blob: dcd128583b89795c6294d79c2b61df6fdc0f3dd5 [file] [log] [blame]
Cornelia Huck7689e822007-07-09 11:59:59 -07001/*
2 * SCSI library functions depending on DMA
3 */
4
5#include <linux/blkdev.h>
6#include <linux/device.h>
7#include <linux/kernel.h>
8
9#include <scsi/scsi.h>
10#include <scsi/scsi_cmnd.h>
11#include <scsi/scsi_device.h>
12#include <scsi/scsi_host.h>
13
14/**
15 * scsi_dma_map - perform DMA mapping against command's sg lists
16 * @cmd: scsi command
17 *
18 * Returns the number of sg lists actually used, zero if the sg lists
19 * is NULL, or -ENOMEM if the mapping failed.
20 */
21int scsi_dma_map(struct scsi_cmnd *cmd)
22{
23 int nseg = 0;
24
25 if (scsi_sg_count(cmd)) {
James Bottomleyd139b9b2009-11-05 13:33:12 -060026 struct device *dev = cmd->device->host->dma_dev;
Cornelia Huck7689e822007-07-09 11:59:59 -070027
28 nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
29 cmd->sc_data_direction);
30 if (unlikely(!nseg))
31 return -ENOMEM;
32 }
33 return nseg;
34}
35EXPORT_SYMBOL(scsi_dma_map);
36
37/**
38 * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
39 * @cmd: scsi command
40 */
41void scsi_dma_unmap(struct scsi_cmnd *cmd)
42{
43 if (scsi_sg_count(cmd)) {
James Bottomleyd139b9b2009-11-05 13:33:12 -060044 struct device *dev = cmd->device->host->dma_dev;
Cornelia Huck7689e822007-07-09 11:59:59 -070045
46 dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
47 cmd->sc_data_direction);
48 }
49}
50EXPORT_SYMBOL(scsi_dma_unmap);