Re: [PATCH][next] iavf: Replace one-element array with flexible-array member

From: Tony Nguyen
Date: Tue May 23 2023 - 14:19:27 EST


On 5/15/2023 5:44 PM, Gustavo A. R. Silva wrote:
One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in struct iavf_qvlist_info, and refactor the rest of the code,
accordingly.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/289
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/net/ethernet/intel/iavf/iavf_client.c | 2 +-
drivers/net/ethernet/intel/iavf/iavf_client.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_client.c b/drivers/net/ethernet/intel/iavf/iavf_client.c
index 93c903c02c64..782384b3aa38 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_client.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_client.c
@@ -470,7 +470,7 @@ static int iavf_client_setup_qvlist(struct iavf_info *ldev,
v_qvlist_info = (struct virtchnl_rdma_qvlist_info *)qvlist_info;
msg_size = struct_size(v_qvlist_info, qv_info,
- v_qvlist_info->num_vectors - 1);
+ v_qvlist_info->num_vectors);

The problem is this mirrors the virtchnl struct (virtchnl_rdma_qvlist_info) so that structure needs to change as well... However, this goes back to the interface that virtchnl provides between PF and VF [1].

I think removing the iavf structure and directly using the virtchnl one would make sense. We'd need to adjust virtchnl and follow Kees' suggestion [2].

adapter->client_pending |= BIT(VIRTCHNL_OP_CONFIG_RDMA_IRQ_MAP);
err = iavf_aq_send_msg_to_pf(&adapter->hw,
diff --git a/drivers/net/ethernet/intel/iavf/iavf_client.h b/drivers/net/ethernet/intel/iavf/iavf_client.h
index c5d51d7dc7cc..500269bc0f5b 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_client.h
+++ b/drivers/net/ethernet/intel/iavf/iavf_client.h
@@ -53,7 +53,7 @@ struct iavf_qv_info {
struct iavf_qvlist_info {
u32 num_vectors;
- struct iavf_qv_info qv_info[1];
+ struct iavf_qv_info qv_info[];
};
#define IAVF_CLIENT_MSIX_ALL 0xFFFFFFFF

[1] https://lore.kernel.org/intel-wired-lan/f3674339c0390ced22b365101f2d3e3a2bf26845.camel@xxxxxxxxx/
[2] https://lore.kernel.org/intel-wired-lan/202106091424.37E833794@keescook/