On Tue, Jul 08, 2025 at 02:36:11PM +0800, Xuewei Niu wrote:
> From: Dexuan Cui <de...@microsoft.com>
> 
> When hv_sock was originally added, __vsock_stream_recvmsg() and
> vsock_stream_has_data() actually only needed to know whether there
> is any readable data or not, so hvs_stream_has_data() was written to
> return 1 or 0 for simplicity.
> 
> However, now hvs_stream_has_data() should return the readable bytes
> because vsock_data_ready() -> vsock_stream_has_data() needs to know the
> actual bytes rather than a boolean value of 1 or 0.
> 
> The SIOCINQ ioctl support also needs hvs_stream_has_data() to return
> the readable bytes.
> 
> Let hvs_stream_has_data() return the readable bytes of the payload in
> the next host-to-guest VMBus hv_sock packet.
> 
> Note: there may be multiple incoming hv_sock packets pending in the
> VMBus channel's ringbuffer, but so far there is not a VMBus API that
> allows us to know all the readable bytes in total without reading and
> caching the payload of the multiple packets, so let's just return the
> readable bytes of the next single packet. In the future, we'll either
> add a VMBus API that allows us to know the total readable bytes without
> touching the data in the ringbuffer, or the hv_sock driver needs to
> understand the VMBus packet format and parse the packets directly.
> 
> Signed-off-by: Dexuan Cui <de...@microsoft.com>
> Signed-off-by: Xuewei Niu <niuxuewei....@antgroup.com>

Acked-by: Wei Liu <wei....@kernel.org>

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