Re: [PATCH 03/17] Drivers: hv: kvp: Cleanup error handling in KVP
From: Ben Hutchings <hidden>
Date: 2012-07-25 01:11:03
Also in:
lkml, virtualization
On Tue, 2012-07-24 at 09:01 -0700, K. Y. Srinivasan wrote:
quoted hunk ↗ jump to hunk
In preparation to implementing IP injection, cleanup the way we propagate and handle errors both in the driver as well as in the user level daemon. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> --- drivers/hv/hv_kvp.c | 112 +++++++++++++++++++++++++++++++++++++--------- include/linux/hyperv.h | 17 +++++--- tools/hv/hv_kvp_daemon.c | 70 +++++++++++++++------------- 3 files changed, 138 insertions(+), 61 deletions(-)diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c index 0012eed..9b7fc4a 100644 --- a/drivers/hv/hv_kvp.c +++ b/drivers/hv/hv_kvp.c
[...]
quoted hunk ↗ jump to hunk
@@ -109,27 +154,52 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp) { struct hv_kvp_msg *message; struct hv_kvp_msg_enumerate *data; + int error = 0; message = (struct hv_kvp_msg *)msg->data; - switch (message->kvp_hdr.operation) { + + /* + * If we are negotiating the version information + * with the daemon; handle that first. + */ + + if (in_hand_shake) { + if (kvp_handle_handshake(message)) + in_hand_shake = false; + return; + } + + /* + * Based on the version of the daemon, we propagate errors from the + * daemon differently. + */ + + data = &message->body.kvp_enum_data; + + switch (dm_reg_value) { case KVP_OP_REGISTER: - pr_info("KVP: user-mode registering done.\n"); - kvp_register(); - kvp_transaction.active = false; - hv_kvp_onchannelcallback(kvp_transaction.kvp_context); + /* + * Null string is used to pass back error condition. + */ + if (!strlen(data->data.key))
Do we know that the key is null-terminated here? Shouldn't we just check whether data->data.key[0] == 0?
+ error = HV_S_CONT; break; - default: - data = &message->body.kvp_enum_data; + case KVP_OP_REGISTER1: /* - * Complete the transaction by forwarding the key value - * to the host. But first, cancel the timeout. + * We use the message header information from + * the user level daemon to transmit errors. */ - if (cancel_delayed_work_sync(&kvp_work)) - kvp_respond_to_host(data->data.key, - data->data.value, - !strlen(data->data.key)); + error = *((int *)(&message->kvp_hdr.operation));
[...]
What's with the casting (repeated in many other places)? Wouldn't it be
better to redefine struct hv_kvp_msg to start with something like:
union {
struct hv_kvp_hdr request;
int error;
} kvp_hdr;
Ben.
--
Ben Hutchings
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