Re: [RFC PATCH v1 1/2] vsock: return errors other than -ENOMEM to socket

Re: [RFC PATCH v1 1/2] vsock: return errors other than -ENOMEM to socket

[Stefano Garzarella]

On Sun, Mar 26, 2023 at 01:13:11AM +0300, Arseniy Krasnov wrote:
>This removes behaviour, where error code returned from any transport
>was always switched to ENOMEM. This works in the same way as:
>commit
>c43170b7e157 ("vsock: return errors other than -ENOMEM to socket"),
>but for receive calls.
>
>Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>---
> net/vmw_vsock/af_vsock.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 19aea7cba26e..9262e0b77d47 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -2007,7 +2007,7 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
>
> 		read = transport->stream_dequeue(vsk, msg, len - copied, flags);

In vmci_transport_stream_dequeue() vmci_qpair_peekv() and
vmci_qpair_dequev() return VMCI_ERROR_* in case of errors.

Maybe we should return -ENOMEM in vmci_transport_stream_dequeue() if
those functions fail to keep the same behavior.

CCing Bryan, Vishnu, and pv-drivers@vmware.com

The other transports seem okay to me.

Thanks,
Stefano

> 		if (read < 0) {
>-			err = -ENOMEM;
>+			err = read;
> 			break;
> 		}
>
>@@ -2058,7 +2058,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> 	msg_len = transport->seqpacket_dequeue(vsk, msg, flags);
>
> 	if (msg_len < 0) {
>-		err = -ENOMEM;
>+		err = msg_len;
> 		goto out;
> 	}
>
>-- 
>2.25.1
>

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Re: [RFC PATCH v1 1/2] vsock: return errors other than -ENOMEM to socket

[Stefano Garzarella]

I pressed send too early...

CCing Bryan, Vishnu, and pv-drivers@vmware.com

On Tue, Mar 28, 2023 at 11:39 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> On Sun, Mar 26, 2023 at 01:13:11AM +0300, Arseniy Krasnov wrote:
> >This removes behaviour, where error code returned from any transport
> >was always switched to ENOMEM. This works in the same way as:
> >commit
> >c43170b7e157 ("vsock: return errors other than -ENOMEM to socket"),
> >but for receive calls.
> >
> >Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> >---
> > net/vmw_vsock/af_vsock.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> >index 19aea7cba26e..9262e0b77d47 100644
> >--- a/net/vmw_vsock/af_vsock.c
> >+++ b/net/vmw_vsock/af_vsock.c
> >@@ -2007,7 +2007,7 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
> >
> >               read = transport->stream_dequeue(vsk, msg, len - copied, flags);
>
> In vmci_transport_stream_dequeue() vmci_qpair_peekv() and
> vmci_qpair_dequev() return VMCI_ERROR_* in case of errors.
>
> Maybe we should return -ENOMEM in vmci_transport_stream_dequeue() if
> those functions fail to keep the same behavior.
>
> CCing Bryan, Vishnu, and pv-drivers@vmware.com
>
> The other transports seem okay to me.
>
> Thanks,
> Stefano
>
> >               if (read < 0) {
> >-                      err = -ENOMEM;
> >+                      err = read;
> >                       break;
> >               }
> >
> >@@ -2058,7 +2058,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> >       msg_len = transport->seqpacket_dequeue(vsk, msg, flags);
> >
> >       if (msg_len < 0) {
> >-              err = -ENOMEM;
> >+              err = msg_len;
> >               goto out;
> >       }
> >
> >--
> >2.25.1
> >

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Re: [RFC PATCH v1 1/2] vsock: return errors other than -ENOMEM to socket

[Stefano Garzarella]

