io_uring: remove uring_cmd cookie

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Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20231130215309.2923568-5-kbusch@meta.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

include/linux/io_uring.h

@@ -32,12 +32,8 @@ enum io_uring_cmd_flags {
 struct io_uring_cmd {
 	struct file	*file;
 	const struct io_uring_sqe *sqe;
-	union {
-		/* callback to defer completions to task context */
-		void (*task_work_cb)(struct io_uring_cmd *cmd, unsigned);
-		/* used for polled completion */
-		void *cookie;
-	};
+	/* callback to defer completions to task context */
+	void (*task_work_cb)(struct io_uring_cmd *cmd, unsigned);
 	u32		cmd_op;
 	u32		flags;
 	u8		pdu[32]; /* available inline for free use */

io_uring/uring_cmd.c

@@ -182,7 +182,6 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
 			return -EOPNOTSUPP;
 		issue_flags |= IO_URING_F_IOPOLL;
 		req->iopoll_completed = 0;
-		WRITE_ONCE(ioucmd->cookie, NULL);
 	}
 
 	ret = file->f_op->uring_cmd(ioucmd, issue_flags);