Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [Patch v5 2/3] Drivers: hv: add Azure Blob driver
To:     longli@linuxonhyperv.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org
Cc:     Long Li <longli@microsoft.com>, Jonathan Corbet <corbet@lwn.net>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Maximilian Luz <luzmaximilian@gmail.com>,
        Mike Rapoport <rppt@kernel.org>,
        Ben Widawsky <ben.widawsky@intel.com>,
        Jiri Slaby <jirislaby@kernel.org>,
        Andra Paraschiv <andraprs@amazon.com>,
        Siddharth Gupta <sidgup@codeaurora.org>,
        Hannes Reinecke <hare@suse.de>, linux-doc@vger.kernel.org
References: <1628146812-29798-1-git-send-email-longli@linuxonhyperv.com>
 <1628146812-29798-3-git-send-email-longli@linuxonhyperv.com>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <b6404b38-9ea2-b438-dc1b-1196f8e4a158@acm.org>
Date:   Thu, 5 Aug 2021 10:06:03 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.12.0
MIME-Version: 1.0
In-Reply-To: <1628146812-29798-3-git-send-email-longli@linuxonhyperv.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 8/5/21 12:00 AM, longli@linuxonhyperv.com wrote:
> diff --git a/include/uapi/misc/hv_azure_blob.h b/include/uapi/misc/hv_azure_blob.h
> new file mode 100644
> index 0000000..87a3f77
> --- /dev/null
> +++ b/include/uapi/misc/hv_azure_blob.h
> @@ -0,0 +1,35 @@
> +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
> +/* Copyright (c) 2021 Microsoft Corporation. */
> +
> +#ifndef _AZ_BLOB_H
> +#define _AZ_BLOB_H
> +
> +#include <linux/ioctl.h>
> +#include <linux/uuid.h>
> +#include <linux/types.h>
> +
> +/* user-mode sync request sent through ioctl */
> +struct az_blob_request_sync_response {
> +	__u32 status;
> +	__u32 response_len;
> +};
> +
> +struct az_blob_request_sync {
> +	guid_t guid;
> +	__u32 timeout;
> +	__u32 request_len;
> +	__u32 response_len;
> +	__u32 data_len;
> +	__u32 data_valid;
> +	__aligned_u64 request_buffer;
> +	__aligned_u64 response_buffer;
> +	__aligned_u64 data_buffer;
> +	struct az_blob_request_sync_response response;
> +};
> +
> +#define AZ_BLOB_MAGIC_NUMBER	'R'
> +#define IOCTL_AZ_BLOB_DRIVER_USER_REQUEST \
> +		_IOWR(AZ_BLOB_MAGIC_NUMBER, 0xf0, \
> +			struct az_blob_request_sync)
> +
> +#endif /* define _AZ_BLOB_H */

So this driver only supports synchronous requests? Is it likely that 
users will ask for support of an API that supports having multiple 
requests outstanding at the same time without having to create multiple 
user space threads?

Thanks,

Bart.