Both __block_write_full_folio() and block_read_full_folio() assumed
that block size <= PAGE_SIZE. Replace the shift with a divide, which
is probably cheaper than first calculating the shift. That lets us
remove block_size_bits() as these were the last callers.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/buffer.c | 27 ++++++---------------------
1 file changed, 6 insertions(+), 21 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index ef444ab53a9b..4eb44ccdc6be 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1742,19 +1742,6 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
}
EXPORT_SYMBOL(clean_bdev_aliases);
-/*
- * Size is a power-of-two in the range 512..PAGE_SIZE,
- * and the case we care about most is PAGE_SIZE.
- *
- * So this *could* possibly be written with those
- * constraints in mind (relevant mostly if some
- * architecture has a slow bit-scan instruction)
- */
-static inline int block_size_bits(unsigned int blocksize)
-{
- return ilog2(blocksize);
-}
-
static struct buffer_head *folio_create_buffers(struct folio *folio,
struct inode *inode,
unsigned int b_state)
@@ -1807,7 +1794,7 @@ int __block_write_full_folio(struct inode *inode, struct folio *folio,
sector_t block;
sector_t last_block;
struct buffer_head *bh, *head;
- unsigned int blocksize, bbits;
+ size_t blocksize;
int nr_underway = 0;
blk_opf_t write_flags = wbc_to_write_flags(wbc);
@@ -1826,10 +1813,9 @@ int __block_write_full_folio(struct inode *inode, struct folio *folio,
bh = head;
blocksize = bh->b_size;
- bbits = block_size_bits(blocksize);
- block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
- last_block = (i_size_read(inode) - 1) >> bbits;
+ block = div_u64(folio_pos(folio), blocksize);
+ last_block = div_u64(i_size_read(inode) - 1, blocksize);
/*
* Get all the dirty buffers mapped to disk addresses and
@@ -2355,7 +2341,7 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block)
struct inode *inode = folio->mapping->host;
sector_t iblock, lblock;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
- unsigned int blocksize, bbits;
+ size_t blocksize;
int nr, i;
int fully_mapped = 1;
bool page_error = false;
@@ -2369,10 +2355,9 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block)
head = folio_create_buffers(folio, inode, 0);
blocksize = head->b_size;
- bbits = block_size_bits(blocksize);
- iblock = (sector_t)folio->index << (PAGE_SHIFT - bbits);
- lblock = (limit+blocksize-1) >> bbits;
+ iblock = div_u64(folio_pos(folio), blocksize);
+ lblock = div_u64(limit + blocksize - 1, blocksize);
bh = head;
nr = 0;
i = 0;
--
2.42.0
