From 7b668965f0cf3fb8632c505a7a011189ee1a5a8e Mon Sep 17 00:00:00 2001 From: Ben Peddell Date: Sun, 27 Jan 2013 15:45:43 +1000 Subject: btrfs-progs: fix unaligned accesses v2 gcc optimizes out the memcpy calls at -O2 and -Os. Replacing memcpy with memmove does't work - gcc treats memmove the same way it treats memcpy. This patch brings in {get|put}_unaligned_le{16|32|64} (using the packed struct method), and uses them in the failing get/set calls. On architectures where unaligned accesses are cheap, these unaligned macros should be optimized out by the compiler. Signed-off-by: Ben Peddell --- kerncompat.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kerncompat.h') diff --git a/kerncompat.h b/kerncompat.h index d60f722..a38a9b0 100644 --- a/kerncompat.h +++ b/kerncompat.h @@ -267,6 +267,19 @@ typedef u64 __bitwise __be64; #define cpu_to_le16(x) ((__force __le16)(u16)(x)) #define le16_to_cpu(x) ((__force u16)(__le16)(x)) #endif + +struct __una_u16 { u16 x; } __attribute__((__packed__)); +struct __una_u32 { u32 x; } __attribute__((__packed__)); +struct __una_u64 { u64 x; } __attribute__((__packed__)); + +#define get_unaligned_le8(p) (*((u8 *)(p))) +#define put_unaligned_le8(val,p) ((*((u8 *)(p))) = (val)) +#define get_unaligned_le16(p) le16_to_cpu(((const struct __una_u16 *)(p))->x) +#define put_unaligned_le16(val,p) (((struct __una_u16 *)(p))->x = cpu_to_le16(val)) +#define get_unaligned_le32(p) le32_to_cpu(((const struct __una_u32 *)(p))->x) +#define put_unaligned_le32(val,p) (((struct __una_u32 *)(p))->x = cpu_to_le32(val)) +#define get_unaligned_le64(p) le64_to_cpu(((const struct __una_u64 *)(p))->x) +#define put_unaligned_le64(val,p) (((struct __una_u64 *)(p))->x = cpu_to_le64(val)) #endif #ifndef noinline -- cgit v1.2.1