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From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 07/11] io_uring: make IORING_POLL_ADD and IORING_POLL_REMOVE deferrable
Date: Tue, 17 Dec 2019 20:27:55 -0700
Message-ID: <20191218032759.13587-8-axboe@kernel.dk> (raw)
In-Reply-To: <20191218032759.13587-1-axboe@kernel.dk>

If we defer these commands as part of a link, we have to make sure that
the SQE data has been read upfront. Integrate the poll add/remove into
the prep handling to make it safe for SQE reuse.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 68 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 54 insertions(+), 14 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index c8d741dd70dd..0ce91165d918 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -289,7 +289,10 @@ struct io_ring_ctx {
  */
 struct io_poll_iocb {
 	struct file			*file;
-	struct wait_queue_head		*head;
+	union {
+		struct wait_queue_head	*head;
+		u64			addr;
+	};
 	__poll_t			events;
 	bool				done;
 	bool				canceled;
@@ -2485,24 +2488,40 @@ static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
 	return -ENOENT;
 }
 
+static int io_poll_remove_prep(struct io_kiocb *req)
+{
+	const struct io_uring_sqe *sqe = req->sqe;
+
+	if (req->flags & REQ_F_PREPPED)
+		return 0;
+	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
+	    sqe->poll_events)
+		return -EINVAL;
+
+	req->poll.addr = READ_ONCE(sqe->addr);
+	req->flags |= REQ_F_PREPPED;
+	return 0;
+}
+
 /*
  * Find a running poll command that matches one specified in sqe->addr,
  * and remove it if found.
  */
 static int io_poll_remove(struct io_kiocb *req)
 {
-	const struct io_uring_sqe *sqe = req->sqe;
 	struct io_ring_ctx *ctx = req->ctx;
+	u64 addr;
 	int ret;
 
-	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
-		return -EINVAL;
-	if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
-	    sqe->poll_events)
-		return -EINVAL;
+	ret = io_poll_remove_prep(req);
+	if (ret)
+		return ret;
 
+	addr = req->poll.addr;
 	spin_lock_irq(&ctx->completion_lock);
-	ret = io_poll_cancel(ctx, READ_ONCE(sqe->addr));
+	ret = io_poll_cancel(ctx, addr);
 	spin_unlock_irq(&ctx->completion_lock);
 
 	io_cqring_add_event(req, ret);
@@ -2637,16 +2656,14 @@ static void io_poll_req_insert(struct io_kiocb *req)
 	hlist_add_head(&req->hash_node, list);
 }
 
-static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
+static int io_poll_add_prep(struct io_kiocb *req)
 {
 	const struct io_uring_sqe *sqe = req->sqe;
 	struct io_poll_iocb *poll = &req->poll;
-	struct io_ring_ctx *ctx = req->ctx;
-	struct io_poll_table ipt;
-	bool cancel = false;
-	__poll_t mask;
 	u16 events;
 
+	if (req->flags & REQ_F_PREPPED)
+		return 0;
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
 		return -EINVAL;
 	if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
@@ -2654,9 +2671,26 @@ static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
 	if (!poll->file)
 		return -EBADF;
 
-	INIT_IO_WORK(&req->work, io_poll_complete_work);
+	req->flags |= REQ_F_PREPPED;
 	events = READ_ONCE(sqe->poll_events);
 	poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
+	return 0;
+}
+
+static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
+{
+	struct io_poll_iocb *poll = &req->poll;
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_poll_table ipt;
+	bool cancel = false;
+	__poll_t mask;
+	int ret;
+
+	ret = io_poll_add_prep(req);
+	if (ret)
+		return ret;
+
+	INIT_IO_WORK(&req->work, io_poll_complete_work);
 	INIT_HLIST_NODE(&req->hash_node);
 
 	poll->head = NULL;
@@ -3024,6 +3058,12 @@ static int io_req_defer_prep(struct io_kiocb *req)
 		io_req_map_rw(req, ret, iovec, inline_vecs, &iter);
 		ret = 0;
 		break;
+	case IORING_OP_POLL_ADD:
+		ret = io_poll_add_prep(req);
+		break;
+	case IORING_OP_POLL_REMOVE:
+		ret = io_poll_remove_prep(req);
+		break;
 	case IORING_OP_FSYNC:
 		ret = io_prep_fsync(req);
 		break;
-- 
2.24.1


  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-18  3:27 [PATCHSET v2] io_uring fixes for 5.5-rc3 Jens Axboe
2019-12-18  3:27 ` [PATCH 01/11] io_uring: fix stale comment and a few typos Jens Axboe
2019-12-18  3:27 ` [PATCH 02/11] io_uring: fix sporadic -EFAULT from IORING_OP_RECVMSG Jens Axboe
2019-12-18  3:27 ` [PATCH 03/11] io_uring: fix pre-prepped issue with force_nonblock == true Jens Axboe
2019-12-18  3:27 ` [PATCH 04/11] io_uring: remove 'sqe' parameter to the OP helpers that take it Jens Axboe
2019-12-18  3:27 ` [PATCH 05/11] io_uring: any deferred command must have stable sqe data Jens Axboe
2019-12-18  3:27 ` [PATCH 06/11] io_uring: make HARDLINK imply LINK Jens Axboe
2019-12-18  3:27 ` Jens Axboe [this message]
2019-12-18  3:27 ` [PATCH 08/11] io_uring: make IORING_OP_CANCEL_ASYNC deferrable Jens Axboe
2019-12-18  3:27 ` [PATCH 09/11] io_uring: make IORING_OP_TIMEOUT_REMOVE deferrable Jens Axboe
2019-12-18  3:27 ` [PATCH 10/11] io_uring: read opcode and user_data from SQE exactly once Jens Axboe
2019-12-18  3:27 ` [PATCH 11/11] io_uring: warn about unhandled opcode Jens Axboe

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