[PATCH v3 2/6] iomap: introduce and propagate write_stream

[Kanchan Joshi <joshi.k@samsung.com>]

Add a new write_stream field to struct iomap. Existing hole is used to
place the new field.
Propagate write_stream from iomap to bio in both direct I/O and buffered
writeback paths.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
---
 fs/iomap/direct-io.c  | 1 +
 fs/iomap/ioend.c      | 3 +++
 include/linux/iomap.h | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index b36ee619cdcd..455fd5d97d25 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -348,6 +348,7 @@ static ssize_t iomap_dio_bio_iter_one(struct iomap_iter *iter,
 	fscrypt_set_bio_crypt_ctx(bio, iter->inode, pos, GFP_KERNEL);
 	bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos);
 	bio->bi_write_hint = iter->inode->i_write_hint;
+	bio->bi_write_stream = iter->iomap.write_stream;
 	bio->bi_ioprio = dio->iocb->ki_ioprio;
 	bio->bi_private = dio;
 	bio->bi_end_io = iomap_dio_bio_end_io;
diff --git a/fs/iomap/ioend.c b/fs/iomap/ioend.c
index acf3cf98b23a..56ed5ba6a421 100644
--- a/fs/iomap/ioend.c
+++ b/fs/iomap/ioend.c
@@ -164,6 +164,7 @@ static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc,
 			       GFP_NOFS, &iomap_ioend_bioset);
 	bio->bi_iter.bi_sector = iomap_sector(&wpc->iomap, pos);
 	bio->bi_write_hint = wpc->inode->i_write_hint;
+	bio->bi_write_stream = wpc->iomap.write_stream;
 	wbc_init_bio(wpc->wbc, bio);
 	wpc->nr_folios = 0;
 	return iomap_init_ioend(wpc->inode, bio, pos, ioend_flags);
@@ -187,6 +188,8 @@ static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos,
 	if (!(wpc->iomap.flags & IOMAP_F_ANON_WRITE) &&
 	    iomap_sector(&wpc->iomap, pos) != bio_end_sector(&ioend->io_bio))
 		return false;
+	if (wpc->iomap.write_stream != ioend->io_bio.bi_write_stream)
+		return false;
 	/*
 	 * Limit ioend bio chain lengths to minimise IO completion latency. This
 	 * also prevents long tight loops ending page writeback on all the
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 2c5685adf3a9..44583429ffa4 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -120,6 +120,8 @@ struct iomap {
 	u64			length;	/* length of mapping, bytes */
 	u16			type;	/* type of mapping */
 	u16			flags;	/* flags for mapping */
+	u8			write_stream; /* write stream for I/O */
+	/* 3 bytes padding hole here */
 	struct block_device	*bdev;	/* block device for I/O */
 	struct dax_device	*dax_dev; /* dax_dev for dax operations */
 	void			*inline_data;
-- 
2.25.1