lkml.org 
[lkml]   [2022]   [Jun]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [v6 08/14] iio: imu: add Bosch Sensortec BNO055 core driver
    Il giorno mar 14 giu 2022 alle ore 17:11 Andy Shevchenko
    <andy.shevchenko@gmail.com> ha scritto:
    >
    > On Tue, Jun 14, 2022 at 2:15 PM Andrea Merello <Andrea.Merello@iit.it> wrote:
    >
    > ...
    >
    > > >> >> + devm_add_action_or_reset(priv->dev, bno055_debugfs_remove, priv->debugfs);
    > > >> >
    > > >> >Shouldn't we report the potential error here? It's not directly
    > > >> >related to debugfs, but something which is not directly related.
    > > >>
    > > >> The error eventually comes out from something that has nothing to do with debugs per se (i.e. the devm stuff), but it will only affect debugfs indeed.
    > > >>
    > > >> Assuming that we don't want to make the whole driver fail in case debugfs stuff fails (see last part of the comment above debugfs_create_file() implementation), and given that the devm_add_action_or_reset(), should indeed "reset" in case of failure (i.e. we should be in a clean situation anyway), I would say it should be OK not to propagate the error and let things go on.
    > > >
    > > >As I said, it's not directly related to debugfs. Here is the resource
    > > >leak possible or bad things happen if you probe the driver, that fails
    > > >to add this call for removal, remove it, and try to insert again, in
    > > >such case the debugfs will be stale.
    > >
    > > Hum, I would say this shouldn't ever happen: AFAICS devm_add_action_or_reset() is a wrapper around devm_add_action() and it's purpose is exactly to add a check for failure; devm_add_action_or_reset() immediately invokes the action handler in case devm_add_action() fails. IOW in case of failure to add the devm stuff, the debugfs file is removed immediately and it shouldn't cause any mess with next times probe()s; just the driver will go on without the debugfs file being here.
    > >
    > > I think this is the point of using devm_add_action_or_reset() instead of dev_add_action() indeed, or am I missing something?
    >
    > Reading that code again and I think you are right, so dev_warn() will
    > be sufficient to show that we fail. OTOH, what is the point of adding
    > a resource for the failed debugfs call?

    Ah, you are right here: I'll make the call to
    devm_add_action_or_reset() conditional to success of
    debugfs_create_file(). In case any of the two fails we can also warn
    the user.

    > --
    > With Best Regards,
    > Andy Shevchenko

    \
     
     \ /
      Last update: 2022-06-14 17:29    [W:2.994 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site