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media: venus: hfi_msgs.h: Replace zero-length array with flexible-array member

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The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Gustavo A. R. Silva 2020-03-19 23:22:29 +01:00 committed by Mauro Carvalho Chehab
parent 380f3bbd95
commit 0f61e171e4
1 changed files with 5 additions and 5 deletions
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10
drivers/media/platform/qcom/venus/hfi_msgs.h
View file

@ -155,7 +155,7 @@ struct hfi_msg_session_empty_buffer_done_pkt {
u32 input_tag;
u32 packet_buffer;
u32 extradata_buffer;
u32 data[0];
u32 data[];
};
struct hfi_msg_session_fbd_compressed_pkt {
@ -175,7 +175,7 @@ struct hfi_msg_session_fbd_compressed_pkt {
u32 picture_type;
u32 packet_buffer;
u32 extradata_buffer;
u32 data[0];
u32 data[];
};
struct hfi_msg_session_fbd_uncompressed_plane0_pkt {
@ -202,7 +202,7 @@ struct hfi_msg_session_fbd_uncompressed_plane0_pkt {
u32 picture_type;
u32 packet_buffer;
u32 extradata_buffer;
u32 data[0];
u32 data[];
};
struct hfi_msg_session_fbd_uncompressed_plane1_pkt {
@ -211,7 +211,7 @@ struct hfi_msg_session_fbd_uncompressed_plane1_pkt {
u32 filled_len;
u32 offset;
u32 packet_buffer2;
u32 data[0];
u32 data[];
};
struct hfi_msg_session_fbd_uncompressed_plane2_pkt {
@ -220,7 +220,7 @@ struct hfi_msg_session_fbd_uncompressed_plane2_pkt {
u32 filled_len;
u32 offset;
u32 packet_buffer3;
u32 data[0];
u32 data[];
};
struct hfi_msg_session_parse_sequence_header_done_pkt {