[SCSI] libsas, aic94xx: fix dma mapping cockups with ATA

This one was noticed by Gilbert Wu of Adaptec:

The libata core actually does the DMA mapping for you, so there has to
be an exception in the device drivers that *don't* do dma mapping for
ATA commands.  However, since we've already done this, libsas must now
dma map any ATA commands that it wishes to issue ... and yes, this is a
horrible mess.

Additionally, the test in aic94xx for ATA protocols isn't quite right.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

3 files changed, 21 insertions, 3 deletions

diff --git a/drivers/scsi/aic94xx/aic94xx_task.c b/drivers/scsi/aic94xx/aic94xx_task.c
index 6c12c0f19f39..d5d8caba3560 100644
--- a/drivers/scsi/aic94xx/aic94xx_task.c
+++ b/drivers/scsi/aic94xx/aic94xx_task.c
@@ -76,7 +76,7 @@ static inline int asd_map_scatterlist(struct sas_task *task,
 
         /* STP tasks come from libata which has already mapped
          * the SG list */
-        if (task->task_proto == SAS_PROTOCOL_STP)
+        if (sas_protocol_ata(task->task_proto))
                 num_sg = task->num_scatter;
         else
                 num_sg = pci_map_sg(asd_ha->pcidev, task->scatter,
@@ -125,7 +125,7 @@ static inline int asd_map_scatterlist(struct sas_task *task,
 
         return 0;
 err_unmap:
-        if (task->task_proto != SAS_PROTOCOL_STP)
+        if (sas_protocol_ata(task->task_proto))
                 pci_unmap_sg(asd_ha->pcidev, task->scatter, task->num_scatter,
                              task->data_dir);
         return res;
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index a18c0f6d6668..4d768db1b567 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -110,6 +110,13 @@ static int sas_execute_task(struct sas_task *task, void *buffer, int size,
         task->total_xfer_len = size;
         task->data_dir = pci_dma_dir;
         task->task_done = sas_disc_task_done;
+        if (pci_dma_dir != PCI_DMA_NONE &&
+            sas_protocol_ata(task->task_proto)) {
+                task->num_scatter = pci_map_sg(task->dev->port->ha->pcidev,
+                                               task->scatter,
+                                               task->num_scatter,
+                                               task->data_dir);
+        }
 
         for (retries = 0; retries < 5; retries++) {
                 task->task_state_flags = SAS_TASK_STATE_PENDING;
@@ -192,8 +199,13 @@ static int sas_execute_task(struct sas_task *task, void *buffer, int size,
                 }
         }
 ex_err:
-        if (pci_dma_dir != PCI_DMA_NONE)
+        if (pci_dma_dir != PCI_DMA_NONE) {
+                if (sas_protocol_ata(task->task_proto))
+                        pci_unmap_sg(task->dev->port->ha->pcidev,
+                                     task->scatter, task->num_scatter,
+                                     task->data_dir);
                 kfree(scatter);
+        }
 out:
         return res;
 }
diff --git a/include/scsi/scsi_transport_sas.h b/include/scsi/scsi_transport_sas.h
index 9aedc19820b0..97eeb5b59ea5 100644
--- a/include/scsi/scsi_transport_sas.h
+++ b/include/scsi/scsi_transport_sas.h
@@ -23,6 +23,12 @@ enum sas_protocol {
         SAS_PROTOCOL_SSP                = 0x08,
 };
 
+static inline int sas_protocol_ata(enum sas_protocol proto)
+{
+        return ((proto & SAS_PROTOCOL_SATA) ||
+                (proto & SAS_PROTOCOL_STP))? 1 : 0;
+}
+
 enum sas_linkrate {
         /* These Values are defined in the SAS standard */
         SAS_LINK_RATE_UNKNOWN = 0,