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.

Fixes: 2d6261583be0 ("lib: rework bitmap_parse()")
Cc: [email protected]
Cc: Andrew Morton <[email protected]>
Cc: Yury Norov <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Amritha Nambiar <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Steffen Klassert <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Willem de Bruijn <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>
---
 lib/bitmap.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 89260aa342d6..80d26b183248 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -739,6 +739,7 @@ int bitmap_parse(const char *start, unsigned int buflen,
        const char *end = strnchrnul(start, buflen, '\n') - 1;
        int chunks = BITS_TO_U32(nmaskbits);
        u32 *bitmap = (u32 *)maskp;
+       int chunk = 0;
        int unset_bit;
 
        while (1) {
@@ -749,9 +750,14 @@ int bitmap_parse(const char *start, unsigned int buflen,
                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);
+               chunk++;
        }
 
        unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
-- 
2.23.0

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