On Tue, Mar 28, 2023 at 01:42:19PM +0300, Arseniy Krasnov wrote:
>
>
>On 28.03.2023 12:42, Stefano Garzarella wrote:
>> I pressed send too early...
>>
>> CCing Bryan, Vishnu, and pv-drivers@vmware.com
>>
>> On Tue, Mar 28, 2023 at 11:39 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>>
>>> On Sun, Mar 26, 2023 at 01:13:11AM +0300, Arseniy Krasnov wrote:
>>>> This removes behaviour, where error code returned from any transport
>>>> was always switched to ENOMEM. This works in the same way as:
>>>> commit
>>>> c43170b7e157 ("vsock: return errors other than -ENOMEM to socket"),
>>>> but for receive calls.
>>>>
>>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>>>> ---
>>>> net/vmw_vsock/af_vsock.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>>>> index 19aea7cba26e..9262e0b77d47 100644
>>>> --- a/net/vmw_vsock/af_vsock.c
>>>> +++ b/net/vmw_vsock/af_vsock.c
>>>> @@ -2007,7 +2007,7 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
>>>>
>>>>               read = transport->stream_dequeue(vsk, msg, len - copied, flags);
>>>
>>> In vmci_transport_stream_dequeue() vmci_qpair_peekv() and
>>> vmci_qpair_dequev() return VMCI_ERROR_* in case of errors.
>>>
>>> Maybe we should return -ENOMEM in vmci_transport_stream_dequeue() if
>>> those functions fail to keep the same behavior.
>
>Yes, seems i missed it, because several months ago we had similar question for send
>logic:
>https://www.spinics.net/lists/kernel/msg4611091.html
>And it was ok to not handle VMCI send path in this way. So i think current implementation
>for tx is a little bit buggy, because VMCI specific error from 'vmci_qpair_enquev()' is
>returned to af_vsock.c. I think error conversion must be added to VMCI transport for tx
>also.

Good point!

These are negative values, so there are no big problems, but I don't
know what the user expects in this case.

@Vishnu Do we want to return an errno to the user or a VMCI_ERROR_*?

In both cases I think we should do the same for both enqueue and
dequeue.

>
>Good thing is that Hyper-V uses general error codes.

Yeah!

Thanks,
Stefano

>
>Thanks, Arseniy
>>>
>>> CCing Bryan, Vishnu, and pv-drivers@vmware.com
>>>
>>> The other transports seem okay to me.
>>>
>>> Thanks,
>>> Stefano
>>>
>>>>               if (read < 0) {
>>>> -                      err = -ENOMEM;
>>>> +                      err = read;
>>>>                       break;
>>>>               }
>>>>
>>>> @@ -2058,7 +2058,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>>>>       msg_len = transport->seqpacket_dequeue(vsk, msg, flags);
>>>>
>>>>       if (msg_len < 0) {
>>>> -              err = -ENOMEM;
>>>> +              err = msg_len;
>>>>               goto out;
>>>>       }
>>>>
>>>> --
>>>> 2.25.1
>>>>
>>
>

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Re: [RFC PATCH v1 1/2] vsock: return errors other than -ENOMEM to socket

[Vishnu Dasa via Virtualization]

> On Mar 28, 2023, at 4:20 AM, Arseniy Krasnov <AVKrasnov@sberdevices.ru> wrote:
> 
> !! External Email
> 
> On 28.03.2023 14:19, Stefano Garzarella wrote:
>> On Tue, Mar 28, 2023 at 01:42:19PM +0300, Arseniy Krasnov wrote:
>>> 
>>> 
>>> On 28.03.2023 12:42, Stefano Garzarella wrote:
>>>> I pressed send too early...
>>>> 
>>>> CCing Bryan, Vishnu, and pv-drivers@vmware.com
>>>> 
>>>> On Tue, Mar 28, 2023 at 11:39 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>>>> 
>>>>> On Sun, Mar 26, 2023 at 01:13:11AM +0300, Arseniy Krasnov wrote:
>>>>>> This removes behaviour, where error code returned from any transport
>>>>>> was always switched to ENOMEM. This works in the same way as:
>>>>>> commit
>>>>>> c43170b7e157 ("vsock: return errors other than -ENOMEM to socket"),
>>>>>> but for receive calls.
>>>>>> 
>>>>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>>>>>> ---
>>>>>> net/vmw_vsock/af_vsock.c | 4 ++--
>>>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>> 
>>>>>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>>>>>> index 19aea7cba26e..9262e0b77d47 100644
>>>>>> --- a/net/vmw_vsock/af_vsock.c
>>>>>> +++ b/net/vmw_vsock/af_vsock.c
>>>>>> @@ -2007,7 +2007,7 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
>>>>>> 
>>>>>>              read = transport->stream_dequeue(vsk, msg, len - copied, flags);
>>>>> 
>>>>> In vmci_transport_stream_dequeue() vmci_qpair_peekv() and
>>>>> vmci_qpair_dequev() return VMCI_ERROR_* in case of errors.
>>>>> 
>>>>> Maybe we should return -ENOMEM in vmci_transport_stream_dequeue() if
>>>>> those functions fail to keep the same behavior.
>>> 
>>> Yes, seems i missed it, because several months ago we had similar question for send
>>> logic:
>>> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.spinics.net%2Flists%2Fkernel%2Fmsg4611091.html&data=05%7C01%7Cvdasa%40vmware.com%7C3b17793425384debe75708db2f7eec8c%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C0%7C638155994413494900%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=MMfFcKuFFvMcJrbToKvWvIB%2FZmzp%2BdGGVWFVWztuSzg%3D&reserved=0
>>> And it was ok to not handle VMCI send path in this way. So i think current implementation
>>> for tx is a little bit buggy, because VMCI specific error from 'vmci_qpair_enquev()' is
>>> returned to af_vsock.c. I think error conversion must be added to VMCI transport for tx
>>> also.
>> 
>> Good point!
>> 
>> These are negative values, so there are no big problems, but I don't
>> know what the user expects in this case.
>> 
>> @Vishnu Do we want to return an errno to the user or a VMCI_ERROR_*?
> 
> Small remark, as i can see, VMCI_ERROR_ is not exported to user in include/uapi,
> so IIUC user won't be able to interpret such values correctly.
> 
> Thanks, Arseniy

