LXR linux/drivers/scsi/scsi_lib

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