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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: kvm@vger.kernel.org, "Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind
Date: Tue, 8 Jun 2021 09:37:59 +0200	[thread overview]
Message-ID: <YL8eV9mhSNxY+1uX@kroah.com> (raw)
In-Reply-To: <4-v1-324b2038f212+1041f1-vfio3a_jgg@nvidia.com>

On Mon, Jun 07, 2021 at 09:55:46PM -0300, Jason Gunthorpe wrote:
> EPROBE_DEFER is an internal kernel error code and it should not be leaked
> to userspace via the bind_store() sysfs. Userspace doesn't have this
> constant and cannot understand it.
> 
> Further, it doesn't really make sense to have userspace trigger a deferred
> probe via bind_store(), which could eventually succeed, while
> simultaneously returning an error back.
> 
> Resolve this by preventing EPROBE_DEFER from triggering a deferred probe
> and simply relay the whole situation back to userspace as a normal -EAGAIN
> code.
> 
> Put this in the device_driver_attach() so the EPROBE_DEFER remains
> contained to dd.c and the probe() implementations.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/base/dd.c | 39 ++++++++++++++++++++++++++++-----------
>  1 file changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 7fb58e6219b255..edda7aad43a3f7 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -516,12 +516,17 @@ static DEVICE_ATTR_RO(state_synced);
>  enum {
>  	/* Set on output if the -ERR has come from a probe() function */
>  	PROBEF_DRV_FAILED = 1 << 0,
> +	/*
> +	 * Set on input to call driver_deferred_probe_add() if -EPROBE_DEFER
> +	 * is returned
> +	 */
> +	PROBEF_SCHEDULE_DEFER = 1 << 1,

I don't understand what "PROBEF" means.  Not good for something that I
am going to be forced to maintain...

Again, "flags" are horrible, but if you do have them, then they should
at least be understandable.

Please try to do this without random flag values.

thanks,

greg k-h

  parent reply	other threads:[~2021-06-08  7:38 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08  0:55 [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Jason Gunthorpe
2021-06-08  0:55 ` [Intel-gfx] " Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 01/10] driver core: Do not continue searching for drivers if deferred probe is used Jason Gunthorpe
2021-06-08  5:51   ` Christoph Hellwig
2021-06-08  6:44   ` Greg Kroah-Hartman
2021-06-08 12:16     ` Jason Gunthorpe
2021-06-08 13:13       ` Greg Kroah-Hartman
2021-06-08 13:53         ` Jason Gunthorpe
2021-06-08  7:35   ` Greg Kroah-Hartman
2021-06-08 12:17     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 02/10] driver core: Pull required checks into driver_probe_device() Jason Gunthorpe
2021-06-08  5:59   ` Christoph Hellwig
2021-06-08 12:21     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Jason Gunthorpe
2021-06-08  6:07   ` Christoph Hellwig
2021-06-08 23:53     ` Jason Gunthorpe
2021-06-08  6:47   ` Greg Kroah-Hartman
2021-06-08 12:30     ` Jason Gunthorpe
2021-06-08 13:16       ` Greg Kroah-Hartman
2021-06-08 14:03         ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during " Jason Gunthorpe
2021-06-08  6:14   ` Christoph Hellwig
2021-06-08  7:37   ` Greg Kroah-Hartman [this message]
2021-06-08  0:55 ` [PATCH 05/10] driver core: Export device_driver_attach() Jason Gunthorpe
2021-06-08  6:19   ` Christoph Hellwig
2021-06-08 12:33     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Jason Gunthorpe
2021-06-08  0:55   ` [Intel-gfx] " Jason Gunthorpe
2021-06-08  6:20   ` Christoph Hellwig
2021-06-08  6:20     ` [Intel-gfx] " Christoph Hellwig
2021-06-11 12:40   ` Cornelia Huck
2021-06-11 12:40     ` [Intel-gfx] " Cornelia Huck
2021-06-14 12:35     ` Jason Gunthorpe
2021-06-14 12:35       ` [Intel-gfx] " Jason Gunthorpe
2021-06-14 12:35       ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Jason Gunthorpe
2021-06-08  6:21   ` Christoph Hellwig
2021-06-08  0:55 ` [PATCH 08/10] vfio/mtty: Convert to use vfio_register_group_dev() Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 09/10] vfio/mdpy: " Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 10/10] vfio/mbochs: " Jason Gunthorpe
2021-06-08  6:22 ` [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Christoph Hellwig
2021-06-08  6:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-14 14:34 ` Kirti Wankhede
2021-06-14 14:34   ` [Intel-gfx] " Kirti Wankhede
2021-06-14 14:34   ` Kirti Wankhede
2021-06-14 14:36   ` Jason Gunthorpe
2021-06-14 14:36     ` [Intel-gfx] " Jason Gunthorpe
2021-06-14 14:36     ` Jason Gunthorpe
2021-06-14 15:08 Allow mdev drivers to directly create the vfio_device (v2 / alternative) Christoph Hellwig
2021-06-14 15:08 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind Christoph Hellwig
2021-06-14 22:43   ` Jason Gunthorpe
2021-06-14 22:43     ` Jason Gunthorpe
2021-06-15 13:35 Allow mdev drivers to directly create the vfio_device (v3) Christoph Hellwig
2021-06-15 13:35 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind Christoph Hellwig
2021-06-15 14:03   ` Cornelia Huck
2021-06-15 14:03     ` Cornelia Huck
2021-06-15 19:36   ` Alex Williamson
2021-06-15 19:36     ` Alex Williamson
2021-06-17 14:22 Allow mdev drivers to directly create the vfio_device (v4) Christoph Hellwig
2021-06-17 14:22 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind Christoph Hellwig

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