[PATCH v15 09/17] iomap: Use folio offsets instead of page offsets

Matthew Wilcox (Oracle)
2021-07-19T22:23:47Z

Pass a folio around instead of the page, and make sure the offset
is relative to the start of the folio instead of the start of a page.
Also use size_t for offset & length to make it clear that these are byte
counts, and to support >2GB folios in the future.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/iomap/buffered-io.c | 83 ++++++++++++++++++++++--------------------
1 file changed, 43 insertions(+), 40 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 62d8ebcda429..0f70bd185c2a 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -75,18 +75,18 @@ static void iomap_page_release(struct folio *folio)
}

/*
- * Calculate the range inside the page that we actually need to read.
+ * Calculate the range inside the folio that we actually need to read.
*/
-static void
-iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
- loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
+static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
+ loff_t *pos, loff_t length, size_t *offp, size_t *lenp)
{
+ struct iomap_page *iop = to_iomap_page(folio);
loff_t orig_pos = *pos;
loff_t isize = i_size_read(inode);
unsigned block_bits = inode->i_blkbits;
unsigned block_size = (1 << block_bits);
- unsigned poff = offset_in_page(*pos);
- unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
+ size_t poff = offset_in_folio(folio, *pos);
+ size_t plen = min_t(loff_t, folio_size(folio) - poff, length);
unsigned first = poff >> block_bits;
unsigned last = (poff + plen - 1) >> block_bits;

@@ -124,7 +124,7 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
* page cache for blocks that are entirely outside of i_size.
*/
if (orig_pos <= isize && orig_pos + length > isize) {
- unsigned end = offset_in_page(isize - 1) >> block_bits;
+ unsigned end = offset_in_folio(folio, isize - 1) >> block_bits;

if (first <= end && last > end)
plen -= (last - end) * block_size;
@@ -134,31 +134,31 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
*lenp = plen;
}

-static void iomap_iop_set_range_uptodate(struct page *page,
- struct iomap_page *iop, unsigned off, unsigned len)
+static void iomap_iop_set_range_uptodate(struct folio *folio,
+ struct iomap_page *iop, size_t off, size_t len)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = folio->mapping->host;
unsigned first = off >> inode->i_blkbits;
unsigned last = (off + len - 1) >> inode->i_blkbits;
unsigned long flags;

spin_lock_irqsave(&iop->uptodate_lock, flags);
bitmap_set(iop->uptodate, first, last - first + 1);
- if (bitmap_full(iop->uptodate, i_blocks_per_page(inode, page)))
- SetPageUptodate(page);
+ if (bitmap_full(iop->uptodate, i_blocks_per_folio(inode, folio)))
+ folio_mark_uptodate(folio);
spin_unlock_irqrestore(&iop->uptodate_lock, flags);
}

-static void iomap_set_range_uptodate(struct page *page,
- struct iomap_page *iop, unsigned off, unsigned len)
+static void iomap_set_range_uptodate(struct folio *folio,
+ struct iomap_page *iop, size_t off, size_t len)
{
- if (PageError(page))
+ if (folio_test_error(folio))
return;

if (iop)
- iomap_iop_set_range_uptodate(page, iop, off, len);
+ iomap_iop_set_range_uptodate(folio, iop, off, len);
else
- SetPageUptodate(page);
+ folio_mark_uptodate(folio);
}

static void
@@ -169,15 +169,17 @@ iomap_read_page_end_io(struct bio_vec *bvec, int error)
struct iomap_page *iop = to_iomap_page(folio);

if (unlikely(error)) {
- ClearPageUptodate(page);
- SetPageError(page);
+ folio_clear_uptodate(folio);
+ folio_set_error(folio);
} else {
- iomap_set_range_uptodate(page, iop, bvec->bv_offset,
- bvec->bv_len);
+ size_t off = (page - &folio->page) * PAGE_SIZE +
+ bvec->bv_offset;
+
+ iomap_set_range_uptodate(folio, iop, off, bvec->bv_len);
}

if (!iop || atomic_sub_and_test(bvec->bv_len, &iop->read_bytes_pending))
- unlock_page(page);
+ folio_unlock(folio);
}

static void
@@ -238,7 +240,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
struct iomap_page *iop;
bool same_page = false, is_contig = false;
loff_t orig_pos = pos;
- unsigned poff, plen;
+ size_t poff, plen;
sector_t sector;

if (iomap->type == IOMAP_INLINE) {
@@ -249,13 +251,13 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,

