linux-kernel - Re: [PATCH v2 7/8] vdpa_sim: replace the spinlock with a mutex to protect the state

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Date:   Thu, 16 Mar 2023 09:42:48 +0100
From:   Stefano Garzarella <sgarzare@...hat.com>
To:     Jason Wang <jasowang@...hat.com>
Cc:     virtualization@...ts.linux-foundation.org,
        Andrey Zhadchenko <andrey.zhadchenko@...tuozzo.com>,
        eperezma@...hat.com, netdev@...r.kernel.org, stefanha@...hat.com,
        linux-kernel@...r.kernel.org,
        "Michael S. Tsirkin" <mst@...hat.com>, kvm@...r.kernel.org
Subject: Re: [PATCH v2 7/8] vdpa_sim: replace the spinlock with a mutex to
 protect the state

On Tue, Mar 14, 2023 at 01:31:25PM +0800, Jason Wang wrote:
>On Tue, Mar 14, 2023 at 1:29 PM Jason Wang <jasowang@...hat.com> wrote:
>>
>> On Thu, Mar 2, 2023 at 7:35 PM Stefano Garzarella <sgarzare@...hat.com> wrote:
>> >
>> > The spinlock we use to protect the state of the simulator is sometimes
>> > held for a long time (for example, when devices handle requests).
>> >
>> > This also prevents us from calling functions that might sleep (such as
>> > kthread_flush_work() in the next patch), and thus having to release
>> > and retake the lock.
>> >
>> > For these reasons, let's replace the spinlock with a mutex that gives
>> > us more flexibility.
>> >
>> > Suggested-by: Jason Wang <jasowang@...hat.com>
>> > Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
>>
>> Acked-by: Jason Wang <jasowang@...hat.com>
>>
>> Thanks
>
>Btw, though it looks fine but we'd better double confirm virtio_vdpa works well.

I tested it, but I will do it more carefully to make sure everything
is okay.

>
>(I think so since there's transport that might sleep).

I see.

Thanks,
Stefano