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 | */ |
23 | int 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 | } |
37 | EXPORT_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 | */ |
43 | void 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 | } |
52 | EXPORT_SYMBOL(scsi_dma_unmap); |
53 |