[RFC PATCH 08/10] iomap: Reorder functions

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Move the ioend submission functions earlier in the file so write_iter
can submit ioends without requiring forward declarations.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/iomap/buffered-io.c | 204 ++++++++++++++++++++---------------------
 1 file changed, 101 insertions(+), 103 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 4aa2209fb003..6c540390eec3 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -665,6 +665,107 @@ static struct iomap_ioend *iomap_add_to_ioend(struct inode *inode,
 	return ioend;
 }
 
+static void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
+		size_t len, int error)
+{
+	struct iomap_page *iop = to_iomap_page(folio);
+
+	if (error) {
+		folio_set_error(folio);
+		mapping_set_error(inode->i_mapping, error);
+	}
+
+	WARN_ON_ONCE(i_blocks_per_folio(inode, folio) > 1 && !iop);
+	WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) <= 0);
+
+	if (!iop || atomic_sub_and_test(len, &iop->write_bytes_pending))
+		folio_end_writeback(folio);
+}
+
+/*
+ * We're now finished for good with this ioend structure.  Update the page
+ * state, release holds on bios, and finally free up memory.  Do not use the
+ * ioend after this.
+ */
+static u32 iomap_finish_ioend(struct iomap_ioend *ioend, int error)
+{
+	struct inode *inode = ioend->io_inode;
+	struct bio *bio = &ioend->io_inline_bio;
+	struct bio *last = ioend->io_bio, *next;
+	u64 start = bio->bi_iter.bi_sector;
+	loff_t offset = ioend->io_offset;
+	bool quiet = bio_flagged(bio, BIO_QUIET);
+	u32 folio_count = 0;
+
+	for (bio = &ioend->io_inline_bio; bio; bio = next) {
+		struct folio_iter fi;
+
+		/*
+		 * For the last bio, bi_private points to the ioend, so we
+		 * need to explicitly end the iteration here.
+		 */
+		if (bio == last)
+			next = NULL;
+		else
+			next = bio->bi_private;
+
+		/* walk all folios in bio, ending page IO on them */
+		bio_for_each_folio_all(fi, bio) {
+			iomap_finish_folio_write(inode, fi.folio, fi.length,
+					error);
+			folio_count++;
+		}
+		bio_put(bio);
+	}
+	/* The ioend has been freed by bio_put() */
+
+	if (unlikely(error && !quiet)) {
+		printk_ratelimited(KERN_ERR
+"%s: writeback error on inode %lu, offset %lld, sector %llu",
+			inode->i_sb->s_id, inode->i_ino, offset, start);
+	}
+	return folio_count;
+}
+
+static void iomap_writepage_end_bio(struct bio *bio)
+{
+	struct iomap_ioend *ioend = bio->bi_private;
+
+	iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status));
+}
+
+/*
+ * Submit the final bio for an ioend.
+ *
+ * If @error is non-zero, it means that we have a situation where some part of
+ * the submission process has failed after we've marked pages for writeback
+ * and unlocked them.  In this situation, we need to fail the bio instead of
+ * submitting it.  This typically only happens on a filesystem shutdown.
+ */
+static int iomap_submit_ioend(struct iomap_writepage_ctx *wpc,
+		struct iomap_ioend *ioend, int error)
+{
+	ioend->io_bio->bi_private = ioend;
+	ioend->io_bio->bi_end_io = iomap_writepage_end_bio;
+
+	if (wpc && wpc->ops->prepare_ioend)
+		error = wpc->ops->prepare_ioend(ioend, error);
+	if (error) {
+		/*
+		 * If we're failing the IO now, just mark the ioend with an
+		 * error and finish it.  This will run IO completion immediately
+		 * as there is only one reference to the ioend at this point in
+		 * time.
+		 */
+		ioend->io_bio->bi_status = errno_to_blk_status(error);
+		bio_endio(ioend->io_bio);
+		return error;
+	}
+
+	submit_bio(ioend->io_bio);
+	return 0;
+}
+
 static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
 		size_t len, struct folio *folio)
 {
@@ -1126,69 +1227,6 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
 }
 EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
 
