diff options
Diffstat (limited to 'fs/btrfs/struct-funcs.c')
| -rw-r--r-- | fs/btrfs/struct-funcs.c | 196 |
1 files changed, 99 insertions, 97 deletions
diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c index c6ffa581241..b976597b072 100644 --- a/fs/btrfs/struct-funcs.c +++ b/fs/btrfs/struct-funcs.c @@ -17,15 +17,27 @@ */ #include <linux/highmem.h> +#include <asm/unaligned.h> -/* this is some deeply nasty code. ctree.h has a different - * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef +#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; +} + +/* + * this is some deeply nasty code. * * The end result is that anyone who #includes ctree.h gets a - * declaration for the btrfs_set_foo functions and btrfs_foo functions - * - * This file declares the macros and then #includes ctree.h, which results - * in cpp creating the function here based on the template below. + * declaration for the btrfs_set_foo functions and btrfs_foo functions, + * which are wappers of btrfs_set_token_#bits functions and + * btrfs_get_token_#bits functions, which are defined in this file. * * These setget functions do all the extent_buffer related mapping * required to efficiently read and write specific fields in the extent @@ -33,103 +45,93 @@ * an unsigned long offset into the extent buffer which has been * cast to a specific type. This gives us all the gcc type checking. * - * The extent buffer api is used to do all the kmapping and page - * spanning work required to get extent buffers in highmem and have - * a metadata blocksize different from the page size. - * - * The macro starts with a simple function prototype declaration so that - * sparse won't complain about it being static. + * The extent buffer api is used to do the page spanning work required to + * have a metadata blocksize different from the page size. */ -#define BTRFS_SETGET_FUNCS(name, type, member, bits) \ -u##bits btrfs_##name(struct extent_buffer *eb, type *s); \ -void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val); \ -void btrfs_set_token_##name(struct extent_buffer *eb, type *s, u##bits val, struct btrfs_map_token *token); \ -u##bits btrfs_token_##name(struct extent_buffer *eb, \ - type *s, struct btrfs_map_token *token) \ +#define DEFINE_BTRFS_SETGET_BITS(bits) \ +u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr, \ + unsigned long off, \ + struct btrfs_map_token *token) \ { \ - unsigned long part_offset = (unsigned long)s; \ - unsigned long offset = part_offset + offsetof(type, member); \ - type *p; \ - int err; \ - char *kaddr; \ - unsigned long map_start; \ - unsigned long map_len; \ - unsigned long mem_len = sizeof(((type *)0)->member); \ - u##bits res; \ - if (token && token->kaddr && token->offset <= offset && \ - token->eb == eb && \ - (token->offset + PAGE_CACHE_SIZE >= offset + mem_len)) { \ - kaddr = token->kaddr; \ - p = (type *)(kaddr + part_offset - token->offset); \ - res = le##bits##_to_cpu(p->member); \ - return res; \ - } \ - err = map_private_extent_buffer(eb, offset, \ - mem_len, \ - &kaddr, &map_start, &map_len); \ - if (err) { \ - __le##bits leres; \ - read_eb_member(eb, s, type, member, &leres); \ - return le##bits##_to_cpu(leres); \ - } \ - p = (type *)(kaddr + part_offset - map_start); \ - res = le##bits##_to_cpu(p->member); \ - if (token) { \ - token->kaddr = kaddr; \ - token->offset = map_start; \ - token->eb = eb; \ - } \ - return res; \ + unsigned long part_offset = (unsigned long)ptr; \ + unsigned long offset = part_offset + off; \ + void *p; \ + int err; \ + char *kaddr; \ + unsigned long map_start; \ + unsigned long map_len; \ + int size = sizeof(u##bits); \ + u##bits res; \ + \ + if (token && token->kaddr && token->offset <= offset && \ + token->eb == eb && \ + (token->offset + PAGE_CACHE_SIZE >= offset + size)) { \ + kaddr = token->kaddr; \ + p = kaddr + part_offset - token->offset; \ + res = get_unaligned_le##bits(p + off); \ + return res; \ + } \ + err = map_private_extent_buffer(eb, offset, size, \ + &kaddr, &map_start, &map_len); \ + if (err) { \ + __le##bits leres; \ + \ + read_extent_buffer(eb, &leres, offset, size); \ + return le##bits##_to_cpu(leres); \ + } \ + p = kaddr + part_offset - map_start; \ + res = get_unaligned_le##bits(p + off); \ + if (token) { \ + token->kaddr = kaddr; \ + token->offset = map_start; \ + token->eb = eb; \ + } \ + return res; \ } \ -void btrfs_set_token_##name(struct extent_buffer *eb, \ - type *s, u##bits val, struct btrfs_map_token *token) \ +void btrfs_set_token_##bits(struct extent_buffer *eb, \ + void *ptr, unsigned long off, u##bits val, \ + struct btrfs_map_token *token) \ { \ - unsigned long part_offset = (unsigned long)s; \ - unsigned long offset = part_offset + offsetof(type, member); \ - type *p; \ - int err; \ - char *kaddr; \ - unsigned long map_start; \ - unsigned long map_len; \ - unsigned long mem_len = sizeof(((type *)0)->member); \ - if (token && token->kaddr && token->offset <= offset && \ - token->eb == eb && \ - (token->offset + PAGE_CACHE_SIZE >= offset + mem_len)) { \ - kaddr = token->kaddr; \ - p = (type *)(kaddr + part_offset - token->offset); \ - p->member = cpu_to_le##bits(val); \ - return; \ - } \ - err = map_private_extent_buffer(eb, offset, \ - mem_len, \ - &kaddr, &map_start, &map_len); \ - if (err) { \ - __le##bits val2; \ - val2 = cpu_to_le##bits(val); \ - write_eb_member(eb, s, type, member, &val2); \ - return; \ - } \ - p = (type *)(kaddr + part_offset - map_start); \ - p->member = cpu_to_le##bits(val); \ - if (token) { \ - token->kaddr = kaddr; \ - token->offset = map_start; \ - token->eb = eb; \ - } \ -} \ -void btrfs_set_##name(struct extent_buffer *eb, \ - type *s, u##bits val) \ -{ \ - btrfs_set_token_##name(eb, s, val, NULL); \ -} \ -u##bits btrfs_##name(struct extent_buffer *eb, \ - type *s) \ -{ \ - return btrfs_token_##name(eb, s, NULL); \ -} \ + unsigned long part_offset = (unsigned long)ptr; \ + unsigned long offset = part_offset + off; \ + void *p; \ + int err; \ + char *kaddr; \ + unsigned long map_start; \ + unsigned long map_len; \ + int size = sizeof(u##bits); \ + \ + if (token && token->kaddr && token->offset <= offset && \ + token->eb == eb && \ + (token->offset + PAGE_CACHE_SIZE >= offset + size)) { \ + kaddr = token->kaddr; \ + p = kaddr + part_offset - token->offset; \ + put_unaligned_le##bits(val, p + off); \ + return; \ + } \ + err = map_private_extent_buffer(eb, offset, size, \ + &kaddr, &map_start, &map_len); \ + if (err) { \ + __le##bits val2; \ + \ + val2 = cpu_to_le##bits(val); \ + write_extent_buffer(eb, &val2, offset, size); \ + return; \ + } \ + p = kaddr + part_offset - map_start; \ + put_unaligned_le##bits(val, p + off); \ + if (token) { \ + token->kaddr = kaddr; \ + token->offset = map_start; \ + token->eb = eb; \ + } \ +} -#include "ctree.h" +DEFINE_BTRFS_SETGET_BITS(8) +DEFINE_BTRFS_SETGET_BITS(16) +DEFINE_BTRFS_SETGET_BITS(32) +DEFINE_BTRFS_SETGET_BITS(64) void btrfs_node_key(struct extent_buffer *eb, struct btrfs_disk_key *disk_key, int nr) |