diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/struct-funcs.c | 43 |
1 files changed, 16 insertions, 27 deletions
diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c index e6d2bd019444..e357e0bab397 100644 --- a/fs/btrfs/struct-funcs.c +++ b/fs/btrfs/struct-funcs.c @@ -62,39 +62,28 @@ static bool check_setget_bounds(const struct extent_buffer *eb, u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \ const void *ptr, unsigned long off) \ { \ - 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; \ + const unsigned long member_offset = (unsigned long)ptr + off; \ + const unsigned long idx = member_offset >> PAGE_SHIFT; \ + const unsigned long oip = offset_in_page(member_offset); \ + const int size = sizeof(u##bits); \ + __le##bits leres; \ \ ASSERT(token); \ ASSERT(token->kaddr); \ ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \ - if (token->offset <= offset && \ - (token->offset + PAGE_SIZE >= offset + size)) { \ - kaddr = token->kaddr; \ - p = kaddr + part_offset - token->offset; \ - res = get_unaligned_le##bits(p + off); \ - return res; \ + if (token->offset <= member_offset && \ + member_offset + size <= token->offset + PAGE_SIZE) { \ + return get_unaligned_le##bits(token->kaddr + oip); \ } \ - err = map_private_extent_buffer(token->eb, offset, size, \ - &kaddr, &map_start, &map_len); \ - if (err) { \ - __le##bits leres; \ - \ - read_extent_buffer(token->eb, &leres, offset, size); \ - return le##bits##_to_cpu(leres); \ + if (oip + size <= PAGE_SIZE) { \ + token->kaddr = page_address(token->eb->pages[idx]); \ + token->offset = idx << PAGE_SHIFT; \ + return get_unaligned_le##bits(token->kaddr + oip); \ } \ - p = kaddr + part_offset - map_start; \ - res = get_unaligned_le##bits(p + off); \ - token->kaddr = kaddr; \ - token->offset = map_start; \ - return res; \ + token->kaddr = page_address(token->eb->pages[idx + 1]); \ + token->offset = (idx + 1) << PAGE_SHIFT; \ + read_extent_buffer(token->eb, &leres, member_offset, size); \ + return le##bits##_to_cpu(leres); \ } \ u##bits btrfs_get_##bits(const struct extent_buffer *eb, \ const void *ptr, unsigned long off) \ |