[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20231021165535.34dcb94b@jic23-huawei>
Date: Sat, 21 Oct 2023 16:55:35 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Matti Vaittinen <mazziesaccount@...il.com>
Cc: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
Lars-Peter Clausen <lars@...afoo.de>,
linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/2] Sanity-check available_scan_masks array
On Mon, 16 Oct 2023 14:04:11 +0300
Matti Vaittinen <mazziesaccount@...il.com> wrote:
> Sanity-check available_scan_masks array
>
> The available_scan_masks is an array of bitmasks representing the
> channels which can be simultaneously(*) scanned by a driver from the
> device. Following special characteristics apply:
>
> - When IIO is scanning through the array it will use the first mask
> which can be used to scan all enabled channels. This means drivers
> should order the array in the order of the preference. This does also
> mean that a mask which is a subset of a mask located earler in array
> will never be used because the earlier one will be picked by the core.
> - Masks wider than size of long are supported only to some extent. The
> code scanning through the array will interpret the first mask with
> first long zeroed as end-of-array terminator. Changing this behaviour
> would make mask-arrays for multi-long masks to be terminated by more
> than one zero long. Failure to do so would result kernel to read
> beyond the array generating a potentially hazardous bug.
>
> Add a sanity-check to IIO-device registration emitting a warning if
> available_scan_mask array is misordered or if mask width is larger than
> a long while available_scan_mask-array is populated. Currently there
> should be no in-tree drivers with available_scan_mask populated and mask
> wider than a long.
>
> Revision history:
> v1 => v2:
> - Add patch 2/2 documenting why iio_scan_mask_match() checks only
> a long worth of bits while searching for the end of the
> available_scan_mask-array.
> - Styling of patch 1/2 as per comments from Jonathan
> v1 and related discussion here:
> https://lore.kernel.org/lkml/ZRvjuZaQWdZw1U1I@dc78bmyyyyyyyyyyyyydt-3.rev.dnainternet.fi/
>
> Matti Vaittinen (2):
> iio: sanity check available_scan_masks array
> iio: buffer: document known issue
>
> drivers/iio/industrialio-buffer.c | 16 ++++++++
> drivers/iio/industrialio-core.c | 63 +++++++++++++++++++++++++++++++
> 2 files changed, 79 insertions(+)
>
Hi Matti,
Just a quick note to say this looks fine to me, but I don't want to queue it up
just yet given proximity to merge window etc. I'll aim to pick it up early
in next cycle. Give me a poke if I still haven't by rc3 or so.
Thanks,
Jonathan
Powered by blists - more mailing lists