From: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Sent: Tuesday, December 8, 2020 11:08 PM
>
> Simplify the function by removing various references to the hv_message
> 'msg', introduce local variables 'msgtype' and 'payload_size'.
>
> Suggested-by: Juan Vazquez <juvazq@xxxxxxxxxxxxx>
> Suggested-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> ---
> Changes since v2:
> - Squash patches #2 and #3
> - Revisit commit message
>
> drivers/hv/vmbus_drv.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 502f8cd95f6d4..44bcf9ccdaf5f 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1057,9 +1057,11 @@ void vmbus_on_msg_dpc(unsigned long data)
> struct hv_message *msg = (struct hv_message *)page_addr +
> VMBUS_MESSAGE_SINT;
> struct vmbus_channel_message_header *hdr;
> + enum vmbus_channel_message_type msgtype;
> const struct vmbus_channel_message_table_entry *entry;
> struct onmessage_work_context *ctx;
> u32 message_type = msg->header.message_type;
> + __u8 payload_size;
>
> /*
> * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
> @@ -1073,40 +1075,38 @@ void vmbus_on_msg_dpc(unsigned long data)
> return;
>
> hdr = (struct vmbus_channel_message_header *)msg->u.payload;
> + msgtype = hdr->msgtype;
>
> trace_vmbus_on_msg_dpc(hdr);
>
> - if (hdr->msgtype >= CHANNELMSG_COUNT) {
> - WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
> + if (msgtype >= CHANNELMSG_COUNT) {
> + WARN_ONCE(1, "unknown msgtype=%d\n", msgtype);
> goto msg_handled;
> }
>
> - if (msg->header.payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
> - WARN_ONCE(1, "payload size is too large (%d)\n",
> - msg->header.payload_size);
> + payload_size = msg->header.payload_size;
> + if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
> + WARN_ONCE(1, "payload size is too large (%d)\n", payload_size);
> goto msg_handled;
> }
>
> - entry = &channel_message_table[hdr->msgtype];
> + entry = &channel_message_table[msgtype];
>
> if (!entry->message_handler)
> goto msg_handled;
>
> - if (msg->header.payload_size < entry->min_payload_len) {
> - WARN_ONCE(1, "message too short: msgtype=%d len=%d\n",
> - hdr->msgtype, msg->header.payload_size);
> + if (payload_size < entry->min_payload_len) {
> + WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype,
> payload_size);
> goto msg_handled;
> }
>
> if (entry->handler_type == VMHT_BLOCKING) {
> - ctx = kmalloc(sizeof(*ctx) + msg->header.payload_size,
> - GFP_ATOMIC);
> + ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC);
> if (ctx == NULL)
> return;
>
> INIT_WORK(&ctx->work, vmbus_onmessage_work);
> - memcpy(&ctx->msg, msg, sizeof(msg->header) +
> - msg->header.payload_size);
> + memcpy(&ctx->msg, msg, sizeof(msg->header) + payload_size);
>
> /*
> * The host can generate a rescind message while we
> @@ -1115,7 +1115,7 @@ void vmbus_on_msg_dpc(unsigned long data)
> * by offer_in_progress and by channel_mutex. See also the
> * inline comments in vmbus_onoffer_rescind().
> */
> - switch (hdr->msgtype) {
> + switch (msgtype) {
> case CHANNELMSG_RESCIND_CHANNELOFFER:
> /*
> * If we are handling the rescind message;
> --
> 2.25.1
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
