2021-05-25 23:10:16

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH][next] iavf: Replace one-element array in struct virtchnl_rss_lut

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_rss_lut instead of one-element array, and use the struct_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 <[email protected]>
---
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c | 5 ++---
include/linux/avf/virtchnl.h | 6 +++---
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
index 6f2a4c8beb0b..123a737f6955 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
@@ -830,7 +830,7 @@ void iavf_set_rss_key(struct iavf_adapter *adapter)
void iavf_set_rss_lut(struct iavf_adapter *adapter)
{
struct virtchnl_rss_lut *vrl;
- int len;
+ size_t len;

if (adapter->current_op != VIRTCHNL_OP_UNKNOWN) {
/* bail because we already have a command pending */
@@ -838,8 +838,7 @@ void iavf_set_rss_lut(struct iavf_adapter *adapter)
adapter->current_op);
return;
}
- len = sizeof(struct virtchnl_rss_lut) +
- (adapter->rss_lut_size * sizeof(u8)) - 1;
+ len = struct_size(vrl, lut, adapter->rss_lut_size);
vrl = kzalloc(len, GFP_KERNEL);
if (!vrl)
return;
diff --git a/include/linux/avf/virtchnl.h b/include/linux/avf/virtchnl.h
index d2fd847a3880..cda0c98ca978 100644
--- a/include/linux/avf/virtchnl.h
+++ b/include/linux/avf/virtchnl.h
@@ -492,10 +492,10 @@ VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_rss_key);
struct virtchnl_rss_lut {
u16 vsi_id;
u16 lut_entries;
- u8 lut[1]; /* RSS lookup table */
+ u8 lut[]; /* RSS lookup table */
};

-VIRTCHNL_CHECK_STRUCT_LEN(6, virtchnl_rss_lut);
+VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_rss_lut);

/* VIRTCHNL_OP_GET_RSS_HENA_CAPS
* VIRTCHNL_OP_SET_RSS_HENA
@@ -1087,7 +1087,7 @@ virtchnl_vc_validate_vf_msg(struct virtchnl_version_info *ver, u32 v_opcode,
if (msglen >= valid_len) {
struct virtchnl_rss_lut *vrl =
(struct virtchnl_rss_lut *)msg;
- valid_len += vrl->lut_entries - 1;
+ valid_len += vrl->lut_entries;
}
break;
case VIRTCHNL_OP_GET_RSS_HENA_CAPS:
--
2.27.0