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From:   Jens Axboe <axboe@kernel.dk>
To:     io-uring@vger.kernel.org
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, akpm@linux-foundation.org,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 02/15] io_uring: always plug for any number of IOs
Date:   Thu, 18 Jun 2020 08:43:42 -0600
Message-Id: <20200618144355.17324-3-axboe@kernel.dk>
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Currently we only plug if we're doing more than two request. We're going
to be relying on always having the plug there to pass down information,
so plug unconditionally.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b14a8e6a0e15..ca78dd7c79da 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -676,7 +676,6 @@ struct io_kiocb {
 	};
 };
 
-#define IO_PLUG_THRESHOLD		2
 #define IO_IOPOLL_BATCH			8
 
 struct io_submit_state {
@@ -5914,7 +5913,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 			  struct file *ring_file, int ring_fd)
 {
-	struct io_submit_state state, *statep = NULL;
+	struct io_submit_state state;
 	struct io_kiocb *link = NULL;
 	int i, submitted = 0;
 
@@ -5931,10 +5930,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 	if (!percpu_ref_tryget_many(&ctx->refs, nr))
 		return -EAGAIN;
 
-	if (nr > IO_PLUG_THRESHOLD) {
-		io_submit_state_start(&state, nr);
-		statep = &state;
-	}
+	io_submit_state_start(&state, nr);
 
 	ctx->ring_fd = ring_fd;
 	ctx->ring_file = ring_file;
@@ -5949,14 +5945,14 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 			io_consume_sqe(ctx);
 			break;
 		}
-		req = io_alloc_req(ctx, statep);
+		req = io_alloc_req(ctx, &state);
 		if (unlikely(!req)) {
 			if (!submitted)
 				submitted = -EAGAIN;
 			break;
 		}
 
-		err = io_init_req(ctx, req, sqe, statep);
+		err = io_init_req(ctx, req, sqe, &state);
 		io_consume_sqe(ctx);
 		/* will complete beyond this point, count as submitted */
 		submitted++;
@@ -5982,8 +5978,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 	}
 	if (link)
 		io_queue_link_head(link);
-	if (statep)
-		io_submit_state_end(&state);
+	io_submit_state_end(&state);
 
 	 /* Commit SQ ring head once we've consumed and submitted all SQEs */
 	io_commit_sqring(ctx);
-- 
2.27.0