1 /* 2 * SCSI library functions depending on DMA 3 */ 4 5 #include <linux/blkdev.h> 6 #include <linux/device.h> 7 #include <linux/kernel.h> 8 9 #include <scsi/scsi.h> 10 #include <scsi/scsi_cmnd.h> 11 #include <scsi/scsi_device.h> 12 #include <scsi/scsi_host.h> 13 14 /** 15 * scsi_dma_map - perform DMA mapping against command's sg lists 16 * @cmd: scsi command 17 * 18 * Returns the number of sg lists actually used, zero if the sg lists 19 * is NULL, or -ENOMEM if the mapping failed. 20 */ 21 int scsi_dma_map(struct scsi_cmnd *cmd) 22 { 23 int nseg = 0; 24 25 if (scsi_sg_count(cmd)) { 26 struct device *dev = cmd->device->host->shost_gendev.parent; 27 28 nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd), 29 cmd->sc_data_direction); 30 if (unlikely(!nseg)) 31 return -ENOMEM; 32 } 33 return nseg; 34 } 35 EXPORT_SYMBOL(scsi_dma_map); 36 37 /** 38 * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map 39 * @cmd: scsi command 40 */ 41 void scsi_dma_unmap(struct scsi_cmnd *cmd) 42 { 43 if (scsi_sg_count(cmd)) { 44 struct device *dev = cmd->device->host->shost_gendev.parent; 45 46 dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd), 47 cmd->sc_data_direction); 48 } 49 } 50 EXPORT_SYMBOL(scsi_dma_unmap); 51