[PATCH 4/5] io_uring: add support for IORING_ASYNC_CANCEL_ALL

[Jens Axboe <axboe@kernel.dk>]

The current cancelation will lookup and cancel the first request it
finds based on the key passed in. Add a flag that allows to cancel any
request that matches they key. It completes with either -ENOENT if none
were found, or res > 0 for the number of entries canceled.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c                 | 60 +++++++++++++++++++++++++----------
 include/uapi/linux/io_uring.h |  7 ++++
 2 files changed, 50 insertions(+), 17 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6dcf3ad7ee99..c7e5d60fbbe5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -568,6 +568,7 @@ struct io_sync {
 struct io_cancel {
 	struct file			*file;
 	u64				addr;
+	u32				flags;
 };
 
 struct io_timeout {
@@ -6319,6 +6320,7 @@ static bool io_poll_disarm(struct io_kiocb *req)
 struct io_cancel_data {
 	struct io_ring_ctx *ctx;
 	u64 data;
+	u32 flags;
 };
 
 static int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
@@ -6774,7 +6776,8 @@ static int io_async_cancel_one(struct io_uring_task *tctx,
 	if (!tctx || !tctx->io_wq)
 		return -ENOENT;
 
-	cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, cd, false);
+	cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, cd,
+					cd->flags & IORING_ASYNC_CANCEL_ALL);
 	switch (cancel_ret) {
 	case IO_WQ_CANCEL_OK:
 		ret = 0;
@@ -6825,27 +6828,34 @@ static int io_async_cancel_prep(struct io_kiocb *req,
 		return -EINVAL;
 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
 		return -EINVAL;
-	if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags ||
-	    sqe->splice_fd_in)
+	if (sqe->ioprio || sqe->off || sqe->len || sqe->splice_fd_in)
 		return -EINVAL;
 
 	req->cancel.addr = READ_ONCE(sqe->addr);
+	req->cancel.flags = READ_ONCE(sqe->cancel_flags);
+	if (req->cancel.flags & ~IORING_ASYNC_CANCEL_ALL)
+		return -EINVAL;
+
 	return 0;
 }
 
-static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
+static int __io_async_cancel(struct io_cancel_data *cd, struct io_kiocb *req,
+			     unsigned int issue_flags)
 {
-	struct io_ring_ctx *ctx = req->ctx;
-	struct io_cancel_data cd = {
-		.ctx	= ctx,
-		.data	= req->cancel.addr,
-	};
+	bool cancel_all = cd->flags & IORING_ASYNC_CANCEL_ALL;
+	struct io_ring_ctx *ctx = cd->ctx;
 	struct io_tctx_node *node;
-	int ret;
+	int ret, nr = 0;
 
-	ret = io_try_cancel(req, &cd);
-	if (ret != -ENOENT)
-		goto done;
+	do {
+		ret = io_try_cancel(req, cd);
+		if (ret == -ENOENT)
+			break;
+		if (!cancel_all)
+			return ret;
+		nr++;
+		io_run_task_work();
+	} while (1);
 
 	/* slow path, try all io-wq's */
 	io_ring_submit_lock(ctx, issue_flags);
@@ -6853,12 +6863,28 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
 		struct io_uring_task *tctx = node->task->io_uring;
 
-		ret = io_async_cancel_one(tctx, &cd);
-		if (ret != -ENOENT)
-			break;
+		ret = io_async_cancel_one(tctx, cd);
+		if (ret != -ENOENT) {
+			if (!cancel_all)
+				break;
+			nr++;
+			io_run_task_work();
+		}
 	}
 	io_ring_submit_unlock(ctx, issue_flags);
-done:
+	return cancel_all ? nr : ret;
+}
+
+static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_cancel_data cd = {
+		.ctx	= req->ctx,
+		.data	= req->cancel.addr,
+		.flags	= req->cancel.flags,
+	};
+	int ret;
+
+	ret = __io_async_cancel(&cd, req, issue_flags);
 	if (ret < 0)
 		req_set_fail(req);
 	io_req_complete_post(req, ret, 0);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 1845cf7c80ba..476e58a2837f 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -187,6 +187,13 @@ enum {
 #define IORING_POLL_UPDATE_EVENTS	(1U << 1)
 #define IORING_POLL_UPDATE_USER_DATA	(1U << 2)
 
+/*
+ * ASYNC_CANCEL flags.
+ *
+ * IORING_ASYNC_CANCEL_ALL	Cancel all requests that match the given key
+ */
+#define IORING_ASYNC_CANCEL_ALL	(1U << 0)
+
 /*
  * IO completion data structure (Completion Queue Entry)
  */
-- 
2.35.1