From: Alexander Gordeev agordeev@linux.ibm.com Subject: lib: fix bitmap_parse() on 64-bit big endian archs

Commit 2d6261583be0 ("lib: rework bitmap_parse()") does not take into account order of halfwords on 64-bit big endian architectures. As result (at least) Receive Packet Steering, IRQ affinity masks and runtime kernel test "test_bitmap" get broken on s390.

[andriy.shevchenko@linux.intel.com: convert infinite while loop to a for loop] Link: http://lkml.kernel.org/r/20200609140535.87160-1-andriy.shevchenko@linux.inte... Link: http://lkml.kernel.org/r/1591634471-17647-1-git-send-email-agordeev@linux.ib... Fixes: 2d6261583be0 ("lib: rework bitmap_parse()") Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Cc: Yury Norov yury.norov@gmail.com Cc: Amritha Nambiar amritha.nambiar@intel.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Kees Cook keescook@chromium.org Cc: Matthew Wilcox willy@infradead.org Cc: Miklos Szeredi mszeredi@redhat.com Cc: Rasmus Villemoes linux@rasmusvillemoes.dk Cc: Steffen Klassert steffen.klassert@secunet.com Cc: "Tobin C . Harding" tobin@kernel.org Cc: Vineet Gupta vineet.gupta1@synopsys.com Cc: Will Deacon will.deacon@arm.com Cc: Willem de Bruijn willemb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

lib/bitmap.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/lib/bitmap.c~lib-fix-bitmap_parse-on-64-bit-big-endian-archs +++ a/lib/bitmap.c @@ -741,8 +741,9 @@ int bitmap_parse(const char *start, unsi int chunks = BITS_TO_U32(nmaskbits); u32 *bitmap = (u32 *)maskp; int unset_bit; + int chunk;

- while (1) { + for (chunk = 0; ; chunk++) { end = bitmap_find_region_reverse(start, end); if (start > end) break; @@ -750,7 +751,11 @@ int bitmap_parse(const char *start, unsi if (!chunks--) return -EOVERFLOW;

- end = bitmap_get_x32_reverse(start, end, bitmap++); +#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN) + end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]); +#else + end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]); +#endif if (IS_ERR(end)) return PTR_ERR(end); } _