RE: [PATCH v2 1/6] Add ancillary bus support

["Ertman, David M" <david.m.ertman@intel.com>]

> -----Original Message-----
> From: Leon Romanovsky <leon@kernel.org>
> Sent: Thursday, October 8, 2020 10:20 AM
> To: Ertman, David M <david.m.ertman@intel.com>
> Cc: alsa-devel@alsa-project.org; tiwai@suse.de; broonie@kernel.org; linux-
> rdma@vger.kernel.org; jgg@nvidia.com; dledford@redhat.com;
> netdev@vger.kernel.org; davem@davemloft.net; kuba@kernel.org;
> gregkh@linuxfoundation.org; ranjani.sridharan@linux.intel.com; pierre-
> louis.bossart@linux.intel.com; fred.oh@linux.intel.com;
> parav@mellanox.com; Saleem, Shiraz <shiraz.saleem@intel.com>; Williams,
> Dan J <dan.j.williams@intel.com>; Patil, Kiran <kiran.patil@intel.com>
> Subject: Re: [PATCH v2 1/6] Add ancillary bus support
> 
> On Mon, Oct 05, 2020 at 11:24:41AM -0700, Dave Ertman wrote:
> > Add support for the Ancillary Bus, ancillary_device and ancillary_driver.
> > It enables drivers to create an ancillary_device and bind an
> > ancillary_driver to it.
> >
> > The bus supports probe/remove shutdown and suspend/resume callbacks.
> > Each ancillary_device has a unique string based id; driver binds to
> > an ancillary_device based on this id through the bus.
> >
> > Co-developed-by: Kiran Patil <kiran.patil@intel.com>
> > Signed-off-by: Kiran Patil <kiran.patil@intel.com>
> > Co-developed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
> > Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
> > Co-developed-by: Fred Oh <fred.oh@linux.intel.com>
> > Signed-off-by: Fred Oh <fred.oh@linux.intel.com>
> > Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> > Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
> > Reviewed-by: Parav Pandit <parav@mellanox.com>
> > Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
> > ---
> 
> <...>
> 
> > +
> > +static const struct ancillary_device_id *ancillary_match_id(const struct
> ancillary_device_id *id,
> > +							    const struct
> ancillary_device *ancildev)
> > +{
> > +	while (id->name[0]) {
> > +		const char *p = strrchr(dev_name(&ancildev->dev), '.');
> > +		int match_size;
> > +
> > +		if (!p) {
> > +			id++;
> > +			continue;
> > +		}
> > +		match_size = p - dev_name(&ancildev->dev);
> > +
> > +		/* use dev_name(&ancildev->dev) prefix before last '.' char
> to match to */
> > +		if (!strncmp(dev_name(&ancildev->dev), id->name,
> match_size))
> 
> This check is wrong, it causes to wrong matching if strlen(id->name) >
> match_size
> In my case, the trigger was:
> [    5.175848] ancillary:ancillary_match_id: dev mlx5_core.ib.0, id
> mlx5_core.ib_rep

Nice catch , I will look into this.

-DaveE

> 
> From cf8f10af72f9e0d57c7ec077d59238cc12b0650f Mon Sep 17 00:00:00 2001
> From: Leon Romanovsky <leonro@nvidia.com>
> Date: Thu, 8 Oct 2020 19:40:03 +0300
> Subject: [PATCH] fixup! Fixes to ancillary bus
> 
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/bus/ancillary.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/ancillary.c b/drivers/bus/ancillary.c
> index 54858f744ef5..615ce40ef8e4 100644
> --- a/drivers/bus/ancillary.c
> +++ b/drivers/bus/ancillary.c
> @@ -31,8 +31,10 @@ static const struct ancillary_device_id
> *ancillary_match_id(const struct ancilla
>  		match_size = p - dev_name(&ancildev->dev);
> 
>  		/* use dev_name(&ancildev->dev) prefix before last '.' char
> to match to */
> -		if (!strncmp(dev_name(&ancildev->dev), id->name,
> match_size))
> +		if (match_size == strlen(id->name) &&
> !strncmp(dev_name(&ancildev->dev), id->name, match_size)) {
>  			return id;
> +		}
> +
>  		id++;
>  	}
>  	return NULL;
> --
> 2.26.2
> 
> 
> 
> > +			return id;
> > +		id++;
> > +	}
> > +	return NULL;
> > +}