1/*
2 * SCSI library functions depending on DMA
3 */
4
5#include <linux/blkdev.h>
6#include <linux/device.h>
7#include <linux/export.h>
8#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)) {
27		struct device *dev = cmd->device->host->dma_dev;
28
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)) {
45		struct device *dev = cmd->device->host->dma_dev;
46
47		dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
48			     cmd->sc_data_direction);
49	}
50}
51EXPORT_SYMBOL(scsi_dma_unmap);
52