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From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 4/4] io_uring: sqthread should grab ctx->uring_lock for submissions
Date: Mon,  9 Dec 2019 16:18:54 -0700
Message-ID: <20191209231854.3767-5-axboe@kernel.dk> (raw)
In-Reply-To: <20191209231854.3767-1-axboe@kernel.dk>

We use the mutex to guard against registered file updates, for instance.
Ensure we're safe in accessing that state against concurrent updates.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 662404854571..33e15e925609 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2997,12 +2997,7 @@ static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt,
 		if (req->result == -EAGAIN)
 			return -EAGAIN;
 
-		/* workqueue context doesn't hold uring_lock, grab it now */
-		if (req->in_async)
-			mutex_lock(&ctx->uring_lock);
 		io_iopoll_req_issued(req);
-		if (req->in_async)
-			mutex_unlock(&ctx->uring_lock);
 	}
 
 	return 0;
@@ -3657,7 +3652,9 @@ static int io_sq_thread(void *data)
 		}
 
 		to_submit = min(to_submit, ctx->sq_entries);
+		mutex_lock(&ctx->uring_lock);
 		ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true);
+		mutex_unlock(&ctx->uring_lock);
 		if (ret > 0)
 			inflight += ret;
 	}
-- 
2.24.0


      parent reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09 23:18 [PATCHSET 0/4] io_uring patches for 5.5-rc Jens Axboe
2019-12-09 23:18 ` [PATCH 1/4] io_uring: allow unbreakable links Jens Axboe
2019-12-10 10:13   ` Pavel Begunkov
2019-12-10 15:13     ` Jens Axboe
2019-12-09 23:18 ` [PATCH 2/4] io-wq: remove worker->wait waitqueue Jens Axboe
2019-12-09 23:18 ` [PATCH 3/4] io-wq: briefly spin for new work after finishing work Jens Axboe
2019-12-09 23:18 ` Jens Axboe [this message]

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