Based on Sergey's test patch [1], this fixes zram with lz4 compression on big 
endian cpus. Tested on ppc64 with no regression on x86_64.

[1] http://marc.info/?l=linux-kernel&m=145994470805853&w=4

Cc: [email protected]
Signed-off-by: Rui Salvaterra <[email protected]>
---
 lib/lz4/lz4defs.h | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/lib/lz4/lz4defs.h b/lib/lz4/lz4defs.h
index abcecdc..a98c08c 100644
--- a/lib/lz4/lz4defs.h
+++ b/lib/lz4/lz4defs.h
@@ -11,8 +11,7 @@
 /*
  * Detects 64 bits mode
  */
-#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) \
-       || defined(__ppc64__) || defined(__LP64__))
+#if defined(CONFIG_64BIT)
 #define LZ4_ARCH64 1
 #else
 #define LZ4_ARCH64 0
@@ -25,9 +24,7 @@
 typedef struct _U16_S { u16 v; } U16_S;
 typedef struct _U32_S { u32 v; } U32_S;
 typedef struct _U64_S { u64 v; } U64_S;
-#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)            \
-       || defined(CONFIG_ARM) && __LINUX_ARM_ARCH__ >= 6       \
-       && defined(ARM_EFFICIENT_UNALIGNED_ACCESS)
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 
 #define A16(x) (((U16_S *)(x))->v)
 #define A32(x) (((U32_S *)(x))->v)
@@ -35,6 +32,10 @@ typedef struct _U64_S { u64 v; } U64_S;
 
 #define PUT4(s, d) (A32(d) = A32(s))
 #define PUT8(s, d) (A64(d) = A64(s))
+
+#define LZ4_READ_LITTLEENDIAN_16(d, s, p)      \
+       (d = s - A16(p))
+
 #define LZ4_WRITE_LITTLEENDIAN_16(p, v)        \
        do {    \
                A16(p) = v; \
@@ -51,12 +52,15 @@ typedef struct _U64_S { u64 v; } U64_S;
 #define PUT8(s, d) \
        put_unaligned(get_unaligned((const u64 *) s), (u64 *) d)
 
-#define LZ4_WRITE_LITTLEENDIAN_16(p, v)        \
-       do {    \
-               put_unaligned(v, (u16 *)(p)); \
-               p += 2; \
+#define LZ4_READ_LITTLEENDIAN_16(d, s, p)      \
+       (d = s - get_unaligned_le16(p))
+
+#define LZ4_WRITE_LITTLEENDIAN_16(p, v)                        \
+       do {                                            \
+               put_unaligned_le16(v, (u16 *)(p));      \
+               p += 2;                                 \
        } while (0)
-#endif
+#endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */
 
 #define COPYLENGTH 8
 #define ML_BITS  4
@@ -138,10 +142,7 @@ typedef struct _U64_S { u64 v; } U64_S;
 #define LZ4_NBCOMMONBYTES(val) (__builtin_ctz(val) >> 3)
 #endif
 
-#endif
-
-#define LZ4_READ_LITTLEENDIAN_16(d, s, p) \
-       (d = s - get_unaligned_le16(p))
+#endif /* LZ4_ARCH64 */
 
 #define LZ4_WILDCOPY(s, d, e)          \
        do {                            \
-- 
2.7.4

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