Re: [PATCH 2/8] net: qualcomm: rmnet: kill RMNET_MAP_GET_*() accessor macros

From: Bjorn Andersson
Date: Mon May 20 2019 - 11:43:10 EST

On Mon 20 May 06:53 PDT 2019, Alex Elder wrote:

> The following macros, defined in "rmnet_map.h", assume a socket
> buffer is provided as an argument without any real indication this
> is the case.
> RMNET_MAP_GET_MUX_ID()
> RMNET_MAP_GET_CD_BIT()
> RMNET_MAP_GET_PAD()
> RMNET_MAP_GET_CMD_START()
> RMNET_MAP_GET_LENGTH()
> What they hide is pretty trivial accessing of fields in a structure,
> and it's much clearer to see this if we do these accesses directly.
>
> So rather than using these accessor macros, assign a local
> variable of the map header pointer type to the socket buffer data
> pointer, and derereference that pointer variable.
>
> Use the network byte order macros (e.g., ntohs()), not the Linux
> byte order functions (e.g. be_to_cpu16()) to convert the big-endian
> packet length field, to match the convention used elswhere in the
> driver.
>
> There's no need to byte swap 0; it's all zeros irrespective of
> endianness.
>

Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>

> Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
> ---
> drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 9 +++++----
> drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h | 12 ------------
> .../net/ethernet/qualcomm/rmnet/rmnet_map_command.c | 11 ++++++++---
> drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 4 ++--
> 4 files changed, 15 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
> index 11167abe5934..4c1b62b72504 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
> @@ -65,20 +65,21 @@ static void
> __rmnet_map_ingress_handler(struct sk_buff *skb,
> struct rmnet_port *port)
> {
> + struct rmnet_map_header *map_header = (void *)skb->data;
> struct rmnet_endpoint *ep;
> u16 len, pad;
> u8 mux_id;
>
> - if (RMNET_MAP_GET_CD_BIT(skb)) {
> + if (map_header->cd_bit) {
> if (port->data_format & RMNET_FLAGS_INGRESS_MAP_COMMANDS)
> return rmnet_map_command(skb, port);
>
> goto free_skb;
> }
>
> - mux_id = RMNET_MAP_GET_MUX_ID(skb);
> - pad = RMNET_MAP_GET_PAD(skb);
> - len = RMNET_MAP_GET_LENGTH(skb) - pad;
> + mux_id = map_header->mux_id;
> + pad = map_header->pad_len;
> + len = ntohs(map_header->pkt_len) - pad;
>
> if (mux_id >= RMNET_MAX_LOGICAL_EP)
> goto free_skb;
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
> index b1ae9499c0b2..a30a7b405a11 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
> @@ -63,18 +63,6 @@ struct rmnet_map_ul_csum_header {
> u16 csum_enabled:1;
> } __aligned(1);
>
> -#define RMNET_MAP_GET_MUX_ID(Y) (((struct rmnet_map_header *) \
> - (Y)->data)->mux_id)
> -#define RMNET_MAP_GET_CD_BIT(Y) (((struct rmnet_map_header *) \
> - (Y)->data)->cd_bit)
> -#define RMNET_MAP_GET_PAD(Y) (((struct rmnet_map_header *) \
> - (Y)->data)->pad_len)
> -#define RMNET_MAP_GET_CMD_START(Y) ((struct rmnet_map_control_command *) \
> - ((Y)->data + \
> - sizeof(struct rmnet_map_header)))
> -#define RMNET_MAP_GET_LENGTH(Y) (ntohs(((struct rmnet_map_header *) \
> - (Y)->data)->pkt_len))
> -
> #define RMNET_MAP_COMMAND_REQUEST 0
> #define RMNET_MAP_COMMAND_ACK 1
> #define RMNET_MAP_COMMAND_UNSUPPORTED 2
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
> index f6cf59aee212..f675f47c3495 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
> @@ -20,12 +20,13 @@ static u8 rmnet_map_do_flow_control(struct sk_buff *skb,
> struct rmnet_port *port,
> int enable)
> {
> + struct rmnet_map_header *map_header = (void *)skb->data;
> struct rmnet_endpoint *ep;
> struct net_device *vnd;
> u8 mux_id;
> int r;
>
> - mux_id = RMNET_MAP_GET_MUX_ID(skb);
> + mux_id = map_header->mux_id;
>
> if (mux_id >= RMNET_MAX_LOGICAL_EP) {
> kfree_skb(skb);
> @@ -57,6 +58,7 @@ static void rmnet_map_send_ack(struct sk_buff *skb,
> unsigned char type,
> struct rmnet_port *port)
> {
> + struct rmnet_map_header *map_header = (void *)skb->data;
> struct rmnet_map_control_command *cmd;
> struct net_device *dev = skb->dev;
>
> @@ -66,7 +68,8 @@ static void rmnet_map_send_ack(struct sk_buff *skb,
>
> skb->protocol = htons(ETH_P_MAP);
>
> - cmd = RMNET_MAP_GET_CMD_START(skb);
> + /* Command data immediately follows the header */
> + cmd = (struct rmnet_map_control_command *)(map_header + 1);
> cmd->cmd_type = type & 0x03;
>
> netif_tx_lock(dev);
> @@ -79,11 +82,13 @@ static void rmnet_map_send_ack(struct sk_buff *skb,
> */
> void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port)
> {
> + struct rmnet_map_header *map_header = (void *)skb->data;
> struct rmnet_map_control_command *cmd;
> unsigned char command_name;
> unsigned char rc = 0;
>
> - cmd = RMNET_MAP_GET_CMD_START(skb);
> + /* Command data immediately follows the header */
> + cmd = (struct rmnet_map_control_command *)(map_header + 1);
> command_name = cmd->command_name;
>
> switch (command_name) {
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> index 57a9c314a665..498f20ba1826 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> @@ -323,7 +323,7 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
> return NULL;
>
> maph = (struct rmnet_map_header *)skb->data;
> - packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header);
> + packet_len = ntohs(maph->pkt_len) + sizeof(*maph);
>
> if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4)
> packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
> @@ -332,7 +332,7 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
> return NULL;
>
> /* Some hardware can send us empty frames. Catch them */
> - if (ntohs(maph->pkt_len) == 0)
> + if (!maph->pkt_len)
> return NULL;
>
> skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
> --
> 2.20.1
>