*/
#include <linux/highmem.h>
+
+/* this is some deeply nasty code. ctree.h has a different
+ * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef
+ *
+ * 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.
+ *
+ * These setget functions do all the extent_buffer related mapping
+ * required to efficiently read and write specific fields in the extent
+ * buffers. Every pointer to metadata items in btrfs is really just
+ * 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.
+ */
+
#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); \
u##bits btrfs_##name(struct extent_buffer *eb, \
type *s) \
{ \
int unmap_on_exit = (eb->map_token == NULL); \
unsigned long map_start; \
unsigned long map_len; \
- __le##bits res; \
+ u##bits res; \
err = map_extent_buffer(eb, offset, \
- sizeof(((type *)0)->member), \
+ sizeof(((type *)0)->member), \
&map_token, &kaddr, \
&map_start, &map_len, KM_USER1); \
if (err) { \
- read_eb_member(eb, s, type, member, &res); \
- return le##bits##_to_cpu(res); \
+ __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); \
unsigned long map_start; \
unsigned long map_len; \
err = map_extent_buffer(eb, offset, \
- sizeof(((type *)0)->member), \
+ sizeof(((type *)0)->member), \
&map_token, &kaddr, \
&map_start, &map_len, KM_USER1); \
if (err) { \
- val = cpu_to_le##bits(val); \
- write_eb_member(eb, s, type, member, &val); \
+ __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); \