Patch series "mm: ioremap: Convert architectures to take GENERIC_IOREMAP
way", v8.
Motivation and implementation:
==============================
Currently, many architecutres have't taken the standard GENERIC_IOREMAP
way to implement ioremap_prot(), iounmap(), and ioremap_xx(), but make
these functions specifically under each arch's folder. Those cause many
duplicated code of ioremap() and iounmap().
In this patchset, firstly introduce generic_ioremap_prot() and
generic_iounmap() to extract the generic code for GENERIC_IOREMAP. By
taking GENERIC_IOREMAP method, the generic generic_ioremap_prot(),
generic_iounmap(), and their generic wrapper ioremap_prot(), ioremap() and
iounmap() are all visible and available to arch. Arch needs to provide
wrapper functions to override the generic version if there's arch specific
handling in its corresponding ioremap_prot(), ioremap() or iounmap().
With these changes, duplicated ioremap/iounmap() code uder ARCH-es are
removed, and the equivalent functioality is kept as before.
Background info:
================
1) The converting more architectures to take GENERIC_IOREMAP way is
suggested by Christoph in below discussion:
https://lore.kernel.org/all/Yp7h0Jv6vpgt6xdZ@infradead.org/T/#u
2) In the previous v1 to v3, it's basically further action after arm64
has converted to GENERIC_IOREMAP way in below patchset. It's done by
adding hook ioremap_allowed() and iounmap_allowed() in ARCH to add ARCH
specific handling the middle of ioremap_prot() and iounmap().
[PATCH v5 0/6] arm64: Cleanup ioremap() and support ioremap_prot()
https://lore.kernel.org/all/20220607125027.44946-1-wangkefeng.wang@huawei.com/T/#u
Later, during v3 reviewing, Christophe Leroy suggested to introduce
generic_ioremap_prot() and generic_iounmap() to generic codes, and ARCH
can provide wrapper function ioremap_prot(), ioremap() or iounmap() if
needed. Christophe made a RFC patchset as below to specially demonstrate
his idea. This is what v4 and now v5 is doing.
[RFC PATCH 0/8] mm: ioremap: Convert architectures to take GENERIC_IOREMAP way
https://lore.kernel.org/all/cover.1665568707.git.christophe.leroy@csgroup.eu/T/#u
Testing:
========
In v8, I only applied this patchset onto the latest linus's tree to build
and run on arm64 and s390.
This patch (of 19):
Let's use '#define ioremap_xx' and "#ifdef ioremap_xx" instead.
To remove defined ARCH_HAS_IOREMAP_xx macros in <asm/io.h> of each ARCH,
the ARCH's own ioremap_wc|wt|np definition need be above "#include
<asm-generic/iomap.h>. Otherwise the redefinition error would be seen
during compiling. So the relevant adjustments are made to avoid compiling
error:
loongarch:
- doesn't include <asm-generic/iomap.h>, defining ARCH_HAS_IOREMAP_WC
is redundant, so simply remove it.
m68k:
- selected GENERIC_IOMAP, <asm-generic/iomap.h> has been added in
<asm-generic/io.h>, and <asm/kmap.h> is included above
<asm-generic/iomap.h>, so simply remove ARCH_HAS_IOREMAP_WT defining.
mips:
- move "#include <asm-generic/iomap.h>" below ioremap_wc definition
in <asm/io.h>
powerpc:
- remove "#include <asm-generic/iomap.h>" in <asm/io.h> because it's
duplicated with the one in <asm-generic/io.h>, let's rely on the
latter.
x86:
- selected GENERIC_IOMAP, remove #include <asm-generic/iomap.h> in
the middle of <asm/io.h>. Let's rely on <asm-generic/io.h>.
Link: https://lkml.kernel.org/r/20230706154520.11257-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Helge Deller <deller@gmx.de>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
0b1f77e74b