nvme: enable vectored registered bufs for passthrough cmds

nvme already supports registered buffers for non-vectored io_uring
passthrough commands, enable it for the vectored mode as well. It takes
an iovec, each entry of which should contain a range within the same
registered buffer specificied in sqe->buf_index.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Author: isilence

drivers/nvme/host/ioctl.c

@@ -493,13 +493,15 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 	d.timeout_ms = READ_ONCE(cmd->timeout_ms);
 
 	if (d.data_len && (ioucmd->flags & IORING_URING_CMD_FIXED)) {
-		/* fixedbufs is only for non-vectored io */
-		if (vec)
-			return -EINVAL;
+		int ddir = nvme_is_write(&c) ? WRITE : READ;
 
-		ret = io_uring_cmd_import_fixed(d.addr, d.data_len,
-			nvme_is_write(&c) ? WRITE : READ, &iter, ioucmd,
-			issue_flags);
+		if (vec)
+			ret = io_uring_cmd_import_fixed_vec(ioucmd,
+					u64_to_user_ptr(d.addr), d.data_len,
+					ddir, &iter, issue_flags);
+		else
+			ret = io_uring_cmd_import_fixed(d.addr, d.data_len,
+					ddir, &iter, ioucmd, issue_flags);
 		if (ret < 0)
 			return ret;