-----Original Message-----
From: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Sent: Tuesday, December 7, 2021 2:52 PM
To: David S . Miller <davem@davemloft.net>; Jakub Kicinski
[off-list ref]
Cc: netdev@vger.kernel.org; Kumar, M Chetan
[off-list ref]; linuxwwan [off-list ref]; Loic
Poulain [off-list ref]; Johannes Berg
[off-list ref]; Leon Romanovsky [off-list ref]
Subject: [PATCH RESEND net-next v2 0/4] WWAN debugfs tweaks

Resent after dependency [2] was merged to the net-next tree. Added Leon's
reviewed-by tag from the first V2 submission.

This is a follow-up series to just applied IOSM (and WWAN) debugfs interface
support [1]. The series has two main goals:
1. move the driver-specific debugfs knobs to a subdirectory; 2. make the
debugfs interface optional for both IOSM and for the WWAN
   core.

As for the first part, I must say that it was my mistake. I suggested to place
debugfs entries under a common per WWAN device directory. But I missed
the driver subdirectory in the example, so it become:

/sys/kernel/debugfs/wwan/wwan0/trace

Since the traces collection is a driver-specific feature, it is better to keep it
under the driver-specific subdirectory:

/sys/kernel/debugfs/wwan/wwan0/iosm/trace

It is desirable to be able to entirely disable the debugfs interface. It can be
disabled for several reasons, including security and consumed storage space.
See detailed rationale with usage example in the 4th patch.

The changes themselves are relatively simple, but require a code
rearrangement. So to make changes clear, I chose to split them into
preparatory and main changes and properly describe each of them.

IOSM part is compile-tested only since I do not have IOSM supported device,
so it needs Ack from the driver developers.

I would like to thank Johannes Berg and Leon Romanovsky. Their suggestions
and comments helped a lot to rework the initial over-engineered solution to
something less confusing and much more simple. Thanks!

Changes since v1:
* 1st and 2nd patches were not changed
* add missed field description in the 3rd patch
* 4th and 5th patches have been merged into a single one with rework of
  the configuration options and and a few other fixes (see detailed
  changelog in the patch)

1. https://lore.kernel.org/netdev/20211120162155.1216081-1-
m.chetan.kumar@linux.intel.com
2.
https://patchwork.kernel.org/project/netdevbpf/patch/20211204174033.950
528-1-arnd@kernel.org/

Acked-by: M Chetan Kumar <redacted>