From c56967d674e361ebe716e66992e3c5332b25ac1f Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 22 Jul 2020 13:15:34 -0500 Subject: mei: hdcp: Replace one-element array with flexible-array member MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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]. Also, make use of the array_size() helper instead of the open-coded version in memcpy(). These sorts of multiplication factors need to be wrapped in array_size(). And 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 pointer 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 Link: https://lore.kernel.org/r/20200722181534.GA31357@embeddedor Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/hdcp/mei_hdcp.c | 2 +- drivers/misc/mei/hdcp/mei_hdcp.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/misc') diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c index e6c3dc595617..d1d3e025ca0e 100644 --- a/drivers/misc/mei/hdcp/mei_hdcp.c +++ b/drivers/misc/mei/hdcp/mei_hdcp.c @@ -572,7 +572,7 @@ static int mei_hdcp_verify_mprime(struct device *dev, HDCP_2_2_MPRIME_LEN); drm_hdcp_cpu_to_be24(verify_mprime_in.seq_num_m, data->seq_num_m); memcpy(verify_mprime_in.streams, data->streams, - (data->k * sizeof(struct hdcp2_streamid_type))); + array_size(data->k, sizeof(*data->streams))); verify_mprime_in.k = cpu_to_be16(data->k); diff --git a/drivers/misc/mei/hdcp/mei_hdcp.h b/drivers/misc/mei/hdcp/mei_hdcp.h index 18ffc773fa18..834757f5e072 100644 --- a/drivers/misc/mei/hdcp/mei_hdcp.h +++ b/drivers/misc/mei/hdcp/mei_hdcp.h @@ -358,7 +358,7 @@ struct wired_cmd_repeater_auth_stream_req_in { u8 seq_num_m[HDCP_2_2_SEQ_NUM_LEN]; u8 m_prime[HDCP_2_2_MPRIME_LEN]; __be16 k; - struct hdcp2_streamid_type streams[1]; + struct hdcp2_streamid_type streams[]; } __packed; struct wired_cmd_repeater_auth_stream_req_out { -- cgit v1.2.3