Re: [RFC PATCH v9 19/19] af_vsock: serialize writes to shared socket

From: Stefano Garzarella <sgarzare@redhat.com>
To: Arseny Krasnov <arseny.krasnov@kaspersky.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jorgen Hansen <jhansen@vmware.com>,
	Norbert Slusarek <nslusarek@gmx.net>,
	Andra Paraschiv <andraprs@amazon.com>,
	Colin Ian King <colin.king@canonical.com>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	stsp2@yandex.ru, oxffffaa@gmail.com
Subject: Re: [RFC PATCH v9 19/19] af_vsock: serialize writes to shared socket
Date: Thu, 13 May 2021 16:46:53 +0200	[thread overview]
Message-ID: <20210513144653.ogzfvypqpjsz2iga@steredhat> (raw)
In-Reply-To: <20210513140150.ugw6foy742fxan4w@steredhat>

On Thu, May 13, 2021 at 04:01:50PM +0200, Stefano Garzarella wrote:
>On Sat, May 08, 2021 at 07:37:35PM +0300, Arseny Krasnov wrote:
>>This add logic, that serializes write access to single socket
>>by multiple threads. It is implemented be adding field with TID
>>of current writer. When writer tries to send something, it checks
>>that field is -1(free), else it sleep in the same way as waiting
>>for free space at peers' side.
>>
>>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>>---
>>include/net/af_vsock.h   |  1 +
>>net/vmw_vsock/af_vsock.c | 10 +++++++++-
>>2 files changed, 10 insertions(+), 1 deletion(-)
>
>I think you forgot to move this patch at the beginning of the series.
>It's important because in this way we can backport to stable branches 
>easily.
>
>About the implementation, can't we just add a mutex that we hold until 
>we have sent all the payload?

Re-thinking, I guess we can't because we have the timeout to deal 
with...

>
>I need to check other implementations like TCP.
>

Thanks,
Stefano