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>
This commit is contained in:
Jeff Mahoney 2017-06-28 21:56:53 -06:00 committed by David Sterba
parent 23d1f73788
commit 1cbb1f454e
4 changed files with 91 additions and 89 deletions

View file

@ -5405,9 +5405,8 @@ unlock_exit:
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;