1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SCSI library functions depending on DMA
4 */
5
6#include <linux/blkdev.h>
7#include <linux/device.h>
8#include <linux/export.h>
9#include <linux/kernel.h>
10
11#include <scsi/scsi.h>
12#include <scsi/scsi_cmnd.h>
13#include <scsi/scsi_device.h>
14#include <scsi/scsi_host.h>
15
16/**
17 * scsi_dma_map - perform DMA mapping against command's sg lists
18 * @cmd: scsi command
19 *
20 * Returns the number of sg lists actually used, zero if the sg lists
21 * is NULL, or -ENOMEM if the mapping failed.
22 */
23int scsi_dma_map(struct scsi_cmnd *cmd)
24{
25 int nseg = 0;
26
27 if (scsi_sg_count(cmd)) {
28 struct device *dev = cmd->device->host->dma_dev;
29
30 nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
31 cmd->sc_data_direction);
32 if (unlikely(!nseg))
33 return -ENOMEM;
34 }
35 return nseg;
36}
37EXPORT_SYMBOL(scsi_dma_map);
38
39/**
40 * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
41 * @cmd: scsi command
42 */
43void scsi_dma_unmap(struct scsi_cmnd *cmd)
44{
45 if (scsi_sg_count(cmd)) {
46 struct device *dev = cmd->device->host->dma_dev;
47
48 dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
49 cmd->sc_data_direction);
50 }
51}
52EXPORT_SYMBOL(scsi_dma_unmap);
53