diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/scsi/scsi_lib_dma.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_lib_dma.c b/drivers/scsi/scsi_lib_dma.c new file mode 100644 index 000000000..572391527 --- /dev/null +++ b/drivers/scsi/scsi_lib_dma.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SCSI library functions depending on DMA + */ + +#include <linux/blkdev.h> +#include <linux/device.h> +#include <linux/export.h> +#include <linux/kernel.h> + +#include <scsi/scsi.h> +#include <scsi/scsi_cmnd.h> +#include <scsi/scsi_device.h> +#include <scsi/scsi_host.h> + +/** + * scsi_dma_map - perform DMA mapping against command's sg lists + * @cmd: scsi command + * + * Returns the number of sg lists actually used, zero if the sg lists + * is NULL, or -ENOMEM if the mapping failed. + */ +int scsi_dma_map(struct scsi_cmnd *cmd) +{ + int nseg = 0; + + if (scsi_sg_count(cmd)) { + struct device *dev = cmd->device->host->dma_dev; + + nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd), + cmd->sc_data_direction); + if (unlikely(!nseg)) + return -ENOMEM; + } + return nseg; +} +EXPORT_SYMBOL(scsi_dma_map); + +/** + * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map + * @cmd: scsi command + */ +void scsi_dma_unmap(struct scsi_cmnd *cmd) +{ + if (scsi_sg_count(cmd)) { + struct device *dev = cmd->device->host->dma_dev; + + dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd), + cmd->sc_data_direction); + } +} +EXPORT_SYMBOL(scsi_dma_unmap); |