-static void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
-		size_t len, int error)
-{
-	struct iomap_page *iop = to_iomap_page(folio);
-
-	if (error) {
-		folio_set_error(folio);
-		mapping_set_error(inode->i_mapping, error);
-	}
-
-	WARN_ON_ONCE(i_blocks_per_folio(inode, folio) > 1 && !iop);
-	WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) <= 0);
-
-	if (!iop || atomic_sub_and_test(len, &iop->write_bytes_pending))
-		folio_end_writeback(folio);
-}
-
-/*
- * We're now finished for good with this ioend structure.  Update the page
- * state, release holds on bios, and finally free up memory.  Do not use the
- * ioend after this.
- */
-static u32
-iomap_finish_ioend(struct iomap_ioend *ioend, int error)
-{
-	struct inode *inode = ioend->io_inode;
-	struct bio *bio = &ioend->io_inline_bio;
-	struct bio *last = ioend->io_bio, *next;
-	u64 start = bio->bi_iter.bi_sector;
-	loff_t offset = ioend->io_offset;
-	bool quiet = bio_flagged(bio, BIO_QUIET);
-	u32 folio_count = 0;
-
-	for (bio = &ioend->io_inline_bio; bio; bio = next) {
-		struct folio_iter fi;
-
-		/*
-		 * For the last bio, bi_private points to the ioend, so we
-		 * need to explicitly end the iteration here.
-		 */
-		if (bio == last)
-			next = NULL;
-		else
-			next = bio->bi_private;
-
-		/* walk all folios in bio, ending page IO on them */
-		bio_for_each_folio_all(fi, bio) {
-			iomap_finish_folio_write(inode, fi.folio, fi.length,
-					error);
-			folio_count++;
-		}
-		bio_put(bio);
-	}
-	/* The ioend has been freed by bio_put() */
-
-	if (unlikely(error && !quiet)) {
-		printk_ratelimited(KERN_ERR
-"%s: writeback error on inode %lu, offset %lld, sector %llu",
-			inode->i_sb->s_id, inode->i_ino, offset, start);
-	}
-	return folio_count;
-}
-
 /*
  * Ioend completion routine for merged bios. This can only be called from task
  * contexts as merged ioends can be of unbound length. Hence we have to break up
@@ -1289,46 +1327,6 @@ iomap_sort_ioends(struct list_head *ioend_list)
 }
 EXPORT_SYMBOL_GPL(iomap_sort_ioends);
 
-static void iomap_writepage_end_bio(struct bio *bio)
-{
-	struct iomap_ioend *ioend = bio->bi_private;
-
-	iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status));
-}
-
-/*
- * Submit the final bio for an ioend.
- *
- * If @error is non-zero, it means that we have a situation where some part of
- * the submission process has failed after we've marked pages for writeback
- * and unlocked them.  In this situation, we need to fail the bio instead of
- * submitting it.  This typically only happens on a filesystem shutdown.
- */
-static int
-iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend,
-		int error)
-{
-	ioend->io_bio->bi_private = ioend;
-	ioend->io_bio->bi_end_io = iomap_writepage_end_bio;
-
-	if (wpc && wpc->ops->prepare_ioend)
-		error = wpc->ops->prepare_ioend(ioend, error);
-	if (error) {
-		/*
-		 * If we're failing the IO now, just mark the ioend with an
-		 * error and finish it.  This will run IO completion immediately
-		 * as there is only one reference to the ioend at this point in
-		 * time.
-		 */
-		ioend->io_bio->bi_status = errno_to_blk_status(error);
-		bio_endio(ioend->io_bio);
-		return error;
-	}
-
-	submit_bio(ioend->io_bio);
-	return 0;
-}
-
 /*
  * We implement an immediate ioend submission policy here to avoid needing to
  * chain multiple ioends and hence nest mempool allocations which can violate
-- 
2.34.1