btrfs: use unaligned helpers for stack and header set/get helpers

In the definitions generated by BTRFS_SETGET_HEADER_FUNCS there's direct
pointer assignment but we should use the helpers for unaligned access
for clarity. It hasn't been a problem so far because of the natural
alignment.

Similarly for BTRFS_SETGET_STACK_FUNCS, that usually get a structure
from stack that has an aligned start but some members may not be aligned
due to packing. This as well hasn't caused problems so far.

Move the put/get_unaligned_le8 stubs to ctree.h so we can use them.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index cd644c75514283753dbd32d86026a2bac9e2daff..5cb8af6af25de57dae2c6ead7a33552eee7c7330 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1420,6 +1420,16 @@ static inline void btrfs_init_map_token(struct btrfs_map_token *token,
 #define cpu_to_le8(v) (v)
 #define __le8 u8
 
+static inline u8 get_unaligned_le8(const void *p)
+{
+       return *(u8 *)p;
+}
+
+static inline void put_unaligned_le8(u8 val, void *p)
+{
+       *(u8 *)p = val;
+}
+
 #define read_eb_member(eb, ptr, type, member, result) (\
        read_extent_buffer(eb, (char *)(result),                        \
                           ((unsigned long)(ptr)) +                     \
@@ -1478,27 +1488,25 @@ static inline void btrfs_set_token_##name(struct btrfs_map_token *token,\
 static inline u##bits btrfs_##name(const struct extent_buffer *eb)     \
 {                                                                      \
        const type *p = page_address(eb->pages[0]);                     \
-       u##bits res = le##bits##_to_cpu(p->member);                     \
-       return res;                                                     \
+       return get_unaligned_le##bits(&p->member);                      \
 }                                                                      \
 static inline void btrfs_set_##name(const struct extent_buffer *eb,    \
                                    u##bits val)                        \
 {                                                                      \
        type *p = page_address(eb->pages[0]);                           \
-       p->member = cpu_to_le##bits(val);                               \
+       put_unaligned_le##bits(val, &p->member);                        \
 }
 
 #define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)             \
 static inline u##bits btrfs_##name(const type *s)                      \
 {                                                                      \
-       return le##bits##_to_cpu(s->member);                            \
+       return get_unaligned_le##bits(&s->member);                      \
 }                                                                      \
 static inline void btrfs_set_##name(type *s, u##bits val)              \
 {                                                                      \
-       s->member = cpu_to_le##bits(val);                               \
+       put_unaligned_le##bits(val, &s->member);                        \
 }
 
-
 static inline u64 btrfs_device_total_bytes(const struct extent_buffer *eb,
                                           struct btrfs_dev_item *s)
 {

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index 079b059818e9a5557ef4203f3d953d8116e1343a..c46be27be700e7e95d2422c662141e249eea4240 100644 (file)
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -7,16 +7,6 @@
 
 #include "ctree.h"
 
-static inline u8 get_unaligned_le8(const void *p)
-{
-       return *(u8 *)p;
-}
-
-static inline void put_unaligned_le8(u8 val, void *p)
-{
-       *(u8 *)p = val;
-}
-
 static bool check_setget_bounds(const struct extent_buffer *eb,
                                const void *ptr, unsigned off, int size)
 {