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SubjectRe: [PATCH 3/5] Drivers: hv: kvp: Fix the recent regression caused by incorrect clean-up
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On 10/17/18 7:07 AM, Greg KH wrote:
> On Wed, Oct 17, 2018 at 03:14:04AM +0000, kys@linuxonhyperv.com wrote:
>> From: Dexuan Cui <decui@microsoft.com>
>>
>> In kvp_send_key(), we do need call process_ib_ipinfo() if
>> message->kvp_hdr.operation is KVP_OP_GET_IP_INFO, because it turns out
>> the userland hv_kvp_daemon needs the info of operation, adapter_id and
>> addr_family. With the incorrect fc62c3b1977d, the host can't get the
>> VM's IP via KVP.
>>
>> And, fc62c3b1977d added a "break;", but actually forgot to initialize
>> the key_size/value in the case of KVP_OP_SET, so the default key_size of
>> 0 is passed to the kvp daemon, and the pool files
>> /var/lib/hyperv/.kvp_pool_* can't be updated.
>>
>> This patch effectively rolls back the previous fc62c3b1977d, and
>> correctly fixes the "this statement may fall through" warnings.
>>
>> This patch is tested on WS 2012 R2 and 2016.
>>
>> Fixes: fc62c3b1977d ("Drivers: hv: kvp: Fix two "this statement may fall through" warnings")
>> Signed-off-by: Dexuan Cui <decui@microsoft.com>
>> Cc: K. Y. Srinivasan <kys@microsoft.com>
>> Cc: Haiyang Zhang <haiyangz@microsoft.com>
>> Cc: Stephen Hemminger <sthemmin@microsoft.com>
>> Cc: <Stable@vger.kernel.org>
>> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
>> ---
>> drivers/hv/hv_kvp.c | 26 ++++++++++++++++++++++----
>> 1 file changed, 22 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
>> index a7513a8a8e37..9fbb15c62c6c 100644
>> --- a/drivers/hv/hv_kvp.c
>> +++ b/drivers/hv/hv_kvp.c
>> @@ -353,6 +353,9 @@ static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
>>
>> out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
>>
>> + __attribute__ ((fallthrough));
>
> The comment should be sufficient for this, right? I haven't seen many
> uses of this attribute before, how common is it?
>

It's not common at all.

Dexuan, please use a comment instead: /* fall through */

Thanks
--
Gustavo

>
>> +
>> + case KVP_OP_GET_IP_INFO:
>> utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
>> MAX_ADAPTER_ID_SIZE,
>> UTF16_LITTLE_ENDIAN,
>> @@ -405,7 +408,11 @@ kvp_send_key(struct work_struct *dummy)
>> process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
>> break;
>> case KVP_OP_GET_IP_INFO:
>> - /* We only need to pass on message->kvp_hdr.operation. */
>> + /*
>> + * We only need to pass on the info of operation, adapter_id
>> + * and addr_family to the userland kvp daemon.
>> + */
>> + process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
>> break;
>> case KVP_OP_SET:
>> switch (in_msg->body.kvp_set.data.value_type) {
>> @@ -446,9 +453,9 @@ kvp_send_key(struct work_struct *dummy)
>>
>> }
>>
>> - break;
>> -
>> - case KVP_OP_GET:
>> + /*
>> + * The key is always a string - utf16 encoding.
>> + */
>> message->body.kvp_set.data.key_size =
>> utf16s_to_utf8s(
>> (wchar_t *)in_msg->body.kvp_set.data.key,
>> @@ -456,6 +463,17 @@ kvp_send_key(struct work_struct *dummy)
>> UTF16_LITTLE_ENDIAN,
>> message->body.kvp_set.data.key,
>> HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
>> +
>> + break;
>> +
>> + case KVP_OP_GET:
>> + message->body.kvp_get.data.key_size =
>> + utf16s_to_utf8s(
>> + (wchar_t *)in_msg->body.kvp_get.data.key,
>> + in_msg->body.kvp_get.data.key_size,
>> + UTF16_LITTLE_ENDIAN,
>> + message->body.kvp_get.data.key,
>> + HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
>
> Worst indentation ever :(
>
> Yeah, I know it follows the others above it, but you should reconsider
> it in the future...
>
> thanks,
>
> greg k-h
>

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