53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* SCSI library functions depending on DMA
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*/
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#include <linux/blkdev.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_host.h>
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/**
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* scsi_dma_map - perform DMA mapping against command's sg lists
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* @cmd: scsi command
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*
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* Returns the number of sg lists actually used, zero if the sg lists
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* is NULL, or -ENOMEM if the mapping failed.
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*/
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int scsi_dma_map(struct scsi_cmnd *cmd)
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{
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int nseg = 0;
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if (scsi_sg_count(cmd)) {
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struct device *dev = cmd->device->host->dma_dev;
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nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
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cmd->sc_data_direction);
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if (unlikely(!nseg))
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return -ENOMEM;
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}
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return nseg;
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}
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EXPORT_SYMBOL(scsi_dma_map);
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/**
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* scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
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* @cmd: scsi command
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*/
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void scsi_dma_unmap(struct scsi_cmnd *cmd)
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{
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if (scsi_sg_count(cmd)) {
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struct device *dev = cmd->device->host->dma_dev;
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dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
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cmd->sc_data_direction);
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}
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}
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EXPORT_SYMBOL(scsi_dma_unmap);
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