Merge tags 'block-ioctl-cleanup-5.6' and 'y2038-drivers-for-v5.6-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground into y2038-for-v5.6

block, scsi: final compat_ioctl cleanup

This series concludes the work I did for linux-5.5 on the compat_ioctl()
cleanup, killing off fs/compat_ioctl.c and block/compat_ioctl.c by moving
everything into drivers.

Overall this would be a reduction both in complexity and line count, but
as I'm also adding documentation the overall number of lines increases
in the end.

My plan was originally to keep the SCSI and block parts separate.
This did not work easily because of interdependencies: I cannot
do the final SCSI cleanup in a good way without first addressing the
CDROM ioctls, so this is one series that I hope could be merged through
either the block or the scsi git trees, or possibly both if you can
pull in the same branch.

The series comes in these steps:

1. clean up the sg v3 interface as suggested by Linus. I have
   talked about this with Doug Gilbert as well, and he would
   rebase his sg v4 patches on top of "compat: scsi: sg: fix v3
   compat read/write interface"

2. Actually moving handlers out of block/compat_ioctl.c and
   block/scsi_ioctl.c into drivers, mixed in with cleanup
   patches

3. Document how to do this right. I keep getting asked about this,
   and it helps to point to some documentation file.

The branch is based on another one that fixes a couple of bugs found
during the creation of this series.

Changes since the original version [1]:

- move out the bugfixes into a branch for itself
- clean up scsi sg driver further as suggested by Christoph Hellwig
- avoid some ifdefs by moving compat_ptr() out of asm/compat.h
- split out the blkdev_compat_ptr_ioctl function; bug spotted by
  Ben Hutchings
- Fix an bisection problem also found by Ben Hutchings
- Improve formatting of documentation

[1] https://lore.kernel.org/linux-block/20191211204306.1207817-1-arnd@arndb.de/T/#m9f89df30565fc66abbded5d01f4db553b16f129f

y2038: driver and file system changes

These are updates to device drivers and file systems that for some
reason or another were not included in the kernel in the previous
y2038 series.

I've gone through all users of time_t again to make sure the
kernel is in a long-term maintainable state.

Posting these as a series for better organization, but each change
here is applicable standalone.

Please merge, review, ack/nack etc as you see fit. I will
add these to my y2038 branch [1] for linux-next, but can keep
rebasing for feedback and to remove any patches that get
picked up by a maintainer.

Changes since v1 [2]:

- Add Acks I received
- Rebase to v5.5-rc1, droping patches that got merged already
- Add NFS, XFS and the final three patches from another series
- Rewrite etnaviv patches

      Arnd

[1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git/log/?h=y2038
[2] https://lore.kernel.org/lkml/20191108213257.3097633-1-arnd@arndb.de/