Btrfs: extent_map optimizations to cut down on CPU usage

[deliverable/linux.git] / fs / btrfs / ctree.h

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 18994c53106cf1125c7a74e7d12ee713a008a61a..a942a242722841f931390d7a1bfe3d3c6db89169 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -19,6 +19,8 @@
 #ifndef __BTRFS__
 #define __BTRFS__
 
+#include <linux/mm.h>
+#include <linux/highmem.h>
 #include <linux/fs.h>
 #include <linux/workqueue.h>
 #include <linux/completion.h>
@@ -499,70 +501,22 @@ static inline void btrfs_set_##name(struct extent_buffer *eb,             \
 #define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)            \
 static inline u##bits btrfs_##name(struct extent_buffer *eb)           \
 {                                                                      \
-       int err;                                                        \
-       char *map_token;                                                \
-       char *kaddr;                                                    \
-       unsigned long map_start;                                        \
-       unsigned long map_len;                                          \
+       char *kaddr = kmap_atomic(eb->first_page, KM_USER0);            \
        unsigned long offset = offsetof(type, member);                  \
-       int unmap_on_exit = (eb->map_token == NULL);                    \
-       if (eb->map_token && offset >= eb->map_start &&                 \
-           offset + sizeof(((type *)0)->member) <= eb->map_start +     \
-           eb->map_len) {                                              \
-           kaddr = eb->kaddr;                                          \
-           map_start = eb->map_start;                                  \
-           err = 0;                                                    \
-       } else {                                                        \
-               err = map_extent_buffer(eb, offset,                     \
-                               sizeof(((type *)0)->member),            \
-                               &map_token, &kaddr,                     \
-                               &map_start, &map_len, KM_USER1);        \
-       }                                                               \
-       if (!err) {                                                     \
-               __le##bits *tmp = (__le##bits *)(kaddr + offset -       \
-                                              map_start);              \
-               u##bits res = le##bits##_to_cpu(*tmp);                  \
-               if (unmap_on_exit)                                      \
-                       unmap_extent_buffer(eb, map_token, KM_USER1);   \
-               return res;                                             \
-       } else {                                                        \
-               __le##bits res;                                         \
-               read_eb_member(eb, NULL, type, member, &res);           \
-               return le##bits##_to_cpu(res);                          \
-       }                                                               \
+       u##bits res;                                                    \
+       __le##bits *tmp = (__le##bits *)(kaddr + offset);               \
+       res = le##bits##_to_cpu(*tmp);                                  \
+       kunmap_atomic(kaddr, KM_USER0);                                 \
+       return res;                                                     \
 }                                                                      \
 static inline void btrfs_set_##name(struct extent_buffer *eb,          \
                                    u##bits val)                        \
 {                                                                      \
-       int err;                                                        \
-       char *map_token;                                                \
-       char *kaddr;                                                    \
-       unsigned long map_start;                                        \
-       unsigned long map_len;                                          \
+       char *kaddr = kmap_atomic(eb->first_page, KM_USER0);            \
        unsigned long offset = offsetof(type, member);                  \
-       int unmap_on_exit = (eb->map_token == NULL);                    \
-       if (eb->map_token && offset >= eb->map_start &&                 \
-           offset + sizeof(((type *)0)->member) <= eb->map_start +     \
-           eb->map_len) {                                              \
-           kaddr = eb->kaddr;                                          \
-           map_start = eb->map_start;                                  \
-           err = 0;                                                    \
-       } else {                                                        \
-               err = map_extent_buffer(eb, offset,                     \
-                               sizeof(((type *)0)->member),            \
-                               &map_token, &kaddr,                     \
-                               &map_start, &map_len, KM_USER1);        \
-       }                                                               \
-       if (!err) {                                                     \
-               __le##bits *tmp = (__le##bits *)(kaddr + offset -       \
-                                              map_start);              \
-               *tmp = cpu_to_le##bits(val);                            \
-               if (unmap_on_exit)                                      \
-                       unmap_extent_buffer(eb, map_token, KM_USER1);   \
-       } else {                                                        \
-               val = cpu_to_le##bits(val);                             \
-               write_eb_member(eb, NULL, type, member, &val);          \
-       }                                                               \
+       __le##bits *tmp = (__le##bits *)(kaddr + offset);               \
+       *tmp = cpu_to_le##bits(val);                                    \
+       kunmap_atomic(kaddr, KM_USER0);                                 \
 }
 
 #define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)             \
@@ -659,13 +613,13 @@ static inline void btrfs_set_node_blockptr(struct extent_buffer *eb,
        btrfs_set_key_blockptr(eb, (struct btrfs_key_ptr *)ptr, val);
 }
 
-static unsigned long btrfs_node_key_ptr_offset(int nr)
+static inline unsigned long btrfs_node_key_ptr_offset(int nr)
 {
        return offsetof(struct btrfs_node, ptrs) +
                sizeof(struct btrfs_key_ptr) * nr;
 }
 
-static void btrfs_node_key(struct extent_buffer *eb,
+static inline void btrfs_node_key(struct extent_buffer *eb,
                           struct btrfs_disk_key *disk_key, int nr)
 {
        unsigned long ptr;