target/tcm_qla2xxx: Add/use target_reverse_dma_direction() in target_core_fabric.h

Reversing the dma_data_direction for pci_map_sg() friends is useful
for other drivers, so move it from tcm_qla2xxx into inline code
within target_core_fabric.h.

Also drop internal usage of equivlient in tcm_qla2xxx fabric code.

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Cc: Chad Dupuis <chad.dupuis@qlogic.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 192eb52684e9..882b650e32be 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -179,4 +179,30 @@ u32	iscsi_get_pr_transport_id_len(struct se_portal_group *, struct se_node_acl *
 char    *iscsi_parse_pr_out_transport_id(struct se_portal_group *, const char *,
                 u32 *, char **);
 
+/*
+ * The LIO target core uses DMA_TO_DEVICE to mean that data is going
+ * to the target (eg handling a WRITE) and DMA_FROM_DEVICE to mean
+ * that data is coming from the target (eg handling a READ).  However,
+ * this is just the opposite of what we have to tell the DMA mapping
+ * layer -- eg when handling a READ, the HBA will have to DMA the data
+ * out of memory so it can send it to the initiator, which means we
+ * need to use DMA_TO_DEVICE when we map the data.
+ */
+static inline enum dma_data_direction
+target_reverse_dma_direction(struct se_cmd *se_cmd)
+{
+        if (se_cmd->se_cmd_flags & SCF_BIDI)
+                return DMA_BIDIRECTIONAL;
+
+        switch (se_cmd->data_direction) {
+        case DMA_TO_DEVICE:
+                return DMA_FROM_DEVICE;
+        case DMA_FROM_DEVICE:
+                return DMA_TO_DEVICE;
+        case DMA_NONE:
+        default:
+                return DMA_NONE;
+        }
+}
+
 #endif /* TARGET_CORE_FABRICH */