Let's just return -ENOMEM from vmci transport in case of error in
vmci_transport_stream_enqueue and vmci_transport_stream_dequeue.

@Arseniy,
Could you please add a separate patch in this set to handle the above?

Thanks,
Vishnu

> 
>> 
>> In both cases I think we should do the same for both enqueue and
>> dequeue.
>> 
>>> 
>>> Good thing is that Hyper-V uses general error codes.
>> 
>> Yeah!
>> 
>> Thanks,
>> Stefano
>> 
>>> 
>>> Thanks, Arseniy
>>>>> 
>>>>> CCing Bryan, Vishnu, and pv-drivers@vmware.com
>>>>> 
>>>>> The other transports seem okay to me.
>>>>> 
>>>>> Thanks,
>>>>> Stefano
>>>>> 
>>>>>>              if (read < 0) {
>>>>>> -                      err = -ENOMEM;
>>>>>> +                      err = read;
>>>>>>                      break;
>>>>>>              }
>>>>>> 
>>>>>> @@ -2058,7 +2058,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>>>>>>      msg_len = transport->seqpacket_dequeue(vsk, msg, flags);
>>>>>> 
>>>>>>      if (msg_len < 0) {
>>>>>> -              err = -ENOMEM;
>>>>>> +              err = msg_len;
>>>>>>              goto out;
>>>>>>      }
>>>>>> 
>>>>>> --
>>>>>> 2.25.1
>>>>>> 
>>>> 
>>> 
>> 
> 
> !! External Email: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender.


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Re: [RFC PATCH v1 2/2] vsock/test: update expected return values

[Stefano Garzarella]

On Sun, Mar 26, 2023 at 01:14:01AM +0300, Arseniy Krasnov wrote:
>This updates expected return values for invalid buffer test. Now such
>values are returned from transport, not from af_vsock.c.

Since only virtio transport supports it for now, it's okay.
In the future we should make sure that we have the same behavior between 
transports.

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

>
>Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>---
> tools/testing/vsock/vsock_test.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
>index 3de10dbb50f5..a91d0ef963be 100644
>--- a/tools/testing/vsock/vsock_test.c
>+++ b/tools/testing/vsock/vsock_test.c
>@@ -723,7 +723,7 @@ static void test_seqpacket_invalid_rec_buffer_server(const struct test_opts *opt
> 		exit(EXIT_FAILURE);
> 	}
>
>-	if (errno != ENOMEM) {
>+	if (errno != EFAULT) {
> 		perror("unexpected errno of 'broken_buf'");
> 		exit(EXIT_FAILURE);
> 	}
>@@ -887,7 +887,7 @@ static void test_inv_buf_client(const struct test_opts *opts, bool stream)
> 		exit(EXIT_FAILURE);
> 	}
>
>-	if (errno != ENOMEM) {
>+	if (errno != EFAULT) {
> 		fprintf(stderr, "unexpected recv(2) errno %d\n", errno);
> 		exit(EXIT_FAILURE);
> 	}
>-- 
>2.25.1
>

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