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Subject[PATCH][next] mei: Avoid the use of one-element arrays
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 or, as in this particular case, replace the one-element array
with a simple value type u8 reserved once this is just a placeholder
for alignment. The older style of one-element or zero-length arrays
should no longer be used[2].

Also, while there, use the preferred form for passing a size of a struct.
The alternative form where struct name is spelled out hurts readability
and introduces an opportunity for a bug when the variable type is changed
but the corresponding sizeof that is passed as argument is not.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/79

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
drivers/misc/mei/hbm.c | 4 ++--
drivers/misc/mei/hw.h | 6 +++---
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index a44094cdbc36..f020d5594154 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -408,14 +408,14 @@ static int mei_hbm_add_cl_resp(struct mei_device *dev, u8 addr, u8 status)
{
struct mei_msg_hdr mei_hdr;
struct hbm_add_client_response resp;
- const size_t len = sizeof(struct hbm_add_client_response);
+ const size_t len = sizeof(resp);
int ret;

dev_dbg(dev->dev, "adding client response\n");

mei_hbm_hdr(&mei_hdr, len);

- memset(&resp, 0, sizeof(struct hbm_add_client_response));
+ memset(&resp, 0, len);
resp.hbm_cmd = MEI_HBM_ADD_CLIENT_RES_CMD;
resp.me_addr = addr;
resp.status = status;
diff --git a/drivers/misc/mei/hw.h b/drivers/misc/mei/hw.h
index b1a8d5ec88b3..8c0297f0e7f3 100644
--- a/drivers/misc/mei/hw.h
+++ b/drivers/misc/mei/hw.h
@@ -346,13 +346,13 @@ struct hbm_add_client_request {
* @hbm_cmd: bus message command header
* @me_addr: address of the client in ME
* @status: if HBMS_SUCCESS then the client can now accept connections.
- * @reserved: reserved
+ * @reserved: reserved for alignment.
*/
struct hbm_add_client_response {
u8 hbm_cmd;
u8 me_addr;
u8 status;
- u8 reserved[1];
+ u8 reserved;
} __packed;

/**
@@ -461,7 +461,7 @@ struct hbm_notification {
u8 hbm_cmd;
u8 me_addr;
u8 host_addr;
- u8 reserved[1];
+ u8 reserved;
} __packed;

/**
--
2.27.0
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