RE: [Patch v4 2/3] Drivers: hv: add Azure Blob driver

From: Long Li <longli@microsoft.com>
To: Jiri Slaby <jirislaby@kernel.org>,
	"longli@linuxonhyperv.com" <longli@linuxonhyperv.com>,
	"linux-fs@vger.kernel.org" <linux-fs@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
	KY 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>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	Maximilian Luz <luzmaximilian@gmail.com>,
	Mike Rapoport <rppt@kernel.org>,
	Ben Widawsky <ben.widawsky@intel.com>,
	Andra Paraschiv <andraprs@amazon.com>,
	Siddharth Gupta <sidgup@codeaurora.org>,
	Hannes Reinecke <hare@suse.de>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Subject: RE: [Patch v4 2/3] Drivers: hv: add Azure Blob driver
Date: Tue, 20 Jul 2021 22:12:18 +0000	[thread overview]
Message-ID: <BY5PR21MB15069D0519AD92773355FCF6CEE29@BY5PR21MB1506.namprd21.prod.outlook.com> (raw)
In-Reply-To: <90ed52d3-5095-9789-53f0-477ba70edc3b@kernel.org>

> Subject: Re: [Patch v4 2/3] Drivers: hv: add Azure Blob driver
> 
> On 20. 07. 21, 5:31, longli@linuxonhyperv.com wrote:
> > --- /dev/null
> > +++ b/include/uapi/misc/hv_azure_blob.h
> > @@ -0,0 +1,34 @@
> > +/* 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/kernel.h>
> > +#include <linux/uuid.h>
> 
> Quoting from
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.
> kernel.org%2Flinux-
> doc%2FMWHPR21MB159375586D810EC5DCB66AF0D7039%40MWHPR21MB1
> 593.namprd21.prod.outlook.com%2F&amp;data=04%7C01%7Clongli%40micr
> osoft.com%7C7fdf2d6ed15d4d4122a308d94b6eeed0%7C72f988bf86f141af91
> ab2d7cd011db47%7C1%7C0%7C637623762292949381%7CUnknown%7CTWFp
> bGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVC
> I6Mn0%3D%7C3000&amp;sdata=kv0ZkU1QL6TxlJJZEQEsT7aqLFL9lmP2SStz8k
> U5sIs%3D&amp;reserved=0:
> =====
> Seems like a #include of asm/ioctl.h (or something similar) is needed so that
> _IOWR is defined.  Also, a #include is needed for __u32, __aligned_u64,
> guid_t, etc.
> =====

The user-space code includes "sys/ioctl.h" for calling into ioctl(). "sys/ioctl.h"
includes <linux/ioctl.h>, so it has no problem finding _IOWR.

guid_t is defined in <uapi/linux/uuid.h>, included from <linux/uuid.h> (in this file)
__u32 and __aligned_u64 are defined in <uapi/linux/types.>, which is included from <linux/kernel.h> (in this file)

> 
> Why was no include added?
> 
> > +
> > +/* 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 */
> >
> 
> thanks,
> --
> js
> suse labs