[SCSI] QLOGICPTI: Do not unmap DMA unless we actually mapped something.

We only map DMA when cmd->request_bufflen is non-zero for non-sg
buffers, we thus should make the same check when unmapping.

Based upon a report from Pasi Pirhonen.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/scsi/qlogicpti.c b/drivers/scsi/qlogicpti.c
index 9b827ce..9f10689 100644 (file)
--- a/drivers/scsi/qlogicpti.c
+++ b/drivers/scsi/qlogicpti.c
@@ -1281,7 +1281,7 @@ static struct scsi_cmnd *qlogicpti_intr_handler(struct qlogicpti *qpti)
                                      (struct scatterlist *)Cmnd->request_buffer,
                                      Cmnd->use_sg,
                                      Cmnd->sc_data_direction);
-               } else {
+               } else if (Cmnd->request_bufflen) {
                        sbus_unmap_single(qpti->sdev,
                                          (__u32)((unsigned long)Cmnd->SCp.ptr),
                                          Cmnd->request_bufflen,