[PATCH 11/16] xfs: use BIO_COMPLETE_IN_TASK for bounce buffered read I/Os

[Christoph Hellwig <hch@lst.de>]

Stop using the xfs per-inode work struct for completing read bios, as
unlike writes we don't want to serialize reads on a single inode as
there is no exclusive resource contention for them.

Factor the code for kicking off a read that needs and ioend and the
task context completion into a single helper so that it is split off
the xfs_end_bio machinery, which is not only used for writes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/xfs/xfs_aops.c  | 10 ++++------
 fs/xfs/xfs_file.c  |  8 +-------
 fs/xfs/xfs_ioend.c | 32 +++++++++++++++++++++++++++-----
 fs/xfs/xfs_ioend.h |  2 ++
 4 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index d2cdb7cffa6b..c30e688cfc9f 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -583,12 +583,10 @@ xfs_bio_submit_read(
 	const struct iomap_iter		*iter,
 	struct iomap_read_folio_ctx	*ctx)
 {
-	struct bio			*bio = ctx->read_ctx;
-
-	/* defer read completions to the ioend workqueue */
-	iomap_init_ioend(iter->inode, bio, ctx->read_ctx_file_offset,
-		iomap_ioend_flags(&iter->iomap));
-	iomap_bio_submit_read_endio(iter, ctx, xfs_end_bio);
+	xfs_ioend_submit_read(iter->inode, ctx->read_ctx,
+			ctx->read_ctx_file_offset,
+			iomap_ioend_flags(&iter->iomap));
+	ctx->read_ctx = NULL;
 }
 
 static const struct iomap_read_ops xfs_iomap_read_ops = {
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 0e029db2e85b..077744b3f6c3 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -242,14 +242,8 @@ xfs_dio_read_bounce_submit_io(
 	struct bio		*bio,
 	loff_t			file_offset)
 {
-	struct iomap_ioend	*ioend;
-
-	ioend = iomap_init_ioend(iter->inode, bio, file_offset,
+	xfs_ioend_submit_read(iter->inode, bio, file_offset,
 			iomap_ioend_flags(&iter->iomap) | IOMAP_IOEND_DIRECT);
-	if (ioend->io_flags & IOMAP_IOEND_INTEGRITY)
-		fs_bio_integrity_alloc(bio);
-	bio->bi_end_io = xfs_end_bio;
-	submit_bio(bio);
 }
 
 static const struct iomap_dio_ops xfs_dio_read_bounce_ops = {
diff --git a/fs/xfs/xfs_ioend.c b/fs/xfs/xfs_ioend.c
index 40695d18dac0..37a3ae8066e9 100644
--- a/fs/xfs/xfs_ioend.c
+++ b/fs/xfs/xfs_ioend.c
@@ -16,6 +16,32 @@
 #include "xfs_reflink.h"
 #include "xfs_zone_alloc.h"
 #include "xfs_ioend.h"
+#include <linux/bio-integrity.h>
+
+static void
+xfs_end_io_read(
+	struct bio		*bio)
+{
+	struct iomap_ioend	*ioend = iomap_ioend_from_bio(bio);
+	int			error = blk_status_to_errno(bio->bi_status);
+
+	iomap_finish_ioends(ioend, error);
+}
+
+void
+xfs_ioend_submit_read(
+	struct inode		*inode,
+	struct bio		*bio,
+	loff_t			file_offset,
+	u16			ioend_flags)
+{
+	iomap_init_ioend(inode, bio, file_offset, ioend_flags);
+	if (ioend_flags & IOMAP_IOEND_INTEGRITY)
+		fs_bio_integrity_alloc(bio);
+	bio->bi_end_io = xfs_end_io_read;
+	bio_set_flag(bio, BIO_COMPLETE_IN_TASK);
+	submit_bio(bio);
+}
 
 static void
 xfs_ioend_put_open_zones(
@@ -148,11 +174,7 @@ xfs_end_io(
 			io_list))) {
 		list_del_init(&ioend->io_list);
 		iomap_ioend_try_merge(ioend, &tmp);
-		if (bio_op(&ioend->io_bio) == REQ_OP_READ)
-			iomap_finish_ioends(ioend,
-				blk_status_to_errno(ioend->io_bio.bi_status));
-		else
-			xfs_end_ioend_write(ioend);
+		xfs_end_ioend_write(ioend);
 		cond_resched();
 	}
 }
diff --git a/fs/xfs/xfs_ioend.h b/fs/xfs/xfs_ioend.h
index 525865767fca..7c2a1ea3e6ed 100644
--- a/fs/xfs/xfs_ioend.h
+++ b/fs/xfs/xfs_ioend.h
@@ -12,5 +12,7 @@ static inline bool xfs_ioend_is_append(struct iomap_ioend *ioend)
 }
 
 void xfs_end_bio(struct bio *bio);
+void xfs_ioend_submit_read(struct inode *inode, struct bio *bio,
+		loff_t file_offset, u16 ioend_flags);
 
 #endif /* __XFS_IOEND_H */
-- 
2.53.0