SCSI: implement sd_unlock_native_capacity()

Implement sd_unlock_native_capacity() method which calls into
hostt->unlock_native_capacity() if implemented.  This will be invoked
by block layer if partitions extend beyond the end of the device and
can be used to implement, for example, on-demand ATA host protected
area unlocking.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 30 insertions, 0 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 829cc37abc41..8802e48bc063 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -97,6 +97,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
 #endif
 
 static int  sd_revalidate_disk(struct gendisk *);
+static void sd_unlock_native_capacity(struct gendisk *disk);
 static int  sd_probe(struct device *);
 static int  sd_remove(struct device *);
 static void sd_shutdown(struct device *);
@@ -1101,6 +1102,7 @@ static const struct block_device_operations sd_fops = {
 #endif
         .media_changed          = sd_media_changed,
         .revalidate_disk        = sd_revalidate_disk,
+        .unlock_native_capacity = sd_unlock_native_capacity,
 };
 
 static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
@@ -2121,6 +2123,26 @@ static int sd_revalidate_disk(struct gendisk *disk)
 }
 
 /**
+ *      sd_unlock_native_capacity - unlock native capacity
+ *      @disk: struct gendisk to set capacity for
+ *
+ *      Block layer calls this function if it detects that partitions
+ *      on @disk reach beyond the end of the device.  If the SCSI host
+ *      implements ->unlock_native_capacity() method, it's invoked to
+ *      give it a chance to adjust the device capacity.
+ *
+ *      CONTEXT:
+ *      Defined by block layer.  Might sleep.
+ */
+static void sd_unlock_native_capacity(struct gendisk *disk)
+{
+        struct scsi_device *sdev = scsi_disk(disk)->device;
+
+        if (sdev->host->hostt->unlock_native_capacity)
+                sdev->host->hostt->unlock_native_capacity(sdev);
+}
+
+/**
  *      sd_format_disk_name - format disk name
  *      @prefix: name prefix - ie. "sd" for SCSI disks
  *      @index: index of the disk to format name for
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index c50a97fc76f9..b7bdecb7b76e 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -327,6 +327,14 @@ struct scsi_host_template {
                         sector_t, int []);
 
         /*
+         * This function is called when one or more partitions on the
+         * device reach beyond the end of the device.
+         *
+         * Status: OPTIONAL
+         */
+        void (*unlock_native_capacity)(struct scsi_device *);
+
+        /*
          * Can be used to export driver statistics and other infos to the
          * world outside the kernel ie. userspace and it also provides an
          * interface to feed the driver with information.