[SCSI] scsi_lib_dma: fix bug with dma maps on nested scsi objects

Some of our virtual SCSI hosts don't have a proper bus parent at the
top, which can be a problem for doing DMA on them

This patch makes the host device cache a pointer to the physical bus
device and provides an extra API for setting it (the normal API picks
it up from the parent).  This patch also modifies the qla2xxx and lpfc
vport logic to use the new DMA host setting API.

Acked-By: James Smart  <james.smart@emulex.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5fd2da494d08..28a753d796f3 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -180,14 +180,20 @@ void scsi_remove_host(struct Scsi_Host *shost)
 EXPORT_SYMBOL(scsi_remove_host);
 
 /**
- * scsi_add_host - add a scsi host
+ * scsi_add_host_with_dma - add a scsi host with dma device
  * @shost:      scsi host pointer to add
  * @dev:        a struct device of type scsi class
+ * @dma_dev:    dma device for the host
+ *
+ * Note: You rarely need to worry about this unless you're in a
+ * virtualised host environments, so use the simpler scsi_add_host()
+ * function instead.
  *
  * Return value: 
  *      0 on success / != 0 for error
  **/
-int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
+int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
+                           struct device *dma_dev)
 {
         struct scsi_host_template *sht = shost->hostt;
         int error = -EINVAL;
@@ -207,6 +213,7 @@ int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 
         if (!shost->shost_gendev.parent)
                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
+        shost->dma_dev = dma_dev;
 
         error = device_add(&shost->shost_gendev);
         if (error)
@@ -262,7 +269,7 @@ int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
  fail:
         return error;
 }
-EXPORT_SYMBOL(scsi_add_host);
+EXPORT_SYMBOL(scsi_add_host_with_dma);
 
 static void scsi_host_dev_release(struct device *dev)
 {