diff options
| author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2007-05-26 14:04:03 +0900 |
|---|---|---|
| committer | James Bottomley <jejb@mulgrave.il.steeleye.com> | 2007-05-26 16:29:59 -0500 |
| commit | 824d7b570b4dec49e868c251d670941b02a1e489 (patch) | |
| tree | 1590c87323c9f9235945ba03627fd1ce0b731a1f /drivers | |
| parent | 9ef3e4a4527e1f65b8776287c6d4fd1fca5ba98f (diff) | |
[SCSI] scsi_lib: add scatter/gather data buffer accessors
This adds a set of accessors for the scsi data buffer. This is in
preparation for chaining sg lists and bidirectional requests (and
possibly, the mid-layer dma mapping).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 1f5a07bf2a7..70454b4e848 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2290,3 +2290,41 @@ void scsi_kunmap_atomic_sg(void *virt) kunmap_atomic(virt, KM_BIO_SRC_IRQ); } EXPORT_SYMBOL(scsi_kunmap_atomic_sg); + +/** + * scsi_dma_map - perform DMA mapping against command's sg lists + * @cmd: scsi command + * + * Returns the number of sg lists actually used, zero if the sg lists + * is NULL, or -ENOMEM if the mapping failed. + */ +int scsi_dma_map(struct scsi_cmnd *cmd) +{ + int nseg = 0; + + if (scsi_sg_count(cmd)) { + struct device *dev = cmd->device->host->shost_gendev.parent; + + nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd), + cmd->sc_data_direction); + if (unlikely(!nseg)) + return -ENOMEM; + } + return nseg; +} +EXPORT_SYMBOL(scsi_dma_map); + +/** + * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map + * @cmd: scsi command + */ +void scsi_dma_unmap(struct scsi_cmnd *cmd) +{ + if (scsi_sg_count(cmd)) { + struct device *dev = cmd->device->host->shost_gendev.parent; + + dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd), + cmd->sc_data_direction); + } +} +EXPORT_SYMBOL(scsi_dma_unmap); |