Currently, creating an io_uring with IORING_SETUP_IOPOLL requires all requests issued to it to support iopoll. This prevents, for example, using ublk zero-copy together with IORING_SETUP_IOPOLL, as ublk zero-copy buffer registrations are performed using a uring_cmd. There's no technical reason why these non-iopoll uring_cmds can't be supported. They will either complete synchronously or via an external mechanism that calls io_uring_cmd_done(), io_uring_cmd_post_mshot_cqe32(), or io_uring_mshot_cmd_post_cqe(), so they don't need to be polled. Allow uring_cmd requests to be issued to IORING_SETUP_IOPOLL io_urings even if their files don't implement ->uring_cmd_iopoll(). For these uring_cmd requests, skip initializing struct io_kiocb's iopoll fields, don't set REQ_F_IOPOLL, and don't set IO_URING_F_IOPOLL in issue_flags. Signed-off-by: Caleb Sander Mateos Reviewed-by: Kanchan Joshi Reviewed-by: Anuj Gupta --- io_uring/uring_cmd.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index b651c63f6e20..7b25dcd9d05f 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -255,13 +255,11 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags) issue_flags |= IO_URING_F_SQE128; if (ctx->flags & (IORING_SETUP_CQE32 | IORING_SETUP_CQE_MIXED)) issue_flags |= IO_URING_F_CQE32; if (io_is_compat(ctx)) issue_flags |= IO_URING_F_COMPAT; - if (ctx->flags & IORING_SETUP_IOPOLL) { - if (!file->f_op->uring_cmd_iopoll) - return -EOPNOTSUPP; + if (ctx->flags & IORING_SETUP_IOPOLL && file->f_op->uring_cmd_iopoll) { req->flags |= REQ_F_IOPOLL; issue_flags |= IO_URING_F_IOPOLL; req->iopoll_completed = 0; if (ctx->flags & IORING_SETUP_HYBRID_IOPOLL) { /* make sure every req only blocks once */ -- 2.45.2