[PATCH][next] media: venus: hfi_cmds.h: Replace one-element array with flexible-array member

From: Gustavo A. R. Silva
Date: Wed Feb 10 2021 - 17:58:17 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].

Use flexible-array member in struct hfi_sys_set_property_pkt instead of
one-element array.

Also, this helps with the ongoing efforts to enable -Warray-bounds and
fix the following warnings:

drivers/media/platform/qcom/venus/hfi_cmds.c: In function ‘pkt_sys_coverage_config’:
drivers/media/platform/qcom/venus/hfi_cmds.c:57:11: warning: array subscript 1 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
57 | pkt->data[1] = mode;
| ~~~~~~~~~^~~

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/109
Build-tested-by: kernel test robot <lkp@xxxxxxxxx>
Link: https://lore.kernel.org/lkml/602416da.iZqae7Dbk7nyl6OY%25lkp@xxxxxxxxx/
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/media/platform/qcom/venus/hfi_cmds.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/qcom/venus/hfi_cmds.h b/drivers/media/platform/qcom/venus/hfi_cmds.h
index 83705e237f1c..327ed90a2788 100644
--- a/drivers/media/platform/qcom/venus/hfi_cmds.h
+++ b/drivers/media/platform/qcom/venus/hfi_cmds.h
@@ -68,7 +68,7 @@ struct hfi_sys_release_resource_pkt {
struct hfi_sys_set_property_pkt {
struct hfi_pkt_hdr hdr;
u32 num_properties;
- u32 data[1];
+ u32 data[];
};

struct hfi_sys_get_property_pkt {
--
2.27.0