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drivers/scsi/scsi_lib_dma.c
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81f7e3824
Initial Release, ...
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// 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);
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