/* zero post-eof blocks as the page may be mapped */
iop = iomap_page_create(inode, folio);
- iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
+ iomap_adjust_read_range(inode, folio, &pos, length, &poff, &plen);
if (plen == 0)
goto done;

if (iomap_block_needs_zeroing(inode, iomap, pos)) {
- zero_user(page, poff, plen);
- iomap_set_range_uptodate(page, iop, poff, plen);
+ zero_user(&folio->page, poff, plen);
+ iomap_set_range_uptodate(folio, iop, poff, plen);
goto done;
}

@@ -266,7 +268,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
/* Try to merge into a previous segment if we can */
sector = iomap_sector(iomap, pos);
if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
- if (__bio_try_merge_page(ctx->bio, page, plen, poff,
+ if (__bio_try_merge_page(ctx->bio, &folio->page, plen, poff,
&same_page))
goto done;
is_contig = true;
@@ -298,7 +300,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
ctx->bio->bi_end_io = iomap_read_end_io;
}

- bio_add_page(ctx->bio, page, plen, poff);
+ bio_add_folio(ctx->bio, folio, plen, poff);
done:
/*
* Move the caller beyond our range so that it keeps making progress.
@@ -533,9 +535,8 @@ iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
truncate_pagecache_range(inode, max(pos, i_size), pos + len);
}

-static int
-iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
- unsigned plen, struct iomap *iomap)
+static int iomap_read_folio_sync(loff_t block_start, struct folio *folio,
+ size_t poff, size_t plen, struct iomap *iomap)
{
struct bio_vec bvec;
struct bio bio;
@@ -544,7 +545,7 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
bio.bi_opf = REQ_OP_READ;
bio.bi_iter.bi_sector = iomap_sector(iomap, block_start);
bio_set_dev(&bio, iomap->bdev);
- __bio_add_page(&bio, page, plen, poff);
+ bio_add_folio(&bio, folio, plen, poff);
return submit_bio_wait(&bio);
}

@@ -557,14 +558,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
loff_t block_size = i_blocksize(inode);
loff_t block_start = round_down(pos, block_size);
loff_t block_end = round_up(pos + len, block_size);
- unsigned from = offset_in_page(pos), to = from + len, poff, plen;
+ size_t from = offset_in_folio(folio, pos), to = from + len;
+ size_t poff, plen;

- if (PageUptodate(page))
+ if (folio_test_uptodate(folio))
return 0;
- ClearPageError(page);
+ folio_clear_error(folio);

do {
- iomap_adjust_read_range(inode, iop, &block_start,
+ iomap_adjust_read_range(inode, folio, &block_start,
block_end - block_start, &poff, &plen);
if (plen == 0)
break;
@@ -577,14 +579,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
if (iomap_block_needs_zeroing(inode, srcmap, block_start)) {
if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE))
return -EIO;
- zero_user_segments(page, poff, from, to, poff + plen);
+ zero_user_segments(&folio->page, poff, from, to,
+ poff + plen);
} else {
- int status = iomap_read_page_sync(block_start, page,
+ int status = iomap_read_folio_sync(block_start, folio,
poff, plen, srcmap);
if (status)
return status;
}
- iomap_set_range_uptodate(page, iop, poff, plen);
+ iomap_set_range_uptodate(folio, iop, poff, plen);
} while ((block_start += plen) < block_end);

return 0;
@@ -663,7 +666,7 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
*/
if (unlikely(copied < len && !PageUptodate(page)))
return 0;
- iomap_set_range_uptodate(page, iop, offset_in_page(pos), len);
+ iomap_set_range_uptodate(folio, iop, offset_in_folio(folio, pos), len);
__set_page_dirty_nobuffers(page);
return copied;
}
--
2.30.2