[PATCH 4.5 025/200] lib: lz4: fixed zram with lz4 on big endian machines

Greg Kroah-Hartman
2016-05-03T01:24:36Z

From: Rui Salvaterra <rsalvaterra@gmail.com>

commit 3e26a691fe3fe1e02a76e5bab0c143ace4b137b4 upstream.

Based on Sergey's test patch [1], this fixes zram with lz4 compression
on big endian cpus.

Note that the 64-bit preprocessor test is not a cleanup, it's part of
the fix, since those identifiers are bogus (for example, __ppc64__
isn't defined anywhere else in the kernel, which means we'd fall into
the 32-bit definitions on ppc64).

Tested on ppc64 with no regression on x86_64.

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

Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Rui Salvaterra <rsalvaterra@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
lib/lz4/lz4defs.h | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

--- 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
@@ -35,6 +34,10 @@ 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; \
@@ -51,10 +54,13 @@ 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

@@ -140,9 +146,6 @@ typedef struct _U64_S { u64 v; } U64_S;

#endif

-#define LZ4_READ_LITTLEENDIAN_16(d, s, p) \
- (d = s - get_unaligned_le16(p))
-
#define LZ4_WILDCOPY(s, d, e) \
do { \
LZ4_COPYPACKET(s, d); \