diff mbox

[PATCH-v4-RESEND,1/4] vsock: track pkt owner vsock

Message ID 1488340587-32416-2-git-send-email-bergwolf@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Peng Tao March 1, 2017, 3:56 a.m. UTC 
So that we can cancel a queued pkt later if necessary.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
---
 include/linux/virtio_vsock.h            | 2 ++
 net/vmw_vsock/virtio_transport_common.c | 7 +++++++
 2 files changed, 9 insertions(+)

Comments

David Miller March 2, 2017, 9:13 p.m. UTC | #1 
From: Peng Tao <bergwolf@gmail.com>
Date: Wed,  1 Mar 2017 11:56:24 +0800

> So that we can cancel a queued pkt later if necessary.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Peng Tao <bergwolf@gmail.com>
> ---
>  include/linux/virtio_vsock.h            | 2 ++
>  net/vmw_vsock/virtio_transport_common.c | 7 +++++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> index 9638bfe..193ad3a 100644
> --- a/include/linux/virtio_vsock.h
> +++ b/include/linux/virtio_vsock.h
> @@ -48,6 +48,7 @@ struct virtio_vsock_pkt {
>  	struct virtio_vsock_hdr	hdr;
>  	struct work_struct work;
>  	struct list_head list;
> +	void *cancel_token; /* only used for cancellation */

The type here is fixed, you only store vhost_sock object pointers
here, so don't use "void *" please.
Peng Tao March 3, 2017, 1:25 a.m. UTC | #2 
On Fri, Mar 3, 2017 at 5:13 AM, David Miller <davem@davemloft.net> wrote:
> From: Peng Tao <bergwolf@gmail.com>
> Date: Wed,  1 Mar 2017 11:56:24 +0800
>
>> So that we can cancel a queued pkt later if necessary.
>>
>> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>> Signed-off-by: Peng Tao <bergwolf@gmail.com>
>> ---
>>  include/linux/virtio_vsock.h            | 2 ++
>>  net/vmw_vsock/virtio_transport_common.c | 7 +++++++
>>  2 files changed, 9 insertions(+)
>>
>> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>> index 9638bfe..193ad3a 100644
>> --- a/include/linux/virtio_vsock.h
>> +++ b/include/linux/virtio_vsock.h
>> @@ -48,6 +48,7 @@ struct virtio_vsock_pkt {
>>       struct virtio_vsock_hdr hdr;
>>       struct work_struct work;
>>       struct list_head list;
>> +     void *cancel_token; /* only used for cancellation */
>
> The type here is fixed, you only store vhost_sock object pointers
> here, so don't use "void *" please.
It used to be "struct vhost_sock *" but no refcount is held. Stefan
suggested to use "void *cancel_token" to make the code harder to
misuse.

Quoting Stefan:
"This field is just an opaque token used for cancellation rather than
a struct vsock_sock pointer that we are allowed to dereference.  You
could change this field to void *cancel_token to make the code harder
to misuse."

Ref:
https://www.mail-archive.com/netdev@vger.kernel.org/msg142550.html

Cheers,
Tao
Stefan Hajnoczi March 10, 2017, 1:48 a.m. UTC | #3 
On Fri, Mar 03, 2017 at 09:25:54AM +0800, Peng Tao wrote:
> On Fri, Mar 3, 2017 at 5:13 AM, David Miller <davem@davemloft.net> wrote:
> > From: Peng Tao <bergwolf@gmail.com>
> > Date: Wed,  1 Mar 2017 11:56:24 +0800
> >
> >> So that we can cancel a queued pkt later if necessary.
> >>
> >> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> >> Signed-off-by: Peng Tao <bergwolf@gmail.com>
> >> ---
> >>  include/linux/virtio_vsock.h            | 2 ++
> >>  net/vmw_vsock/virtio_transport_common.c | 7 +++++++
> >>  2 files changed, 9 insertions(+)
> >>
> >> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> >> index 9638bfe..193ad3a 100644
> >> --- a/include/linux/virtio_vsock.h
> >> +++ b/include/linux/virtio_vsock.h
> >> @@ -48,6 +48,7 @@ struct virtio_vsock_pkt {
> >>       struct virtio_vsock_hdr hdr;
> >>       struct work_struct work;
> >>       struct list_head list;
> >> +     void *cancel_token; /* only used for cancellation */
> >
> > The type here is fixed, you only store vhost_sock object pointers
> > here, so don't use "void *" please.
> It used to be "struct vhost_sock *" but no refcount is held. Stefan
> suggested to use "void *cancel_token" to make the code harder to
> misuse.
> 
> Quoting Stefan:
> "This field is just an opaque token used for cancellation rather than
> a struct vsock_sock pointer that we are allowed to dereference.  You
> could change this field to void *cancel_token to make the code harder
> to misuse."
> 
> Ref:
> https://www.mail-archive.com/netdev@vger.kernel.org/msg142550.html

Yes, the key point is that it shouldn't be used as a struct vsock_sock
since we don't hold a reference.  It's purely a token so the queued
packet can be found later for cancellation.

Stefan
diff mbox

Patch

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 9638bfe..193ad3a 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -48,6 +48,7 @@  struct virtio_vsock_pkt {
 	struct virtio_vsock_hdr	hdr;
 	struct work_struct work;
 	struct list_head list;
+	void *cancel_token; /* only used for cancellation */
 	void *buf;
 	u32 len;
 	u32 off;
@@ -56,6 +57,7 @@  struct virtio_vsock_pkt {
 
 struct virtio_vsock_pkt_info {
 	u32 remote_cid, remote_port;
+	struct vsock_sock *vsk;
 	struct msghdr *msg;
 	u32 pkt_len;
 	u16 type;
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 849c4ad..ab505f1 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -57,6 +57,7 @@  virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
 	pkt->len		= len;
 	pkt->hdr.len		= cpu_to_le32(len);
 	pkt->reply		= info->reply;
+	pkt->cancel_token	= info->vsk;
 
 	if (info->msg && len > 0) {
 		pkt->buf = kmalloc(len, GFP_KERNEL);
@@ -179,6 +180,7 @@  static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
 	struct virtio_vsock_pkt_info info = {
 		.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
 		.type = type,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -518,6 +520,7 @@  int virtio_transport_connect(struct vsock_sock *vsk)
 	struct virtio_vsock_pkt_info info = {
 		.op = VIRTIO_VSOCK_OP_REQUEST,
 		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -533,6 +536,7 @@  int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
 			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
 			 (mode & SEND_SHUTDOWN ?
 			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -559,6 +563,7 @@  virtio_transport_stream_enqueue(struct vsock_sock *vsk,
 		.type = VIRTIO_VSOCK_TYPE_STREAM,
 		.msg = msg,
 		.pkt_len = len,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -580,6 +585,7 @@  static int virtio_transport_reset(struct vsock_sock *vsk,
 		.op = VIRTIO_VSOCK_OP_RST,
 		.type = VIRTIO_VSOCK_TYPE_STREAM,
 		.reply = !!pkt,
+		.vsk = vsk,
 	};
 
 	/* Send RST only if the original pkt is not a RST pkt */
@@ -825,6 +831,7 @@  virtio_transport_send_response(struct vsock_sock *vsk,
 		.remote_cid = le64_to_cpu(pkt->hdr.src_cid),
 		.remote_port = le32_to_cpu(pkt->hdr.src_port),
 		.reply = true,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);