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From: Matthew Wilcox <willy@infradead.org>
To: Wei Liu <wei.liu@kernel.org>
Cc: Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
	virtualization@lists.linux-foundation.org,
	Linux Kernel List <linux-kernel@vger.kernel.org>,
	Michael Kelley <mikelley@microsoft.com>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	Sunil Muthuswamy <sunilmut@microsoft.com>,
	Nuno Das Neves <nunodasneves@linux.microsoft.com>,
	kumarpraveen@linux.microsoft.com, pasha.tatashin@soleen.com,
	Jonathan Corbet <corbet@lwn.net>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Dexuan Cui <decui@microsoft.com>,
	Lillian Grassin-Drake <ligrassi@microsoft.com>,
	Muminul Islam <muislam@microsoft.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>
Subject: Re: [RFC v1 7/8] mshv: implement in-kernel device framework
Date: Fri, 9 Jul 2021 16:32:48 +0100	[thread overview]
Message-ID: <YOhsIDccgbUCzwqt@casper.infradead.org> (raw)
In-Reply-To: <20210709135013.t5axinjmufotpylf@liuwe-devbox-debian-v2>

On Fri, Jul 09, 2021 at 01:50:13PM +0000, Wei Liu wrote:
> On Fri, Jul 09, 2021 at 02:02:04PM +0100, Matthew Wilcox wrote:
> > On Fri, Jul 09, 2021 at 11:43:38AM +0000, Wei Liu wrote:
> > > +static long
> > > +mshv_partition_ioctl_create_device(struct mshv_partition *partition,
> > > +	void __user *user_args)
> > > +{
> > [...]
> > > +	mshv_partition_get(partition);
> > > +	r = anon_inode_getfd(ops->name, &mshv_device_fops, dev, O_RDWR | O_CLOEXEC);
> > > +	if (r < 0) {
> > > +		mshv_partition_put_no_destroy(partition);
> > > +		list_del(&dev->partition_node);
> > > +		ops->destroy(dev);
> > > +		goto out;
> > > +	}
> > > +
> > > +	cd->fd = r;
> > > +	r = 0;
> > 
> > Why return the fd in memory instead of returning the fd as the return
> > value from the ioctl?
> > 
> > > +	if (copy_to_user(user_args, &tmp, sizeof(tmp))) {
> > > +		r = -EFAULT;
> > > +		goto out;
> > > +	}
> > 
> > ... this could then disappear.
> 
> Thanks for your comment, Matthew.
> 
> This is intentionally because I didn't want to deviate from KVM's API.
> The fewer differences the better.

Then don't define your own structure.  Use theirs.

  reply	other threads:[~2021-07-09 15:33 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 11:43 [RFC v1 0/8] MSHV: add PV-IOMMU driver Wei Liu
2021-07-09 11:43 ` [RFC v1 1/8] x86/hyperv: export hv_build_pci_dev_id Wei Liu
2021-07-09 11:43 ` [RFC v1 2/8] asm-generic/hyperv: add device domain definitions Wei Liu
2021-07-09 11:43 ` [RFC v1 3/8] intel/vt-d: make DMAR table parsing code more flexible Wei Liu
2021-07-09 12:56   ` Robin Murphy
2021-07-09 13:42     ` Wei Liu
2021-07-09 11:43 ` [RFC v1 4/8] intel/vt-d: export intel_iommu_get_resv_regions Wei Liu
2021-07-09 14:17   ` Lu Baolu
2021-07-09 14:21     ` Wei Liu
2021-07-09 11:43 ` [RFC v1 5/8] mshv: add paravirtualized IOMMU support Wei Liu
2021-08-03 18:40   ` Praveen Kumar
2021-08-03 21:47     ` Wei Liu
2021-08-04  6:43       ` Praveen Kumar
2021-08-10 10:46         ` Wei Liu
2021-07-09 11:43 ` [RFC v1 6/8] mshv: command line option to skip devices in PV-IOMMU Wei Liu
2021-07-09 12:46   ` Robin Murphy
2021-07-09 13:34     ` Wei Liu
2021-08-03 18:50   ` Praveen Kumar
2021-08-03 21:56     ` Wei Liu
2021-08-04  7:03       ` Praveen Kumar
2021-08-10 10:04         ` Wei Liu
2021-07-09 11:43 ` [RFC v1 7/8] mshv: implement in-kernel device framework Wei Liu
2021-07-09 13:02   ` Matthew Wilcox
2021-07-09 13:50     ` Wei Liu
2021-07-09 15:32       ` Matthew Wilcox [this message]
2021-07-09 16:27         ` Wei Liu
2021-07-09 16:38           ` Matthew Wilcox
2021-07-09 19:14             ` Wei Liu
2021-07-09 19:48               ` Matthew Wilcox
2021-07-09 20:11                 ` Wei Liu
2021-08-03 19:12   ` Praveen Kumar
2021-08-03 22:04     ` Wei Liu
2021-07-09 11:43 ` [RFC v1 8/8] mshv: add vfio bridge device Wei Liu
2021-08-03 19:27   ` Praveen Kumar
2021-08-10 10:52     ` Wei Liu

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