Re: [PATCH 0/6] Trigger locking rework and splitting up trigger.h

[Jonathan Cameron <jic23@cam.ac.uk>]

Hi All,

This set have been around for a while. I've not seen any issues yet
and no one has screamed so I'll probably assume they are fine and send
on to Greg shortly.

Michael, you've been testing on the iio-blue.git tree which has these.
Any sign of problems yet?

Thanks,

Jonathan
> This is the result of actually checking the locking code for
> triggers and ensuring saferemoval.
> 
> One kicker in here.  Any driver that can do dynamic creation / removal
> of triggers (currently only sysfs trigger), must be very very careful.
> It's possible post this series for two devices to apparently be connected
> to a trigger with the same name, but only one be connected to the current
> instance of that trigger.  To my mind, if you've got into this mess, your
> userspace is borked anyway and it doesn't actually cause a crash (unlike
> before this set), it just doesn't work as expected.
> 
> If anyone can see a case I've missed, please do point it out.
> 
> Note this also includes the trigger.h split and the semantic change
> discussed in 'Splitting trigger header in two and barriers'.
> 
> That is, if your driver is currently using a trigger (other than one
> it provides), you will not be able to remove the module.  The previous
> approach of just disconnected on removal would double release some stuff
> anyway causing lots of unpleasant messages.
> 
> Whilst this stuff is definitely broken in current mainline, I'm not
> proposing to rush this set out.
> 
> Thanks,
> 
> Jonathan
> 
> Jonathan Cameron (6):
>   staging:iio:triggers reorder module put and device put to ensure that
>         the ops are still there if put results in device deletion.
>   staging:iio:trigger:sysfs trigger: Add a release function to avoid
>     warning     on module removal.
>   staging:iio:pollfunc: Make explicit that private data is always
>     pointer to a struct iio_dev.
>   staging:iio: prevent removal of module connected to trigger.
>   staging:iio:rename trigger_consumer.h to indicate it is core only.
>   staging:iio: spit trigger.h into provider and consumer parts.
> 
>  drivers/staging/iio/accel/adis16201_ring.c   |    4 +-
>  drivers/staging/iio/accel/adis16203_ring.c   |    4 +-
>  drivers/staging/iio/accel/adis16204_ring.c   |    4 +-
>  drivers/staging/iio/accel/adis16209_ring.c   |    4 +-
>  drivers/staging/iio/accel/adis16240_ring.c   |    4 +-
>  drivers/staging/iio/accel/lis3l02dq_ring.c   |    3 +-
>  drivers/staging/iio/adc/ad7298_ring.c        |    9 +---
>  drivers/staging/iio/adc/ad7476_ring.c        |   10 +---
>  drivers/staging/iio/adc/ad7606_ring.c        |   10 +---
>  drivers/staging/iio/adc/ad7793.c             |    9 +---
>  drivers/staging/iio/adc/ad7887_ring.c        |   10 +---
>  drivers/staging/iio/adc/ad799x_ring.c        |   10 +---
>  drivers/staging/iio/adc/max1363_ring.c       |    9 +---
>  drivers/staging/iio/gyro/adis16260_ring.c    |    4 +-
>  drivers/staging/iio/iio_core_trigger.h       |   47 +++++++++++++++++
>  drivers/staging/iio/imu/adis16400_ring.c     |    4 +-
>  drivers/staging/iio/industrialio-core.c      |    2 +-
>  drivers/staging/iio/industrialio-trigger.c   |    8 ++-
>  drivers/staging/iio/meter/ade7758_ring.c     |   10 +---
>  drivers/staging/iio/trigger.h                |   46 +----------------
>  drivers/staging/iio/trigger/iio-trig-sysfs.c |    7 +++
>  drivers/staging/iio/trigger_consumer.h       |   71 ++++++++++++++------------
>  22 files changed, 134 insertions(+), 155 deletions(-)
>  create mode 100644 drivers/staging/iio/iio_core_trigger.h
>