]> git.kernelconcepts.de Git - karo-tx-linux.git/blob - drivers/scsi/scsi_lib_dma.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[karo-tx-linux.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/export.h>
8 #include <linux/kernel.h>
9
10 #include <scsi/scsi.h>
11 #include <scsi/scsi_cmnd.h>
12 #include <scsi/scsi_device.h>
13 #include <scsi/scsi_host.h>
14
15 /**
16  * scsi_dma_map - perform DMA mapping against command's sg lists
17  * @cmd:        scsi command
18  *
19  * Returns the number of sg lists actually used, zero if the sg lists
20  * is NULL, or -ENOMEM if the mapping failed.
21  */
22 int scsi_dma_map(struct scsi_cmnd *cmd)
23 {
24         int nseg = 0;
25
26         if (scsi_sg_count(cmd)) {
27                 struct device *dev = cmd->device->host->dma_dev;
28
29                 nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
30                                   cmd->sc_data_direction);
31                 if (unlikely(!nseg))
32                         return -ENOMEM;
33         }
34         return nseg;
35 }
36 EXPORT_SYMBOL(scsi_dma_map);
37
38 /**
39  * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
40  * @cmd:        scsi command
41  */
42 void scsi_dma_unmap(struct scsi_cmnd *cmd)
43 {
44         if (scsi_sg_count(cmd)) {
45                 struct device *dev = cmd->device->host->dma_dev;
46
47                 dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
48                              cmd->sc_data_direction);
49         }
50 }
51 EXPORT_SYMBOL(scsi_dma_unmap);