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Subject[PATCH v3 17/25] iomap: Convert iomap_write_begin() and iomap_write_end() to folios
Date
These functions still only work in PAGE_SIZE chunks, but there are
fewer conversions from tail to head pages as a result of this patch.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/iomap/buffered-io.c | 73 ++++++++++++++++++++----------------------
1 file changed, 34 insertions(+), 39 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 47cf558244f4..975a4a6aeca0 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -550,9 +550,8 @@ static int iomap_read_folio_sync(loff_t block_start, struct folio *folio,
}

static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
- unsigned len, struct page *page)
+ size_t len, struct folio *folio)
{
- struct folio *folio = page_folio(page);
const struct iomap *srcmap = iomap_iter_srcmap(iter);
struct iomap_page *iop = iomap_page_create(iter->inode, folio);
loff_t block_size = i_blocksize(iter->inode);
@@ -593,10 +592,8 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
}

static int iomap_write_begin_inline(const struct iomap_iter *iter,
- struct page *page)
+ struct folio *folio)
{
- struct folio *folio = page_folio(page);
-
/* needs more work for the tailpacking case; disable for now */
if (WARN_ON_ONCE(iomap_iter_srcmap(iter)->offset != 0))
return -EIO;
@@ -604,12 +601,12 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter,
}

static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
- unsigned len, struct page **pagep)
+ size_t len, struct folio **foliop)
{
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
- struct page *page;
struct folio *folio;
+ unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;
int status = 0;

BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);
@@ -620,7 +617,7 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
return -EINTR;

if (!mapping_large_folio_support(iter->inode->i_mapping))
- len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos));
+ len = min(len, PAGE_SIZE - offset_in_page(pos));

if (page_ops && page_ops->page_prepare) {
status = page_ops->page_prepare(iter->inode, pos, len);
@@ -628,32 +625,31 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
return status;
}

- page = grab_cache_page_write_begin(iter->inode->i_mapping,
- pos >> PAGE_SHIFT, AOP_FLAG_NOFS);
- if (!page) {
+ folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
+ fgp, mapping_gfp_mask(iter->inode->i_mapping));
+ if (!folio) {
status = -ENOMEM;
goto out_no_page;
}
- folio = page_folio(page);
if (pos + len > folio_pos(folio) + folio_size(folio))
len = folio_pos(folio) + folio_size(folio) - pos;

if (srcmap->type == IOMAP_INLINE)
- status = iomap_write_begin_inline(iter, page);
+ status = iomap_write_begin_inline(iter, folio);
else if (srcmap->flags & IOMAP_F_BUFFER_HEAD)
status = __block_write_begin_int(folio, pos, len, NULL, srcmap);
else
- status = __iomap_write_begin(iter, pos, len, page);
+ status = __iomap_write_begin(iter, pos, len, folio);

if (unlikely(status))
goto out_unlock;

- *pagep = page;
+ *foliop = folio;
return 0;

out_unlock:
- unlock_page(page);
- put_page(page);
+ folio_unlock(folio);
+ folio_put(folio);
iomap_write_failed(iter->inode, pos, len);

out_no_page:
@@ -663,11 +659,10 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
}

static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
- size_t copied, struct page *page)
+ size_t copied, struct folio *folio)
{
- struct folio *folio = page_folio(page);
struct iomap_page *iop = to_iomap_page(folio);
- flush_dcache_page(page);
+ flush_dcache_folio(folio);

/*
* The blocks that were entirely written will now be uptodate, so we
@@ -680,10 +675,10 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
* non-uptodate page as a zero-length write, and force the caller to
* redo the whole thing.
*/
- if (unlikely(copied < len && !PageUptodate(page)))
+ if (unlikely(copied < len && !folio_test_uptodate(folio)))
return 0;
iomap_set_range_uptodate(folio, iop, offset_in_folio(folio, pos), len);
- __set_page_dirty_nobuffers(page);
+ filemap_dirty_folio(inode->i_mapping, folio);
return copied;
}

@@ -707,7 +702,7 @@ static size_t iomap_write_end_inline(const struct iomap_iter *iter,

/* Returns the number of bytes copied. May be 0. Cannot be an errno. */
static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
- size_t copied, struct page *page)
+ size_t copied, struct folio *folio)
{
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
@@ -715,12 +710,12 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
size_t ret;

if (srcmap->type == IOMAP_INLINE) {
- ret = iomap_write_end_inline(iter, page, pos, copied);
+ ret = iomap_write_end_inline(iter, &folio->page, pos, copied);
} else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
- copied, page, NULL);
+ copied, &folio->page, NULL);
} else {
- ret = __iomap_write_end(iter->inode, pos, len, copied, page);
+ ret = __iomap_write_end(iter->inode, pos, len, copied, folio);
}

/*
@@ -732,13 +727,13 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
i_size_write(iter->inode, pos + ret);
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
}
- unlock_page(page);
+ folio_unlock(folio);

if (old_size < pos)
pagecache_isize_extended(iter->inode, old_size, pos);
if (page_ops && page_ops->page_done)
- page_ops->page_done(iter->inode, pos, ret, page);
- put_page(page);
+ page_ops->page_done(iter->inode, pos, ret, &folio->page);
+ folio_put(folio);

if (ret < len)
iomap_write_failed(iter->inode, pos, len);
@@ -753,6 +748,7 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
long status = 0;

do {
+ struct folio *folio;
struct page *page;
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
@@ -776,16 +772,17 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
break;
}

- status = iomap_write_begin(iter, pos, bytes, &page);
+ status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
break;

+ page = folio_file_page(folio, pos >> PAGE_SHIFT);
if (mapping_writably_mapped(iter->inode->i_mapping))
flush_dcache_page(page);

copied = copy_page_from_iter_atomic(page, offset, bytes, i);

- status = iomap_write_end(iter, pos, bytes, copied, page);
+ status = iomap_write_end(iter, pos, bytes, copied, folio);

if (unlikely(copied != status))
iov_iter_revert(i, copied - status);
@@ -851,13 +848,13 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
do {
unsigned long offset = offset_in_page(pos);
unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length);
- struct page *page;
+ struct folio *folio;

- status = iomap_write_begin(iter, pos, bytes, &page);
+ status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
return status;

- status = iomap_write_end(iter, pos, bytes, bytes, page);
+ status = iomap_write_end(iter, pos, bytes, bytes, folio);
if (WARN_ON_ONCE(status == 0))
return -EIO;

@@ -894,15 +891,13 @@ EXPORT_SYMBOL_GPL(iomap_file_unshare);
static s64 __iomap_zero_iter(struct iomap_iter *iter, loff_t pos, u64 length)
{
struct folio *folio;
- struct page *page;
int status;
size_t offset;
- unsigned bytes = min_t(u64, UINT_MAX, length);
+ size_t bytes = min_t(u64, SIZE_MAX, length);

- status = iomap_write_begin(iter, pos, bytes, &page);
+ status = iomap_write_begin(iter, pos, bytes, &folio);
if (status)
return status;
- folio = page_folio(page);

offset = offset_in_folio(folio, pos);
if (bytes > folio_size(folio) - offset)
@@ -911,7 +906,7 @@ static s64 __iomap_zero_iter(struct iomap_iter *iter, loff_t pos, u64 length)
folio_zero_range(folio, offset, bytes);
folio_mark_accessed(folio);

- return iomap_write_end(iter, pos, bytes, bytes, page);
+ return iomap_write_end(iter, pos, bytes, bytes, folio);
}

static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
--
2.33.0
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