linux-kernel - [PATCH 0/3] phy: remove needless usage of module header

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Date:   Sun, 9 Dec 2018 19:34:47 -0500
From:   Paul Gortmaker <paul.gortmaker@...driver.com>
To:     Kishon Vijay Abraham I <kishon@...com>
CC:     <linux-kernel@...r.kernel.org>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Andrew Lunn <andrew@...n.ch>,
        Gregory CLEMENT <gregory.clement@...e-electrons.com>
Subject: [PATCH 0/3] phy: remove needless usage of module header

The most important thing to note here, is these clean-ups make no
changes to the final generated run-time.  The 1st commit removes an
unused function, otherwise the generated objects are also unchanged.

The work here represents a scan over the phy dir, looking for files
that have nothing to do with a modular use case, but are using modular
infrastructure regardless.

We are trying to make driver code consistent with the Makefiles/Kconfigs
that control them.  This means not using modular functions/macros for
drivers that can never be built as a module.  This has been done in quite
a lot of other mainline subsystem dirs already.

Using modular infrastructure in non-modules might seem harmless, but some
of the downfalls this leads to are:

 (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 drivers and spreads quickly.

As a data point for #3 above, an empty C file that just includes the
module.h header generates over 750kB of CPP output.  Repeating the same
experiment with init.h and the result is less than 12kB; with export.h
it is only about 1/2kB; with both it still is less than 12kB.

Build tested on x86-64 and ARM-64.

Paul.
---

Cc: Andrew Lunn <andrew@...n.ch>
Cc: Gregory CLEMENT <gregory.clement@...e-electrons.com>
Cc: Kishon Vijay Abraham I <kishon@...com>

Paul Gortmaker (3):
  phy: make phy-core explicitly non-modular
  phy: make phy-mvebu-sata explicitly non-modular
  phy: make phy-armada375-usb2 explicitly non-modular

 drivers/phy/marvell/phy-armada375-usb2.c |  8 +-------
 drivers/phy/marvell/phy-mvebu-sata.c     |  9 ++-------
 drivers/phy/phy-core.c                   | 12 +-----------
 3 files changed, 4 insertions(+), 25 deletions(-)

-- 
2.7.4