ide-gd: implement block device ->set_capacity method (v2)

* Use ->probed_capacity to store native device capacity for ATA disks.

* Add ->set_capacity method to struct ide_disk_ops.

* Implement disk device ->set_capacity method for ATA disks.

* Implement block device ->set_capacity method.

v2:
* Check if LBA and HPA are supported in ide_disk_set_capacity().

* According to the spec the SET MAX ADDRESS command shall be
  immediately preceded by a READ NATIVE MAX ADDRESS command.

* Add ide_disk_hpa_{get_native,set}_capacity() helpers.

Together with the previous patch adding ->set_capacity block device
method 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>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Emphatically-Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-disk.c

@@ -302,14 +302,12 @@ static const struct drive_list_entry hpa_list[] = {
 	{ NULL,		NULL }
 };
 
-static void idedisk_check_hpa(ide_drive_t *drive)
+static u64 ide_disk_hpa_get_native_capacity(ide_drive_t *drive, int lba48)
 {
-	unsigned long long capacity, set_max;
-	int lba48 = ata_id_lba48_enabled(drive->id);
+	u64 capacity, set_max;
 
 	capacity = drive->capacity64;
-
-	set_max = idedisk_read_native_max_address(drive, lba48);
+	set_max  = idedisk_read_native_max_address(drive, lba48);
 
 	if (ide_in_drive_list(drive->id, hpa_list)) {
 		/*
@@ -320,23 +318,42 @@ static void idedisk_check_hpa(ide_drive_t *drive)
 			set_max--;
 	}
 
+	return set_max;
+}
+
+static u64 ide_disk_hpa_set_capacity(ide_drive_t *drive, u64 set_max, int lba48)
+{
+	set_max = idedisk_set_max_address(drive, set_max, lba48);
+	if (set_max)
+		drive->capacity64 = set_max;
+
+	return set_max;
+}
+
+static void idedisk_check_hpa(ide_drive_t *drive)
+{
+	u64 capacity, set_max;
+	int lba48 = ata_id_lba48_enabled(drive->id);
+
+	capacity = drive->capacity64;
+	set_max  = ide_disk_hpa_get_native_capacity(drive, lba48);
+
 	if (set_max <= capacity)
 		return;
 
+	drive->probed_capacity = set_max;
+
 	printk(KERN_INFO "%s: Host Protected Area detected.\n"
 			 "\tcurrent capacity is %llu sectors (%llu MB)\n"
 			 "\tnative  capacity is %llu sectors (%llu MB)\n",
 			 drive->name,
 			 capacity, sectors_to_MB(capacity),
 			 set_max, sectors_to_MB(set_max));
 
-	set_max = idedisk_set_max_address(drive, set_max, lba48);
-
-	if (set_max) {
-		drive->capacity64 = set_max;
+	set_max = ide_disk_hpa_set_capacity(drive, set_max, lba48);
+	if (set_max)
 		printk(KERN_INFO "%s: Host Protected Area disabled.\n",
 				 drive->name);
-	}
 }
 
 static int ide_disk_get_capacity(ide_drive_t *drive)
@@ -358,6 +375,8 @@ static int ide_disk_get_capacity(ide_drive_t *drive)
 		drive->capacity64 = drive->cyl * drive->head * drive->sect;
 	}
 
+	drive->probed_capacity = drive->capacity64;
+
 	if (lba) {
 		drive->dev_flags |= IDE_DFLAG_LBA;
 
@@ -376,7 +395,7 @@ static int ide_disk_get_capacity(ide_drive_t *drive)
 		       "%llu sectors (%llu MB)\n",
 		       drive->name, (unsigned long long)drive->capacity64,
 		       sectors_to_MB(drive->capacity64));
-		drive->capacity64 = 1ULL << 28;
+		drive->probed_capacity = drive->capacity64 = 1ULL << 28;
 	}
 
 	if ((drive->hwif->host_flags & IDE_HFLAG_NO_LBA48_DMA) &&
@@ -392,6 +411,31 @@ static int ide_disk_get_capacity(ide_drive_t *drive)
 	return 0;
 }
 
