On Mon, 6 Jun 2022 11:37:42 +0000 Dmitry Rokosov <DDRokosov@xxxxxxxxxxxxxx> wrote: > Hello Jonathan, > > Thank you for comments. I have a several questions about the flow, > please find them below. > > On Sat, Jun 04, 2022 at 02:59:55PM +0100, Jonathan Cameron wrote: > > On Wed, 1 Jun 2022 17:48:32 +0000 > > Dmitry Rokosov <DDRokosov@xxxxxxxxxxxxxx> wrote: > > > > > To provide a new IIO trigger to the IIO core, usually driver executes the > > > following pipeline: allocate()/register()/get(). Before, IIO core assigned > > > trig->owner as a pointer to the module which registered this trigger at > > > the register() stage. But actually the trigger object is owned by the > > > module earlier, on the allocate() stage, when trigger object is > > > successfully allocated for the driver. > > > > > > This patch moves trig->owner initialization from register() > > > stage of trigger initialization pipeline to allocate() stage to > > > eliminate all misunderstandings and time gaps between trigger object > > > creation and owner acquiring. > > > > > > Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> > > > > Hi Dmitry, > > > > I 'think' this is fine, but its in the high risk category that I'd like > > to keep it on list for a few weeks before applying. > > > > Could you please explain what it means? Do you have some testing branch > with such dangerous patches or do we need just to wait other developers > for more points of view? Thanks in advance. The second - so far I haven't applied it anywhere. > > > Note I'm still keen that in general we keep the flow such that > > we do allocate()/register()/get() as there is no guarantee that the get() > > will never do anything that requires the trigger to be registered, even > > though that is true today. Which is another way of saying I'm still > > keen we fix up any cases that sneak in after your fix up set dealt with > > the current ones. > > I fully agree with you. I suppose to resolve such a problem we need to > have some indicators that the trigger is already registered or not. > From my point of view, trig->list entry fits well to answer this question. > Trigger is added to the global IIO triggers list during register() > execution, so we can just check that entry is not empty to make sure that > trigger is registered. > > I've sent a v2 patch version, where I use trig->list entry empty status to > warn it: > > https://lore.kernel.org/linux-iio/20220606111316.19265-1-ddrokosov@xxxxxxxxxxxxxx/ Great! Jonathan > > > > > Thanks for following up on this! > > > > Jonathan > > >
