On Sat, 21 Oct 2023 19:03:15 +0300 Matti Vaittinen <mazziesaccount@xxxxxxxxx> wrote: > On 10/21/23 18:55, Jonathan Cameron wrote: > > On Mon, 16 Oct 2023 14:04:11 +0300 > > Matti Vaittinen <mazziesaccount@xxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > >> > >> 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. > > Makes perfect sense to me. > > > I'll aim to pick it up early > > in next cycle. Give me a poke if I still haven't by rc3 or so. > > Ouch... My memory gets worse year by year - well, I'll try to remember :) I've started queuing stuff up for rebasing post merge window, so I've added this as well. For now will only be exposed as the testing branch that 0-day pokes at. Thanks, Jonathan > > Yours, > -- Matti >
