btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios

These two functions are still using the old page based code, which is
not going to handle larger folios at all.

The migration itself is going to involve the following changes:

- PAGE_SIZE -> folio_size()
- PAGE_SHIFT -> folio_shift()
- get_eb_page_index() -> get_eb_folio_index()
- get_eb_offset_in_page() -> get_eb_offset_in_folio()

And since we're going to support larger folios, although above straight
conversion is good enough, this patch would add extra comments in the
involved functions to explain why the same single line code can now
cover 3 cases:

- folio_size == PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The common, non-subpage case with per-page folio.

- folio_size > PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The incoming larger folio, non-subpage case.

- folio_size == PAGE_SIZE, sectorsize < PAGE_SIZE, nodesize < PAGE_SIZE
  The existing subpage case, we won't larger folio anyway.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 44 insertions, 34 deletions

diff --git a/fs/btrfs/accessors.c b/fs/btrfs/accessors.c
index 8f7cbb7154d4..1925a0919ca6 100644
--- a/fs/btrfs/accessors.c
+++ b/fs/btrfs/accessors.c
@@ -60,28 +60,30 @@ 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_page_index(member_offset);	\
-	const unsigned long oip = get_eb_offset_in_page(token->eb,	\
-							member_offset);	\
+	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 = folio_size(token->eb->folios[0]);		\
+	const int unit_shift = folio_shift(token->eb->folios[0]);	\
 	const int size = sizeof(u##bits);				\
 	u8 lebytes[sizeof(u##bits)];					\
-	const int part = PAGE_SIZE - oip;				\
+	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 + PAGE_SIZE) {	\
-		return get_unaligned_le##bits(token->kaddr + oip);	\
+	    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 << PAGE_SHIFT;				\
-	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE ) \
-		return get_unaligned_le##bits(token->kaddr + oip);	\
+	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 + oip, part);			\
+	memcpy(lebytes, token->kaddr + oil, part);			\
 	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
-	token->offset = (idx + 1) << PAGE_SHIFT;			\
+	token->offset = (idx + 1) << unit_shift;			\
 	memcpy(lebytes + part, token->kaddr, size - part);		\
 	return get_unaligned_le##bits(lebytes);				\
 }									\
@@ -89,18 +91,20 @@ u##bits btrfs_get_##bits(const struct extent_buffer *eb,		\
 			 const void *ptr, unsigned long off)		\
 {									\
 	const unsigned long member_offset = (unsigned long)ptr + off;	\
-	const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
-	const unsigned long idx = get_eb_page_index(member_offset);	\
+	const unsigned long idx = get_eb_folio_index(eb, member_offset);\
+	const unsigned long oil = get_eb_offset_in_folio(eb,		\
+							 member_offset);\
+	const int unit_size = folio_size(eb->folios[0]);		\
 	char *kaddr = folio_address(eb->folios[idx]);			\
 	const int size = sizeof(u##bits);				\
-	const int part = PAGE_SIZE - oip;				\
+	const int part = unit_size - oil;				\
 	u8 lebytes[sizeof(u##bits)];					\
 									\
 	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
-	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE)	\
-		return get_unaligned_le##bits(kaddr + oip);		\
+	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size)	\
+		return get_unaligned_le##bits(kaddr + oil);		\
 									\
-	memcpy(lebytes, kaddr + oip, part);				\
+	memcpy(lebytes, kaddr + oil, part);				\
 	kaddr = folio_address(eb->folios[idx + 1]);			\
 	memcpy(lebytes + part, kaddr, size - part);			\
 	return get_unaligned_le##bits(lebytes);				\
@@ -110,52 +114,58 @@ void btrfs_set_token_##bits(struct btrfs_map_token *token,		\
 			    u##bits val)				\
 {									\
 	const unsigned long member_offset = (unsigned long)ptr + off;	\
-	const unsigned long idx = get_eb_page_index(member_offset);	\
-	const unsigned long oip = get_eb_offset_in_page(token->eb,	\
-							member_offset);	\
+	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 = folio_size(token->eb->folios[0]);		\
+	const int unit_shift = folio_shift(token->eb->folios[0]);	\
 	const int size = sizeof(u##bits);				\
 	u8 lebytes[sizeof(u##bits)];					\
-	const int part = PAGE_SIZE - oip;				\
+	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 + PAGE_SIZE) {	\
-		put_unaligned_le##bits(val, token->kaddr + oip);	\
+	    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 << PAGE_SHIFT;				\
-	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \
-		put_unaligned_le##bits(val, token->kaddr + oip);	\
+	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 + oip, lebytes, part);			\
+	memcpy(token->kaddr + oil, lebytes, part);			\
 	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
-	token->offset = (idx + 1) << PAGE_SHIFT;			\
+	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)			\
 {									\
 	const unsigned long member_offset = (unsigned long)ptr + off;	\
-	const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
-	const unsigned long idx = get_eb_page_index(member_offset);	\
+	const unsigned long idx = get_eb_folio_index(eb, member_offset);\
+	const unsigned long oil = get_eb_offset_in_folio(eb,		\
+							 member_offset);\
+	const int unit_size = folio_size(eb->folios[0]);		\
 	char *kaddr = folio_address(eb->folios[idx]);			\
 	const int size = sizeof(u##bits);				\
-	const int part = PAGE_SIZE - oip;				\
+	const int part = unit_size - oil;				\
 	u8 lebytes[sizeof(u##bits)];					\
 									\
 	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
-	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \
-		put_unaligned_le##bits(val, kaddr + oip);		\
+	if (INLINE_EXTENT_BUFFER_PAGES == 1 ||				\
+	    oil + size <= unit_size) {					\
+		put_unaligned_le##bits(val, kaddr + oil);		\
 		return;							\
 	}								\
 									\
 	put_unaligned_le##bits(val, lebytes);				\
-	memcpy(kaddr + oip, lebytes, part);				\
+	memcpy(kaddr + oil, lebytes, part);				\
 	kaddr = folio_address(eb->folios[idx + 1]);			\
 	memcpy(kaddr, lebytes + part, size - part);			\
 }