partitions: add ->set_capacity block device method

* Add ->set_capacity block device method and use it in rescan_partitions()
  to attempt enabling native capacity of the device upon detecting the
  partition which exceeds device capacity.

* Add GENHD_FL_NATIVE_CAPACITY flag to try limit attempts of enabling
  native capacity during partition scan.

Together with the consecutive patch implementing ->set_capacity method in
ide-gd device driver this allows automatic disabling of Host Protected Area
(HPA) if any partitions overlapping HPA are detected.

Cc: Robert Hancock <hancockrwd@gmail.com>
Cc: Frans Pop <elendil@planet.nl>
Cc: "Andries E. Brouwer" <Andries.Brouwer@cwi.nl>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Emphatically-Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

2 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6f841fb1be30..a2d7298be351 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1106,6 +1106,8 @@ struct block_device_operations {
         int (*direct_access) (struct block_device *, sector_t,
                                                 void **, unsigned long *);
         int (*media_changed) (struct gendisk *);
+        unsigned long long (*set_capacity) (struct gendisk *,
+                                                unsigned long long);
         int (*revalidate_disk) (struct gendisk *);
         int (*getgeo)(struct block_device *, struct hd_geometry *);
         struct module *owner;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 634c53028fb8..239e24b081a9 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -113,6 +113,7 @@ struct hd_struct {
 #define GENHD_FL_UP                             16
 #define GENHD_FL_SUPPRESS_PARTITION_INFO        32
 #define GENHD_FL_EXT_DEVT                       64 /* allow extended devt */
+#define GENHD_FL_NATIVE_CAPACITY                128
 
 #define BLK_SCSI_MAX_CMDS       (256)
 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))