btrfs: accessors: delete token versions of set/get helpers

Once upon a time there was a need to cache address of extent buffer
pages, as it was a costly operation (map_private_extent_buffer(),
cfed81a04eb555 ("Btrfs: add the ability to cache a pointer into the
eb")).  This was not even due to use of HIGHMEM, this had been removed
before that due to possible locking issues (a65917156e3459 ("Btrfs:
stop using highmem for extent_buffers")).

Over time the amount of work in the set/get helpers got reduced and
became quite straightforward bounds checking with an unaligned
read/write, commit db3756c879773c ("btrfs: remove unused
map_private_extent_buffer").

The actual caching of the page_address()/folio_address() in the token
was more work for very little gain. This depended on subsequent access
into the same page/folio, otherwise the cached pointer had to be
updated.

For metadata-heavy operations this showed up in the 'perf top' profile
where the btrfs_get_token_32() calls were at the top, on my testing
machine consuming about 2-3%. The other generic 32/64 bit helpers also
appeared in the profile with similar fraction.

After removing use of the token helpers we can remove them completely,
this leads to reduction of btrfs.ko by 6.7KiB on release config.

   text    data     bss     dec     hex filename
1463289  115665   16088 1595042  1856a2 pre/btrfs.ko
1456601  115665   16088 1588354  183c82 post/btrfs.ko

DELTA: -6688

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 0 insertions, 78 deletions

diff --git a/fs/btrfs/accessors.c b/fs/btrfs/accessors.c
index e3716516ca38..5cfb0801700e 100644
--- a/fs/btrfs/accessors.c
+++ b/fs/btrfs/accessors.c
@@ -25,13 +25,6 @@ static bool check_setget_bounds(const struct extent_buffer *eb,
 	return true;
 }
 
-void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb)
-{
-	token->eb = eb;
-	token->kaddr = folio_address(eb->folios[0]);
-	token->offset = 0;
-}
-
 /*
  * Macro templates that define helpers to read/write extent buffer data of a
  * given size, that are also used via ctree.h for access to item members by
@@ -41,11 +34,6 @@ void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *e
  * - btrfs_set_8 (for 8/16/32/64)
  * - btrfs_get_8 (for 8/16/32/64)
  *
- * Generic helpers with a token (cached address of the most recently accessed
- * page):
- * - btrfs_set_token_8 (for 8/16/32/64)
- * - btrfs_get_token_8 (for 8/16/32/64)
- *
  * The set/get functions handle data spanning two pages transparently, in case
  * metadata block size is larger than page.  Every pointer to metadata items is
  * an offset into the extent buffer page array, cast to a specific type.  This
@@ -57,37 +45,6 @@ void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *e
  */
 
 #define DEFINE_BTRFS_SETGET_BITS(bits)					\
-u##bits btrfs_get_token_##bits(struct btrfs_map_token *token,		\
-			       const void *ptr, unsigned long off)	\
-{									\
-	const unsigned long member_offset = (unsigned long)ptr + off;	\
-	const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \
-	const unsigned long oil = get_eb_offset_in_folio(token->eb,	\
-							 member_offset);\
-	const int unit_size = token->eb->folio_size;			\
-	const int unit_shift = token->eb->folio_shift;			\
-	const int size = sizeof(u##bits);				\
-	u8 lebytes[sizeof(u##bits)];					\
-	const int part = unit_size - oil;				\
-									\
-	ASSERT(token);							\
-	ASSERT(token->kaddr);						\
-	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
-	if (token->offset <= member_offset &&				\
-	    member_offset + size <= token->offset + unit_size) {	\
-		return get_unaligned_le##bits(token->kaddr + oil);	\
-	}								\
-	token->kaddr = folio_address(token->eb->folios[idx]);		\
-	token->offset = idx << unit_shift;				\
-	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \
-		return get_unaligned_le##bits(token->kaddr + oil);	\
-									\
-	memcpy(lebytes, token->kaddr + oil, part);			\
-	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
-	token->offset = (idx + 1) << unit_shift;			\
-	memcpy(lebytes + part, token->kaddr, size - part);		\
-	return get_unaligned_le##bits(lebytes);				\
-}									\
 u##bits btrfs_get_##bits(const struct extent_buffer *eb,		\
 			 const void *ptr, unsigned long off)		\
 {									\
@@ -110,41 +67,6 @@ u##bits btrfs_get_##bits(const struct extent_buffer *eb,		\
 	memcpy(lebytes + part, kaddr, size - part);			\
 	return get_unaligned_le##bits(lebytes);				\
 }									\
-void btrfs_set_token_##bits(struct btrfs_map_token *token,		\
-			    const void *ptr, unsigned long off,		\
-			    u##bits val)				\
-{									\
-	const unsigned long member_offset = (unsigned long)ptr + off;	\
-	const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \
-	const unsigned long oil = get_eb_offset_in_folio(token->eb,	\
-							 member_offset);\
-	const int unit_size = token->eb->folio_size;			\
-	const int unit_shift = token->eb->folio_shift;			\
-	const int size = sizeof(u##bits);				\
-	u8 lebytes[sizeof(u##bits)];					\
-	const int part = unit_size - oil;				\
-									\
-	ASSERT(token);							\
-	ASSERT(token->kaddr);						\
-	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
-	if (token->offset <= member_offset &&				\
-	    member_offset + size <= token->offset + unit_size) {	\
-		put_unaligned_le##bits(val, token->kaddr + oil);	\
-		return;							\
-	}								\
-	token->kaddr = folio_address(token->eb->folios[idx]);		\
-	token->offset = idx << unit_shift;				\
-	if (INLINE_EXTENT_BUFFER_PAGES == 1 ||				\
-	    oil + size <= unit_size) {					\
-		put_unaligned_le##bits(val, token->kaddr + oil);	\
-		return;							\
-	}								\
-	put_unaligned_le##bits(val, lebytes);				\
-	memcpy(token->kaddr + oil, lebytes, part);			\
-	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
-	token->offset = (idx + 1) << unit_shift;			\
-	memcpy(token->kaddr, lebytes + part, size - part);		\
-}									\
 void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr,	\
 		      unsigned long off, u##bits val)			\
 {									\