsi_queue_config_info {
u16 vsi_id;
u16 num_queue_pairs;
u32 pad;
- struct virtchnl_queue_pair_info qpair[1];
+ struct virtchnl_queue_pair_info qpair[];
};

-VIRTCHNL_CHECK_STRUCT_LEN(72, virtchnl_vsi_queue_config_info);
+VIRTCHNL_CHECK_STRUCT_LEN(8, virtchnl_vsi_queue_config_info);

/* VIRTCHNL_OP_REQUEST_QUEUES
* VF sends this message to request the PF to allocate additional queues to
@@ -997,9 +997,8 @@ virtchnl_vc_validate_vf_msg(struct virtchnl_version_info *ver, u32 v_opcode,
if (msglen >= valid_len) {
struct virtchnl_vsi_queue_config_info *vqc =
(struct virtchnl_vsi_queue_config_info *)msg;
- valid_len += (vqc->num_queue_pairs *
- sizeof(struct
- virtchnl_queue_pair_info));
+ valid_len += flex_array_size(vqc, qpair,
+ vqc->num_queue_pairs);
if (vqc->num_queue_pairs == 0)
err_msg_format = true;
}
--
2.27.0