[PATCH 0/9] gpio: batch #1: remove modular usage from non-modular drivers

From: Paul Gortmaker
Date: Sun Mar 27 2016 - 11:46:00 EST


For GPIO, I've divided up the the audit of modular usage in non-modular
drivers into three categories to ease review and limit the batch size.
The breakdown of the three groups is as follows:

1) just replacement of modular macros with their non-modular equivalents
that CPP would have inserted anyway ; this means runtime equivalence
and actually also binary equivalence.

[This lot represents #1, which are essentially the "free" ones that have
essentially zero impact beyond the original desired cleanup goal itself.]

2) as per #1 but also with the removal of unused/orphaned __exit functions
that could never be called/exercised. This also maintains runtime
equivalence, but since the unused __exit function is gone, there is a
reduction in the object file size and hence not binary equivalence, eg:
before: -rw-rw-r-- 1 8828 drivers/gpio/gpio-rc5t583.o
after: -rw-rw-r-- 1 7396 drivers/gpio/gpio-rc5t583.o

3) as per #2 but also with the removal of a ".remove" function that is
hooked into the driver struct. This ".remove" function would of
course not be called from the __exit function since that is never run.
However in theory, someone could have triggered it via sysfs unbind,
even though there isn't a sensible use case for doing so. So to cover
that possibility, we've also disabled sysfs unbind in these drivers.

I will send #2 once this #1 is finalized/merged and #3 once #2 is merged.

For anyone new to the underlying goal of this cleanup, we are trying to
not use module support for code that can never be built as a module since:

(1) it is easy to accidentally write unused module_exit and remove code
(2) it can be misleading when reading the source, thinking it can be
modular when the Makefile and/or Kconfig prohibit it
(3) it requires the include of the module.h header file which in turn
includes nearly everything else, thus adding to CPP overhead.
(4) it gets copied/replicated into other code and spreads like weeds.

Build tested for arm and arm64 on 4.6-rc1 to ensure no silly typos exist.

Paul.
---

Cc: Alexandre Courbot <gnurou@xxxxxxxxx>
Cc: Baruch Siach <baruch@xxxxxxxxxx>
Cc: bcm-kernel-feedback-list@xxxxxxxxxxxx
Cc: Feng Kan <fkan@xxxxxxx>
Cc: Jonas Jensen <jonas.jensen@xxxxxxxxx>
Cc: Jun Nie <jun.nie@xxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Ray Jui <rjui@xxxxxxxxxxxx>
Cc: Wu Guoxing <b39297@xxxxxxxxxxxxx>
Cc: linux-gpio@xxxxxxxxxxxxxxx

Paul Gortmaker (9):
drivers/gpio: make gpio-bcm-kona.c explicitly non-modular
drivers/gpio: make gpio-mb86s7x.c driver explicitly non-modular
drivers/gpio: make gpio-mc9s08dz60.c explicitly non-modular
drivers/gpio: make gpio-moxart.c explicitly non-modular
drivers/gpio: make gpio-mvebu.c explicitly non-modular
drivers/gpio: make gpio-pl061.c explicitly non-modular
drivers/gpio: make gpio-sta2x11.c explicitly non-modular
drivers/gpio: make gpio-xgene.c explicitly non-modular
drivers/gpio: make gpio-zx.c explicitly non-modular

drivers/gpio/gpio-bcm-kona.c | 14 +++++---------
drivers/gpio/gpio-mb86s7x.c | 8 +-------
drivers/gpio/gpio-mc9s08dz60.c | 12 ++----------
drivers/gpio/gpio-moxart.c | 7 +------
drivers/gpio/gpio-mvebu.c | 5 ++---
drivers/gpio/gpio-pl061.c | 12 ++++--------
drivers/gpio/gpio-sta2x11.c | 8 ++------
drivers/gpio/gpio-xgene.c | 9 +--------
drivers/gpio/gpio-zx.c | 14 ++++++--------
9 files changed, 24 insertions(+), 65 deletions(-)

--
2.6.1