[v3,0/9] Unify hugetlb into arch_get_unmapped_area functions

Message

Oscar Salvador Sept. 10, 2024, 8 a.m. UTC

rfc -> v1: Fix s390 compilation errors
           Tested on s390
v1  -> v2: Rebased on top of mm-unstable
           Fix sparc64 compilation errors
v2  -> v3: Rebased on top of mm-unstable
           Fix bug reported by Lorenzo Stoakes


This is an attempt to get rid of a fair amount of duplicated code
wrt. hugetlb and *get_unmapped_area* functions.

HugeTLB registers a .get_unmapped_area function which gets called from
__get_unmapped_area().
hugetlb_get_unmapped_area() is defined by a bunch of architectures and
it also has a generic definition for those that do not define it.
Short-long story is that there is a ton of duplicated code between
specific hugetlb *_get_unmapped_area_* functions and mm-core functions,
so we can do better by teaching arch_get_unmapped_area* functions how
to deal with hugetlb mappings.

Note that not a lot of things need to be taught though.
hugetlb_get_unmapped_area, that gets called for hugetlb mappings,
runs some sanity checks prior to calling mm_get_unmapped_area_vmflags(),
so we do not need to that down the road in the respective
{generic,arch}_get_unmapped_area* functions.

More information can be found in the respective patches.

LTP mmapstress hugetlb selftests were ran succesfully on:

- arm64
- powerpc64
- s390
- x86_64

Oscar Salvador (9):
  mm/mmap: Teach generic_get_unmapped_area{_topdown} to handle hugetlb
    mappings
  arch/s390: Teach arch_get_unmapped_area{_topdown} to handle hugetlb
    mappings
  arch/x86: Teach arch_get_unmapped_area_vmflags to handle hugetlb
    mappings
  arch/sparc: Teach arch_get_unmapped_area{_topdown} to handle hugetlb
    mappings
  arch/powerpc: Teach book3s64 arch_get_unmapped_area{_topdown} to
    handle hugetlb mappings
  mm: Make hugetlb mappings go through mm_get_unmapped_area_vmflags
  mm: Drop hugetlb_get_unmapped_area{_*} functions
  arch/s390: Clean up hugetlb definitions
  mm: Consolidate common checks in hugetlb_get_unmapped_area

 arch/loongarch/include/asm/hugetlb.h |   4 -
 arch/mips/include/asm/hugetlb.h      |   4 -
 arch/parisc/include/asm/hugetlb.h    |  15 ----
 arch/parisc/mm/hugetlbpage.c         |  21 ------
 arch/powerpc/mm/book3s64/slice.c     |  50 ++++++++-----
 arch/s390/include/asm/hugetlb.h      |  73 ++++--------------
 arch/s390/mm/hugetlbpage.c           |  85 ---------------------
 arch/s390/mm/mmap.c                  |   9 ++-
 arch/sh/include/asm/hugetlb.h        |  15 ----
 arch/sparc/kernel/sys_sparc_32.c     |  17 ++++-
 arch/sparc/kernel/sys_sparc_64.c     |  37 +++++++--
 arch/sparc/mm/hugetlbpage.c          | 108 ---------------------------
 arch/x86/kernel/sys_x86_64.c         |  24 ++++--
 arch/x86/mm/hugetlbpage.c            | 101 -------------------------
 fs/hugetlbfs/inode.c                 |  94 +++--------------------
 include/asm-generic/hugetlb.h        |  15 ++--
 include/linux/hugetlb.h              |  22 +++---
 mm/mmap.c                            |   4 +
 18 files changed, 145 insertions(+), 553 deletions(-)