[PATCH v3 4/9] Introduce IOCB_SWAP kiocb flag to trigger REQ_SWAP

[David Howells]

Introduce an IOCB_SWAP flag for the kiocb struct such that the REQ_SWAP
will get set on lower level operation structures in generic code.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: Christoph Hellwig <hch@xxxxxx>
cc: Darrick J. Wong <djwong@xxxxxxxxxx>
cc: linux-xfs@xxxxxxxxxxxxxxx
cc: linux-block@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
cc: linux-mm@xxxxxxxxx
---

 fs/direct-io.c      |    2 ++
 include/linux/bio.h |    2 ++
 include/linux/fs.h  |    1 +
 3 files changed, 5 insertions(+)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index b2e86e739d7a..76eec0a68fa4 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1216,6 +1216,8 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 	}
 	if (iocb->ki_flags & IOCB_HIPRI)
 		dio->op_flags |= REQ_HIPRI;
+	if (iocb->ki_flags & IOCB_SWAP)
+		dio->op_flags |= REQ_SWAP;
 
 	/*
 	 * For AIO O_(D)SYNC writes we need to defer completions to a workqueue
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 00952e92eae1..b01133727494 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -787,6 +787,8 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 	bio->bi_opf |= REQ_HIPRI;
 	if (!is_sync_kiocb(kiocb))
 		bio->bi_opf |= REQ_NOWAIT;
+	if (kiocb->ki_flags & IOCB_SWAP)
+		bio->bi_opf |= REQ_SWAP;
 }
 
 struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c909ca6c0eb6..c20f4423e2f1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -321,6 +321,7 @@ enum rw_hint {
 #define IOCB_NOIO		(1 << 20)
 /* can use bio alloc cache */
 #define IOCB_ALLOC_CACHE	(1 << 21)
+#define IOCB_SWAP		(1 << 22)	/* Operation on a swapfile */
 
 struct kiocb {
 	struct file		*ki_filp;