io_uring/cmd: Pass compat mode in issue_flags

Create a new flag to track if the operation is running compat mode.
This basically check the context->compat and pass it to the issue_flags,
so, it could be queried later in the callbacks.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20231016134750.1381153-6-leitao@debian.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

include/linux/io_uring.h

@@ -23,6 +23,7 @@ enum io_uring_cmd_flags {
 
 	/* set when uring wants to cancel a previously issued command */
 	IO_URING_F_CANCEL		= (1 << 11),
+	IO_URING_F_COMPAT		= (1 << 12),
 };
 
 /* only top 8 bits of sqe->uring_cmd_flags for kernel internal use */

io_uring/uring_cmd.c

@@ -175,6 +175,8 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
 		issue_flags |= IO_URING_F_SQE128;
 	if (ctx->flags & IORING_SETUP_CQE32)
 		issue_flags |= IO_URING_F_CQE32;
+	if (ctx->compat)
+		issue_flags |= IO_URING_F_COMPAT;
 	if (ctx->flags & IORING_SETUP_IOPOLL) {
 		if (!file->f_op->uring_cmd_iopoll)
 			return -EOPNOTSUPP;