[libata] allow ATAPI to be enabled with new atapi_enabled module option

ATAPI is getting close to being ready.  To increase exposure, we enable
the code in the upstream kernel, but default it to off (present
behavior).  Users must pass atapi_enabled=1 as a module option (if
module) or on the kernel command line (if built in) to turn on
discovery of their ATAPI devices.

3 files changed, 9 insertions, 4 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index dee4b12b034..d824938d05c 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -75,6 +75,10 @@ static void __ata_qc_complete(struct ata_queued_cmd *qc);
 static unsigned int ata_unique_id = 1;
 static struct workqueue_struct *ata_wq;
 
+int atapi_enabled = 0;
+module_param(atapi_enabled, int, 0444);
+MODULE_PARM_DESC(atapi_enabled, "Enable discovery of ATAPI devices (0=off, 1=on)");
+
 MODULE_AUTHOR("Jeff Garzik");
 MODULE_DESCRIPTION("Library module for ATA devices");
 MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 346eb36b1e3..55823765425 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -1470,10 +1470,10 @@ ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev)
         if (unlikely(!ata_dev_present(dev)))
                 return NULL;
 
-#ifndef ATA_ENABLE_ATAPI
-        if (unlikely(dev->class == ATA_DEV_ATAPI))
-                return NULL;
-#endif
+        if (atapi_enabled) {
+                if (unlikely(dev->class == ATA_DEV_ATAPI))
+                        return NULL;
+        }
 
         return dev;
 }
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index 809c634afbc..d608b3a0f6f 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -38,6 +38,7 @@ struct ata_scsi_args {
 };
 
 /* libata-core.c */
+extern int atapi_enabled;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
                                       struct ata_device *dev);
 extern void ata_qc_free(struct ata_queued_cmd *qc);