[PATCH 1/4] btrfs-progs: constify extent buffer reader

[Qu Wenruo <wqu@suse.com>]

Add const prefix for the following parameters:
- @eb of memcmp_extent_buffer()
- @eb of read_extent_buffer()

This backports kernel commit 1cbb1f454e53 ("btrfs: struct-funcs,
constify readers") to btrfs-progs.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 extent_io.c | 4 ++--
 extent_io.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/extent_io.c b/extent_io.c
index c57f62829bf7..a9ceff5111fb 100644
--- a/extent_io.c
+++ b/extent_io.c
@@ -963,13 +963,13 @@ int clear_extent_buffer_dirty(struct extent_buffer *eb)
 	return 0;
 }
 
-int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
+int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
 			 unsigned long start, unsigned long len)
 {
 	return memcmp(eb->data + start, ptrv, len);
 }
 
-void read_extent_buffer(struct extent_buffer *eb, void *dst,
+void read_extent_buffer(const struct extent_buffer *eb, void *dst,
 			unsigned long start, unsigned long len)
 {
 	memcpy(dst, eb->data + start, len);
diff --git a/extent_io.h b/extent_io.h
index 9587528bbefb..874cbca1d436 100644
--- a/extent_io.h
+++ b/extent_io.h
@@ -154,9 +154,9 @@ void free_extent_buffer_nocache(struct extent_buffer *eb);
 int read_extent_from_disk(struct extent_buffer *eb,
 			  unsigned long offset, unsigned long len);
 int write_extent_to_disk(struct extent_buffer *eb);
-int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
+int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
 			 unsigned long start, unsigned long len);
-void read_extent_buffer(struct extent_buffer *eb, void *dst,
+void read_extent_buffer(const struct extent_buffer *eb, void *dst,
 			unsigned long start, unsigned long len);
 void write_extent_buffer(struct extent_buffer *eb, const void *src,
 			 unsigned long start, unsigned long len);
-- 
2.22.0