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From: Long Li <longli@microsoft.com>
To: Saurabh Sengar <ssengar@linux.microsoft.com>, KY Srinivasan
	<kys@microsoft.com>, Haiyang Zhang <haiyangz@microsoft.com>,
	"wei.liu@kernel.org" <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
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	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC: Saurabh Singh Sengar <ssengar@microsoft.com>
Subject: RE: [PATCH 1/6] Drivers: hv: vmbus: Add utility function for querying
 ring size
Thread-Topic: [PATCH 1/6] Drivers: hv: vmbus: Add utility function for
 querying ring size
Thread-Index: AQHaYcvPQWb8WXDgsUGM5pUS3fQcJbE0u2xg
Date: Tue, 12 Mar 2024 20:57:35 +0000
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> Subject: [PATCH 1/6] Drivers: hv: vmbus: Add utility function for queryin=
g ring size
>=20
> Add a function to query for the preferred ring buffer size of VMBus devic=
e.

Patch looks good to me. It will be helpful if you can document the ring siz=
es for each device and put it in the comment. (e.g  use a new ring size, or=
 keep using an existing ring size)

>=20
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
>  drivers/hv/channel_mgmt.c | 7 +++++--
>  drivers/hv/hyperv_vmbus.h | 5 +++++
>  include/linux/hyperv.h    | 1 +
>  3 files changed, 11 insertions(+), 2 deletions(-)
>=20
> diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index
> 2f4d09ce027a..7ea444d72f9f 100644
> --- a/drivers/hv/channel_mgmt.c
> +++ b/drivers/hv/channel_mgmt.c
> @@ -120,7 +120,8 @@ const struct vmbus_device vmbus_devs[] =3D {
>  	},
>=20
>  	/* File copy */
> -	{ .dev_type =3D HV_FCOPY,
> +	{ .pref_ring_size =3D 0x4000,
> +	  .dev_type =3D HV_FCOPY,
>  	  HV_FCOPY_GUID,
>  	  .perf_device =3D false,
>  	  .allowed_in_isolated =3D false,
> @@ -141,11 +142,13 @@ const struct vmbus_device vmbus_devs[] =3D {
>  	},
>=20
>  	/* Unknown GUID */
> -	{ .dev_type =3D HV_UNKNOWN,
> +	{ .pref_ring_size =3D 0x11000,
> +	  .dev_type =3D HV_UNKNOWN,
>  	  .perf_device =3D false,
>  	  .allowed_in_isolated =3D false,
>  	},
>  };
> +EXPORT_SYMBOL_GPL(vmbus_devs);
>=20
>  static const struct {
>  	guid_t guid;
> diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index
> f6b1e710f805..76ac5185a01a 100644
> --- a/drivers/hv/hyperv_vmbus.h
> +++ b/drivers/hv/hyperv_vmbus.h
> @@ -417,6 +417,11 @@ static inline bool hv_is_perf_channel(struct
> vmbus_channel *channel)
>  	return vmbus_devs[channel->device_id].perf_device;
>  }
>=20
> +static inline size_t hv_dev_ring_size(struct vmbus_channel *channel) {
> +	return vmbus_devs[channel->device_id].pref_ring_size;
> +}
> +
>  static inline bool hv_is_allocated_cpu(unsigned int cpu)  {
>  	struct vmbus_channel *channel, *sc;
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index
> 2b00faf98017..5951c7bb5712 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -800,6 +800,7 @@ struct vmbus_requestor {  #define VMBUS_RQST_RESET
> (U64_MAX - 3)
>=20
>  struct vmbus_device {
> +	size_t pref_ring_size;
>  	u16  dev_type;
>  	guid_t guid;
>  	bool perf_device;
> --
> 2.34.1
>=20