blob: 2ac3f3975f785f86843bcade103446ddc28d722a [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>
Paul Gortmaker09703662011-05-27 09:37:25 -04007#include <linux/export.h>
Cornelia Huck7689e822007-07-09 11:59:59 -07008#include <linux/kernel.h>
9
10#include <scsi/scsi.h>
11#include <scsi/scsi_cmnd.h>
12#include <scsi/scsi_device.h>
13#include <scsi/scsi_host.h>
14
15/**
16 * scsi_dma_map - perform DMA mapping against command's sg lists
17 * @cmd: scsi command
18 *
19 * Returns the number of sg lists actually used, zero if the sg lists
20 * is NULL, or -ENOMEM if the mapping failed.
21 */
22int scsi_dma_map(struct scsi_cmnd *cmd)
23{
24 int nseg = 0;
25
26 if (scsi_sg_count(cmd)) {
James Bottomleyd139b9b2009-11-05 13:33:12 -060027 struct device *dev = cmd->device->host->dma_dev;
Cornelia Huck7689e822007-07-09 11:59:59 -070028
29 nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
30 cmd->sc_data_direction);
31 if (unlikely(!nseg))
32 return -ENOMEM;
33 }
34 return nseg;
35}
36EXPORT_SYMBOL(scsi_dma_map);
37
38/**
39 * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
40 * @cmd: scsi command
41 */
42void scsi_dma_unmap(struct scsi_cmnd *cmd)
43{
44 if (scsi_sg_count(cmd)) {
James Bottomleyd139b9b2009-11-05 13:33:12 -060045 struct device *dev = cmd->device->host->dma_dev;
Cornelia Huck7689e822007-07-09 11:59:59 -070046
47 dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
48 cmd->sc_data_direction);
49 }
50}
51EXPORT_SYMBOL(scsi_dma_unmap);