[PATCH 5/6] io_uring: enable use of bio alloc cache

[Jens Axboe <axboe@xxxxxxxxx>]

Mark polled IO as being safe for dipping into the bio allocation
cache, in case the targeted bio_set has it enabled.

This brings an IOPOLL gen2 Optane QD=128 workload from ~3.0M IOPS to
~3.3M IOPS.

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6c65c90131cb..ea387b0741b8 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2736,7 +2736,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		    !kiocb->ki_filp->f_op->iopoll)
 			return -EOPNOTSUPP;
 
-		kiocb->ki_flags |= IOCB_HIPRI;
+		kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
 		kiocb->ki_complete = io_complete_rw_iopoll;
 		req->iopoll_completed = 0;
 	} else {
-- 
2.32.0