[PATCH 0/4] bitmap: fix conversion from/to fix-sized arrays

Yury Norov
2022-04-20T22:25:47Z

In the kernel codebase we have functions that call bitmap_copy()
to convert bitmaps to and from fix-sized 32 or 64-bit arrays. It
works well for LE architectures when size of long is equal to the
size of fixed type.

If the system is BE and/or size of long is not equal to the size of
fixed type of the array, bitmap_copy() may produce wrong result either
because of endianness issue, or because of out-of-bound access.

To address this problem we already have bitmap_{from,to}_arr32().
In recent discussion it was spotted that we also need 64-bit
analogue of it:
https://lore.kernel.org/all/YiCWNdWd+AsLbDkp@smile.fi.intel.com/T/#m754da92acb0003e12b99293d07ddcd46dbe04ada

This series takes care of it.

Yury Norov (4):
lib/bitmap: extend comment for bitmap_(from,to)_arr32()
lib: add bitmap_{from,to}_arr64
KVM: s390: replace bitmap_copy with bitmap_{from,to}_arr64 where
appropriate
drm/amd/pm: use bitmap_{from,to}_arr32 where appropriate

arch/s390/kvm/kvm-s390.c | 10 ++--
.../gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c | 2 +-
.../gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c | 2 +-
include/linux/bitmap.h | 31 +++++++++---
lib/bitmap.c | 47 +++++++++++++++++++
5 files changed, 77 insertions(+), 15 deletions(-)

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2.32.0