[PATCH v5] Add payload to be 32-bit aligned to fix dropped packets
Jakub Kicinski
kuba at kernel.org
Tue Nov 16 05:02:16 AEDT 2021
On Mon, 15 Nov 2021 20:18:46 +0530 Kumar Thangavel wrote:
> @@ -213,12 +215,16 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,
> {
> struct ncsi_cmd_oem_pkt *cmd;
> unsigned int len;
> + /* NC-SI spec DSP_0222_1.2.0, section 8.2.2.2
> + * requires payload to be padded with 0 to
> + * 32-bit boundary before the checksum field.
> + * Ensure the padding bytes are accounted for in
> + * skb allocation
> + */
>
> + unsigned short payload = ALIGN(nca->payload, 4);
> len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;
This looks like mixing code and declarations.
If a piece of code is important enough to warrant a comment it should
not be placed as variable init.
> @@ -272,6 +278,7 @@ static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
> struct net_device *dev = nd->dev;
> int hlen = LL_RESERVED_SPACE(dev);
> int tlen = dev->needed_tailroom;
> + int payload;
> int len = hlen + tlen;
> struct sk_buff *skb;
> struct ncsi_request *nr;
> @@ -281,14 +288,14 @@ static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
> return NULL;
>
> /* NCSI command packet has 16-bytes header, payload, 4 bytes checksum.
> + * Payload needs padding so that the checksum field following payload is
> + * aligned to 32-bit boundary.
> * The packet needs padding if its payload is less than 26 bytes to
> * meet 64 bytes minimal ethernet frame length.
> */
> len += sizeof(struct ncsi_cmd_pkt_hdr) + 4;
> - if (nca->payload < 26)
> - len += 26;
> - else
> - len += nca->payload;
> + payload = ALIGN(nca->payload, 4);
> + len += max(payload, padding_bytes);
payload is int here, and padding_bytes is unsigned short, you either
have to use max_t() or change the types to agree.
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