[PATCH] cciss: fix for DMA brokeness

The CCISS driver seems to loose track of DMA mappings created by it's
fill_cmd() routine.  Neither callers of this routine are extracting the DMA
address created in order to do the unmap.

Instead, they simply try to unmap 0x0.  It's easy to see this problem on an
x86_64 system when using the "swiotlb=force" boot option.  In this case, the
driver is leaking resources of the swiotlb and not causing a sync of the
bounce buffer.
Signed-off-by: NAlex Williamson <alex.williamson@hp.com>
Signed-off-by: NMike Miller <mike.miller@hp.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/block/cciss.c

@@ -1730,8 +1730,10 @@ case CMD_HARDWARE_ERR:
 		}
 	}	
 	/* unlock the buffers from DMA */
+	buff_dma_handle.val32.lower = c->SG[0].Addr.lower;
+	buff_dma_handle.val32.upper = c->SG[0].Addr.upper;
 	pci_unmap_single( h->pdev, (dma_addr_t) buff_dma_handle.val,
-			size, PCI_DMA_BIDIRECTIONAL);
+			c->SG[0].Len, PCI_DMA_BIDIRECTIONAL);
 	cmd_free(h, c, 0);
         return(return_status);
 
@@ -2011,8 +2013,10 @@ static int sendcmd(
 		
 cleanup1:	
 	/* unlock the data buffer from DMA */
+	buff_dma_handle.val32.lower = c->SG[0].Addr.lower;
+	buff_dma_handle.val32.upper = c->SG[0].Addr.upper;
 	pci_unmap_single(info_p->pdev, (dma_addr_t) buff_dma_handle.val,
-				size, PCI_DMA_BIDIRECTIONAL);
+				c->SG[0].Len, PCI_DMA_BIDIRECTIONAL);
 	cmd_free(info_p, c, 1);
 	return (status);
 }