[SCSI] bnx2fc: Broadcom FCoE offload driver
[linux-2.6.git] / drivers / scsi / scsi_lib_dma.c
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->dma_dev;
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->dma_dev;
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);