[PATCH v14 106/138] iomap: Convert iomap_do_writepage to use a folio

Matthew Wilcox (Oracle)
2021-07-15T05:04:27Z

Writeback an entire folio at a time, and adjust some of the variables
to have more familiar names.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/iomap/buffered-io.c | 49 +++++++++++++++++++-----------------------
1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 8e767aec8d07..0731e2c3f44b 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1296,9 +1296,8 @@ iomap_add_to_ioend(struct inode *inode, loff_t pos, struct folio *folio,
static int
iomap_writepage_map(struct iomap_writepage_ctx *wpc,
struct writeback_control *wbc, struct inode *inode,
- struct page *page, u64 end_offset)
+ struct folio *folio, loff_t end_pos)
{
- struct folio *folio = page_folio(page);
struct iomap_page *iop = to_iomap_page(folio);
struct iomap_ioend *ioend, *next;
unsigned len = i_blocksize(inode);
@@ -1316,7 +1315,7 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
* invalid, grab a new one.
*/
for (i = 0; i < nblocks; i++, pos += len) {
- if (pos >= end_offset)
+ if (pos >= end_pos)
break;
if (iop && !test_bit(i, iop->uptodate))
continue;
@@ -1398,16 +1397,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
static int
iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
{
+ struct folio *folio = page_folio(page);
struct iomap_writepage_ctx *wpc = data;
- struct inode *inode = page->mapping->host;
- pgoff_t end_index;
- u64 end_offset;
- loff_t offset;
+ struct inode *inode = folio->mapping->host;
+ loff_t end_pos, isize;

- trace_iomap_writepage(inode, page_offset(page), PAGE_SIZE);
+ trace_iomap_writepage(inode, folio_pos(folio), folio_size(folio));

/*
- * Refuse to write the page out if we are called from reclaim context.
+ * Refuse to write the folio out if we are called from reclaim context.
*
* This avoids stack overflows when called from deeply used stacks in
* random callers for direct reclaim or memcg reclaim. We explicitly
@@ -1421,10 +1419,10 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
goto redirty;

/*
- * Is this page beyond the end of the file?
+ * Is this folio beyond the end of the file?
*
- * The page index is less than the end_index, adjust the end_offset
- * to the highest offset that this page should represent.
+ * The folio index is less than the end_index, adjust the end_pos
+ * to the highest offset that this folio should represent.
* -----------------------------------------------------
* | file mapping | <EOF> |
* -----------------------------------------------------
@@ -1433,11 +1431,9 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* | desired writeback range | see else |
* ---------------------------------^------------------|
*/
- offset = i_size_read(inode);
- end_index = offset >> PAGE_SHIFT;
- if (page->index < end_index)
- end_offset = (loff_t)(page->index + 1) << PAGE_SHIFT;
- else {
+ isize = i_size_read(inode);
+ end_pos = folio_pos(folio) + folio_size(folio);
+ if (end_pos - 1 >= isize) {
/*
* Check whether the page to write out is beyond or straddles
* i_size or not.
@@ -1449,7 +1445,8 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* | | Straddles |
* ---------------------------------^-----------|--------|
*/
- unsigned offset_into_page = offset & (PAGE_SIZE - 1);
+ size_t poff = offset_in_folio(folio, isize);
+ pgoff_t end_index = isize >> PAGE_SHIFT;

/*
* Skip the page if it is fully outside i_size, e.g. due to a
@@ -1468,8 +1465,8 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* if the page to write is totally beyond the i_size or if it's
* offset is just equal to the EOF.
*/
- if (page->index > end_index ||
- (page->index == end_index && offset_into_page == 0))
+ if (folio->index > end_index ||
+ (folio->index == end_index && poff == 0))
goto redirty;

/*
@@ -1480,17 +1477,15 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* memory is zeroed when mapped, and writes to that region are
* not written out to the file."
*/
- zero_user_segment(page, offset_into_page, PAGE_SIZE);
-
- /* Adjust the end_offset to the end of file */
- end_offset = offset;
+ zero_user_segment(&folio->page, poff, folio_size(folio));
+ end_pos = isize;
}

- return iomap_writepage_map(wpc, wbc, inode, page, end_offset);
+ return iomap_writepage_map(wpc, wbc, inode, folio, end_pos);

redirty:
- redirty_page_for_writepage(wbc, page);
- unlock_page(page);
+ folio_redirty_for_writepage(wbc, folio);
+ folio_unlock(folio);
return 0;
}

--
2.30.2