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iomap: use find_next_bit() for uptodate bitmap scanning

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Use find_next_bit()/find_next_zero_bit() for iomap uptodate bitmap
scanning. This uses __ffs() internally and is more efficient for
finding the next uptodate or non-uptodate bit than iterating through the
the bitmap range testing every bit.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://patch.msgid.link/20251111193658.3495942-10-joannelkoong@gmail.com
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Joanne Koong 2025-11-11 11:36:58 -08:00 committed by Christian Brauner
parent fed9c62d28
commit b56c1c54f2
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 32 additions and 20 deletions
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52
fs/iomap/buffered-io.c
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@ -38,10 +38,28 @@ static inline bool ifs_is_fully_uptodate(struct folio *folio,
return bitmap_full(ifs->state, i_blocks_per_folio(inode, folio));
}
static inline bool ifs_block_is_uptodate(struct iomap_folio_state *ifs,
unsigned int block)
/*
* Find the next uptodate block in the folio. end_blk is inclusive.
* If no uptodate block is found, this will return end_blk + 1.
*/
static unsigned ifs_next_uptodate_block(struct folio *folio,
unsigned start_blk, unsigned end_blk)
{
return test_bit(block, ifs->state);
struct iomap_folio_state *ifs = folio->private;
return find_next_bit(ifs->state, end_blk + 1, start_blk);
}
/*
* Find the next non-uptodate block in the folio. end_blk is inclusive.
* If no non-uptodate block is found, this will return end_blk + 1.
*/
static unsigned ifs_next_nonuptodate_block(struct folio *folio,
unsigned start_blk, unsigned end_blk)
{
struct iomap_folio_state *ifs = folio->private;
return find_next_zero_bit(ifs->state, end_blk + 1, start_blk);
}
static bool ifs_set_range_uptodate(struct folio *folio,
@ -277,14 +295,11 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
* to avoid reading in already uptodate ranges.
*/
if (ifs) {
unsigned int i, blocks_skipped;
unsigned int next, blocks_skipped;
/* move forward for each leading block marked uptodate */
for (i = first; i <= last; i++)
if (!ifs_block_is_uptodate(ifs, i))
break;
next = ifs_next_nonuptodate_block(folio, first, last);
blocks_skipped = next - first;
blocks_skipped = i - first;
if (blocks_skipped) {
unsigned long block_offset = *pos & (block_size - 1);
unsigned bytes_skipped =
@ -294,15 +309,15 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
poff += bytes_skipped;
plen -= bytes_skipped;
}
first = i;
first = next;
/* truncate len if we find any trailing uptodate block(s) */
while (++i <= last) {
if (ifs_block_is_uptodate(ifs, i)) {
if (++next <= last) {
next = ifs_next_uptodate_block(folio, next, last);
if (next <= last) {
plen -= iomap_bytes_to_truncate(*pos + plen,
block_bits, last - i + 1);
last = i - 1;
break;
block_bits, last - next + 1);
last = next - 1;
}
}
}
@ -639,7 +654,7 @@ bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
{
struct iomap_folio_state *ifs = folio->private;
struct inode *inode = folio->mapping->host;
unsigned first, last, i;
unsigned first, last;
if (!ifs)
return false;
@ -651,10 +666,7 @@ bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
first = from >> inode->i_blkbits;
last = (from + count - 1) >> inode->i_blkbits;
for (i = first; i <= last; i++)
if (!ifs_block_is_uptodate(ifs, i))
return false;
return true;
return ifs_next_nonuptodate_block(folio, first, last) > last;
}
EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);