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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Christoph Hellwig <hch@lst.de>
Cc: kvm@vger.kernel.org, linux-doc@vger.kernel.org,
	David Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org,
	Kirti Wankhede <kwankhede@nvidia.com>,
	linux-s390@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Halil Pasic <pasic@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Jason Gunthorpe <jgg@nvidia.com>,
	intel-gfx@lists.freedesktop.org,
	Jason Herne <jjherne@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Tony Krowiak <akrowiak@linux.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH 01/10] driver core: Pull required checks into driver_probe_device()
Date: Tue, 15 Jun 2021 07:16:07 +0200	[thread overview]
Message-ID: <YMg3l5jsSz0OabNK@kroah.com> (raw)
In-Reply-To: <20210614150846.4111871-2-hch@lst.de>

On Mon, Jun 14, 2021 at 05:08:37PM +0200, Christoph Hellwig wrote:
> From: Jason Gunthorpe <jgg@nvidia.com>
> 
> Checking if the dev is dead or if the dev is already bound is a required
> precondition to invoking driver_probe_device(). All the call chains
> leading here duplicate these checks.
> 
> Add it directly to driver_probe_device() so the precondition is clear and
> remove the checks from device_driver_attach() and
> __driver_attach_async_helper().
> 
> The other call chain going through __device_attach_driver() does have
> these same checks but they are inlined into logic higher up the call stack
> and can't be removed.
> 
> The sysfs uAPI call chain starting at bind_store() is a bit confused
> because it reads dev->driver unlocked and returns -ENODEV if it is !NULL,
> otherwise it reads it again under lock and returns 0 if it is !NULL. Fix
> this to always return -EBUSY and always read dev->driver under its lock.
> 
> Done in preparation for the next patches which will add additional
> callers to driver_probe_device() and will need these checks as well.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> [hch: drop the extra checks in device_driver_attach and bind_store]
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

  parent reply	other threads:[~2021-06-15  5:16 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210614150846.4111871-1-hch@lst.de>
     [not found] ` <20210614150846.4111871-5-hch@lst.de>
2021-06-14 22:43   ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind Jason Gunthorpe
     [not found] ` <20210614150846.4111871-2-hch@lst.de>
2021-06-15  5:16   ` Greg Kroah-Hartman [this message]
2021-06-15 10:27   ` [PATCH 01/10] driver core: Pull required checks into driver_probe_device() Cornelia Huck
     [not found] ` <20210614150846.4111871-3-hch@lst.de>
2021-06-14 18:47   ` [PATCH 02/10] driver core: Better distinguish probe errors in really_probe Kirti Wankhede
2021-06-15  5:17   ` Greg Kroah-Hartman
2021-06-15  5:21 ` Allow mdev drivers to directly create the vfio_device (v2 / alternative) Greg Kroah-Hartman
     [not found]   ` <20210615055021.GB21080@lst.de>
2021-06-15 15:27     ` Jason Gunthorpe
     [not found] ` <20210614150846.4111871-4-hch@lst.de>
2021-06-15  5:18   ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Greg Kroah-Hartman
2021-06-15 10:31   ` Cornelia Huck
     [not found] ` <20210614150846.4111871-6-hch@lst.de>
2021-06-15  5:20   ` [PATCH 05/10] driver core: Export device_driver_attach() Greg Kroah-Hartman
2021-06-15 10:49   ` Cornelia Huck
     [not found] ` <20210614150846.4111871-7-hch@lst.de>
2021-06-15 10:50   ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Cornelia Huck
     [not found] ` <20210614150846.4111871-8-hch@lst.de>
2021-06-15 10:54   ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Cornelia Huck

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