nvme-ioctl: fix leaked requests on mapping error

All the callers assume nvme_map_user_request() frees the request on a
failure. This wasn't happening on invalid metadata or io_uring command
flags, so we've been leaking those requests.

Fixes: 23fd22e ("nvme: wire up fixed buffer support for nvme passthrough")
Fixes: 7c2fd76 ("nvme: fix metadata handling in nvme-passthrough")
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/ioctl.c

@@ -128,8 +128,10 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
 	if (!nvme_ctrl_sgl_supported(ctrl))
 		dev_warn_once(ctrl->device, "using unchecked data buffer\n");
 	if (has_metadata) {
-		if (!supports_metadata)
-			return -EINVAL;
+		if (!supports_metadata) {
+			ret = -EINVAL;
+			goto out;
+		}
 		if (!nvme_ctrl_meta_sgl_supported(ctrl))
 			dev_warn_once(ctrl->device,
 				      "using unchecked metadata buffer\n");
@@ -139,8 +141,10 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
 		struct iov_iter iter;
 
 		/* fixedbufs is only for non-vectored io */
-		if (WARN_ON_ONCE(flags & NVME_IOCTL_VEC))
-			return -EINVAL;
+		if (WARN_ON_ONCE(flags & NVME_IOCTL_VEC)) {
+			ret = -EINVAL;
+			goto out;
+		}
 		ret = io_uring_cmd_import_fixed(ubuffer, bufflen,
 				rq_data_dir(req), &iter, ioucmd);
 		if (ret < 0)