btrfs: struct-funcs, constify readers
We have reader helpers for most of the on-disk structures that use
an extent_buffer and pointer as offset into the buffer that are
read-only. We should mark them as const and, in turn, allow consumers
of these interfaces to mark the buffers const as well.
No impact on code, but serves as documentation that a buffer is intended
not to be modified.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0aff9b2..d6f761b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5405,9 +5405,8 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
return ret;
}
-void read_extent_buffer(struct extent_buffer *eb, void *dstv,
- unsigned long start,
- unsigned long len)
+void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
+ unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
@@ -5436,9 +5435,9 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
}
}
-int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
- unsigned long start,
- unsigned long len)
+int read_extent_buffer_to_user(const struct extent_buffer *eb,
+ void __user *dstv,
+ unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
@@ -5478,10 +5477,10 @@ int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
* return 1 if the item spans two pages.
* return -EINVAL otherwise.
*/
-int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
- unsigned long min_len, char **map,
- unsigned long *map_start,
- unsigned long *map_len)
+int map_private_extent_buffer(const struct extent_buffer *eb,
+ unsigned long start, unsigned long min_len,
+ char **map, unsigned long *map_start,
+ unsigned long *map_len)
{
size_t offset = start & (PAGE_SIZE - 1);
char *kaddr;
@@ -5515,9 +5514,8 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
return 0;
}
-int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
- unsigned long start,
- unsigned long len)
+int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
+ unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
