If it is more cleaner bellow?

static int mucse_fw_send_cmd_wait(struct mucse_hw *hw,
                                  struct mbx_fw_cmd_req *req,
                                  struct mbx_fw_cmd_reply *reply)
{
        int len = le16_to_cpu(req->datalen) + MBX_REQ_HDR_LEN;
        int retry_cnt = 3;
        int err;

        err = mutex_lock_interruptible(&hw->mbx.lock);
        if (err)
                return err;
        err = hw->mbx.ops->write_posted(hw, (u32 *)req,
                                        L_WD(len));
        if (err)
                goto quit;
        do {
                err = hw->mbx.ops->read_posted(hw, (u32 *)reply,
                                               L_WD(sizeof(*reply)));
                if (err)
                        goto quit;
        } while (--retry_cnt >= 0 && reply->opcode != req->opcode);

        mutex_unlock(&hw->mbx.lock);
        if (retry_cnt < 0)
                return -ETIMEDOUT;
        if (reply->error_code)
                return -EIO;
        return 0;
quit:
        mutex_unlock(&hw->mbx.lock);
        return err;
}

You might want a read a few other drivers in mailine. Look at the
naming. I doubt you will find many using "quit" for a label. "out" or
"unlock" is more popular.

When it comes to locks, it is better to have one lock statement and
one unlock statement. It then becomes easy to see all paths lead to
the unlock.

	Andrew