*/
#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) \
{ \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
type *p; \
- /* ugly, but we want the fast path here */ \
- if (eb->map_token && offset >= eb->map_start && \
- offset + sizeof(((type *)0)->member) <= eb->map_start + \
- eb->map_len) { \
- p = (type *)(eb->kaddr + part_offset - eb->map_start); \
- return le##bits##_to_cpu(p->member); \
- } \
- { \
- int err; \
- char *map_token; \
- char *kaddr; \
- int unmap_on_exit = (eb->map_token == NULL); \
- unsigned long map_start; \
- unsigned long map_len; \
- __le##bits res; \
- err = map_extent_buffer(eb, offset, \
- 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); \
- } \
- p = (type *)(kaddr + part_offset - map_start); \
- res = le##bits##_to_cpu(p->member); \
- if (unmap_on_exit) \
- unmap_extent_buffer(eb, map_token, KM_USER1); \
- return res; \
- } \
+ int err; \
+ char *kaddr; \
+ unsigned long map_start; \
+ unsigned long map_len; \
+ u##bits res; \
+ err = map_private_extent_buffer(eb, offset, \
+ sizeof(((type *)0)->member), \
+ &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); \
+ return res; \
} \
void btrfs_set_##name(struct extent_buffer *eb, \
type *s, u##bits val) \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
type *p; \
- /* ugly, but we want the fast path here */ \
- if (eb->map_token && offset >= eb->map_start && \
- offset + sizeof(((type *)0)->member) <= eb->map_start + \
- eb->map_len) { \
- p = (type *)(eb->kaddr + part_offset - eb->map_start); \
- p->member = cpu_to_le##bits(val); \
- return; \
- } \
- { \
- int err; \
- char *map_token; \
- char *kaddr; \
- int unmap_on_exit = (eb->map_token == NULL); \
- unsigned long map_start; \
- unsigned long map_len; \
- err = map_extent_buffer(eb, offset, \
- 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); \
- return; \
- } \
- p = (type *)(kaddr + part_offset - map_start); \
- p->member = cpu_to_le##bits(val); \
- if (unmap_on_exit) \
- unmap_extent_buffer(eb, map_token, KM_USER1); \
- } \
+ int err; \
+ char *kaddr; \
+ unsigned long map_start; \
+ unsigned long map_len; \
+ err = map_private_extent_buffer(eb, offset, \
+ sizeof(((type *)0)->member), \
+ &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); \
}
#include "ctree.h"
struct btrfs_disk_key *disk_key, int nr)
{
unsigned long ptr = btrfs_node_key_ptr_offset(nr);
- if (eb->map_token && ptr >= eb->map_start &&
- ptr + sizeof(*disk_key) <= eb->map_start + eb->map_len) {
- memcpy(disk_key, eb->kaddr + ptr - eb->map_start,
- sizeof(*disk_key));
- return;
- } else if (eb->map_token) {
- unmap_extent_buffer(eb, eb->map_token, KM_USER1);
- eb->map_token = NULL;
- }
read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
struct btrfs_key_ptr, key, disk_key);
}
git.openpandora.org / pandora-kernel.git / blobdiff