Add 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@xxxxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 26 ++++++++++++++++++++++++++
include/scsi/scsi_cmnd.h | 11 +++++++++++
2 files changed, 37 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1f5a07b..a2ebe61 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2290,3 +2290,29 @@ void scsi_kunmap_atomic_sg(void *virt)
kunmap_atomic(virt, KM_BIO_SRC_IRQ);
}
EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
+
+int scsi_dma_map(struct device *dev, struct scsi_cmnd *cmd)
+{
+ int nseg = 0;
+
+ if (cmd->use_sg) {
+ struct scatterlist *sg =
+ (struct scatterlist *) cmd->request_buffer;
+
+ nseg = dma_map_sg(dev, sg, cmd->use_sg, cmd->sc_data_direction);
+ if (unlikely(!nseg))
+ return -ENOMEM;
+ }
+ return nseg;
+}
+EXPORT_SYMBOL(scsi_dma_map);
+
+void scsi_dma_unmap(struct device *dev, struct scsi_cmnd *cmd)
+{
+ if (cmd->use_sg) {
+ struct scatterlist *sg =
+ (struct scatterlist *) cmd->request_buffer;
+ dma_unmap_sg(dev, sg, cmd->use_sg, cmd->sc_data_direction);
+ }
+}
+EXPORT_SYMBOL(scsi_dma_unmap);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index a2e0c10..5f5a179 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -135,4 +135,15 @@ extern void scsi_kunmap_atomic_sg(void *
extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
extern void scsi_free_sgtable(struct scatterlist *, int);
+extern int scsi_dma_map(struct device *dev, struct scsi_cmnd *cmd);
+extern void scsi_dma_unmap(struct device *dev, struct scsi_cmnd *cmd);
+
+#define scsi_sg_count(cmd) ((cmd)->use_sg)
+#define scsi_sglist(cmd) ((struct scatterlist *)(cmd)->request_buffer)
+#define scsi_bufflen(cmd) ((cmd)->request_bufflen)
+#define scsi_resid(cmd) ((cmd)->resid)
+
+#define scsi_for_each_sg(cmd, sg, nseg, __i) \
+ for (__i = 0, sg = scsi_sglist(cmd); __i < (nseg); __i++, (sg)++)
+
#endif /* _SCSI_SCSI_CMND_H */
--
1.4.3.2
-
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