Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
                        return SCSI_MLQUEUE_DEVICE_BUSY;
        }
 
+       nseg = scsi_dma_map(cmd);
+       if (nseg < 0)
+               return SCSI_MLQUEUE_HOST_BUSY;
+
        /*
         * Get an scb to use.
         */
        scb = ahc_get_scb(ahc);
-       if (!scb)
+       if (!scb) {
+               scsi_dma_unmap(cmd);
                return SCSI_MLQUEUE_HOST_BUSY;
+       }
 
        scb->io_ctx = cmd;
        scb->platform_data->dev = dev;
        ahc_set_sense_residual(scb, 0);
        scb->sg_count = 0;
 
-       nseg = scsi_dma_map(cmd);
-       BUG_ON(nseg < 0);
        if (nseg > 0) {
                struct  ahc_dma_seg *sg;
                struct  scatterlist *cur_seg;