io_uring/cancel: support opcode based lookup and cancelation

Add IORING_ASYNC_CANCEL_OP flag for cancelation, which allows the
application to target cancelation based on the opcode of the original
request.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

include/uapi/linux/io_uring.h

@@ -300,12 +300,14 @@ enum io_uring_op {
  * IORING_ASYNC_CANCEL_ANY	Match any request
  * IORING_ASYNC_CANCEL_FD_FIXED	'fd' passed in is a fixed descriptor
  * IORING_ASYNC_CANCEL_USERDATA	Match on user_data, default for no other key
+ * IORING_ASYNC_CANCEL_OP	Match request based on opcode
  */
 #define IORING_ASYNC_CANCEL_ALL	(1U << 0)
 #define IORING_ASYNC_CANCEL_FD	(1U << 1)
 #define IORING_ASYNC_CANCEL_ANY	(1U << 2)
 #define IORING_ASYNC_CANCEL_FD_FIXED	(1U << 3)
 #define IORING_ASYNC_CANCEL_USERDATA	(1U << 4)
+#define IORING_ASYNC_CANCEL_OP	(1U << 5)
 
 /*
  * send/sendmsg and recv/recvmsg flags (sqe->ioprio)

io_uring/cancel.c

@@ -22,11 +22,12 @@ struct io_cancel {
 	u64				addr;
 	u32				flags;
 	s32				fd;
+	u8				opcode;
 };
 
 #define CANCEL_FLAGS	(IORING_ASYNC_CANCEL_ALL | IORING_ASYNC_CANCEL_FD | \
 			 IORING_ASYNC_CANCEL_ANY | IORING_ASYNC_CANCEL_FD_FIXED | \
-			 IORING_ASYNC_CANCEL_USERDATA)
+			 IORING_ASYNC_CANCEL_USERDATA | IORING_ASYNC_CANCEL_OP)
 
 /*
  * Returns true if the request matches the criteria outlined by 'cd'.
@@ -38,7 +39,7 @@ bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd)
 	if (req->ctx != cd->ctx)
 		return false;
 
-	if (!(cd->flags & (IORING_ASYNC_CANCEL_FD)))
+	if (!(cd->flags & (IORING_ASYNC_CANCEL_FD | IORING_ASYNC_CANCEL_OP)))
 		match_user_data = true;
 
 	if (cd->flags & IORING_ASYNC_CANCEL_ANY)
@@ -47,6 +48,10 @@ bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd)
 		if (req->file != cd->file)
 			return false;
 	}
+	if (cd->flags & IORING_ASYNC_CANCEL_OP) {
+		if (req->opcode != cd->opcode)
+			return false;
+	}
 	if (match_user_data && req->cqe.user_data != cd->data)
 		return false;
 	if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
@@ -127,7 +132,7 @@ int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	if (unlikely(req->flags & REQ_F_BUFFER_SELECT))
 		return -EINVAL;
-	if (sqe->off || sqe->len || sqe->splice_fd_in)
+	if (sqe->off || sqe->splice_fd_in)
 		return -EINVAL;
 
 	cancel->addr = READ_ONCE(sqe->addr);
@@ -139,6 +144,11 @@ int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 			return -EINVAL;
 		cancel->fd = READ_ONCE(sqe->fd);
 	}
+	if (cancel->flags & IORING_ASYNC_CANCEL_OP) {
+		if (cancel->flags & IORING_ASYNC_CANCEL_ANY)
+			return -EINVAL;
+		cancel->opcode = READ_ONCE(sqe->len);
+	}
 
 	return 0;
 }
@@ -185,6 +195,7 @@ int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 		.ctx	= req->ctx,
 		.data	= cancel->addr,
 		.flags	= cancel->flags,
+		.opcode	= cancel->opcode,
 		.seq	= atomic_inc_return(&req->ctx->cancel_seq),
 	};
 	struct io_uring_task *tctx = req->task->io_uring;

io_uring/cancel.h

@@ -8,11 +8,11 @@ struct io_cancel_data {
 		u64 data;
 		struct file *file;
 	};
+	u8 opcode;
 	u32 flags;
 	int seq;
 };
 
-
 int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags);
 

io_uring/poll.c

@@ -851,7 +851,8 @@ static int __io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
 	struct io_hash_bucket *bucket;
 	struct io_kiocb *req;
 
-	if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
+	if (cd->flags & (IORING_ASYNC_CANCEL_FD | IORING_ASYNC_CANCEL_OP |
+			 IORING_ASYNC_CANCEL_ANY))
 		req = io_poll_file_find(ctx, cd, table, &bucket);
 	else
 		req = io_poll_find(ctx, false, cd, table, &bucket);