+static u64 ide_disk_set_capacity(ide_drive_t *drive, u64 capacity)
+{
+	u64 set = min(capacity, drive->probed_capacity);
+	u16 *id = drive->id;
+	int lba48 = ata_id_lba48_enabled(id);
+
+	if ((drive->dev_flags & IDE_DFLAG_LBA) == 0 ||
+	    ata_id_hpa_enabled(id) == 0)
+		goto out;
+
+	/*
+	 * according to the spec the SET MAX ADDRESS command shall be
+	 * immediately preceded by a READ NATIVE MAX ADDRESS command
+	 */
+	capacity = ide_disk_hpa_get_native_capacity(drive, lba48);
+	if (capacity == 0)
+		goto out;
+
+	set = ide_disk_hpa_set_capacity(drive, set, lba48);
+	if (set)
+		return set;
+out:
+	return drive->capacity64;
+}
+
 static void idedisk_prepare_flush(struct request_queue *q, struct request *rq)
 {
 	ide_drive_t *drive = q->queuedata;
@@ -741,6 +785,7 @@ static int ide_disk_set_doorlock(ide_drive_t *drive, struct gendisk *disk,
 
 const struct ide_disk_ops ide_ata_disk_ops = {
 	.check		= ide_disk_check,
+	.set_capacity	= ide_disk_set_capacity,
 	.get_capacity	= ide_disk_get_capacity,
 	.setup		= ide_disk_setup,
 	.flush		= ide_disk_flush,

drivers/ide/ide-gd.c

@@ -287,6 +287,19 @@ static int ide_gd_media_changed(struct gendisk *disk)
 	return ret;
 }
 
+static unsigned long long ide_gd_set_capacity(struct gendisk *disk,
+					      unsigned long long capacity)
+{
+	struct ide_disk_obj *idkp = ide_drv_g(disk, ide_disk_obj);
+	ide_drive_t *drive = idkp->drive;
+	const struct ide_disk_ops *disk_ops = drive->disk_ops;
+
+	if (disk_ops->set_capacity)
+		return disk_ops->set_capacity(drive, capacity);
+
+	return drive->capacity64;
+}
+
 static int ide_gd_revalidate_disk(struct gendisk *disk)
 {
 	struct ide_disk_obj *idkp = ide_drv_g(disk, ide_disk_obj);
@@ -315,6 +328,7 @@ static struct block_device_operations ide_gd_ops = {
 	.locked_ioctl		= ide_gd_ioctl,
 	.getgeo			= ide_gd_getgeo,
 	.media_changed		= ide_gd_media_changed,
+	.set_capacity		= ide_gd_set_capacity,
 	.revalidate_disk	= ide_gd_revalidate_disk
 };
 

include/linux/ide.h

@@ -397,6 +397,7 @@ struct ide_drive_s;
 struct ide_disk_ops {
 	int		(*check)(struct ide_drive_s *, const char *);
 	int		(*get_capacity)(struct ide_drive_s *);
+	u64		(*set_capacity)(struct ide_drive_s *, u64);
 	void		(*setup)(struct ide_drive_s *);
 	void		(*flush)(struct ide_drive_s *);
 	int		(*init_media)(struct ide_drive_s *, struct gendisk *);
@@ -568,8 +569,7 @@ struct ide_drive_s {
 	unsigned int	drive_data;	/* used by set_pio_mode/dev_select() */
 	unsigned int	failures;	/* current failure count */
 	unsigned int	max_failures;	/* maximum allowed failure count */
-	u64		probed_capacity;/* initial reported media capacity (ide-cd only currently) */
-
+	u64		probed_capacity;/* initial/native media capacity */
 	u64		capacity64;	/* total number of sectors */
 
 	int		lun;		/* logical unit */