| 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 |