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Subject[PATCH 5.6 084/161] lib: fix bitmap_parse() on 64-bit big endian archs
Date
From: Alexander Gordeev <agordeev@linux.ibm.com>

commit 81c4f4d924d5d009b5ed785a3e22b18d0f7b831f upstream.

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.intel.com

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
Link: http://lkml.kernel.org/r/1591634471-17647-1-git-send-email-agordeev@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -740,8 +740,9 @@ 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;
@@ -749,7 +750,11 @@ 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);
}

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