[PATCH 2/4] SCSI: implement sd_set_capacity()

[Tejun Heo <tj@kernel.org>]

Implement sd_set_capacity() method which calls into
hostt->set_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>
---
 drivers/scsi/sd.c        |   26 ++++++++++++++++++++++++++
 include/scsi/scsi_host.h |   11 +++++++++++
 2 files changed, 37 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8b827f3..59d5e8f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -97,6 +97,8 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
 #endif
 
 static int  sd_revalidate_disk(struct gendisk *);
+static unsigned long long sd_set_capacity(struct gendisk *disk,
+					  unsigned long long new_capacity);
 static int  sd_probe(struct device *);
 static int  sd_remove(struct device *);
 static void sd_shutdown(struct device *);
@@ -1100,6 +1102,7 @@ static const struct block_device_operations sd_fops = {
 #endif
 	.media_changed		= sd_media_changed,
 	.revalidate_disk	= sd_revalidate_disk,
+	.set_capacity		= sd_set_capacity,
 };
 
 static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
@@ -2101,6 +2104,29 @@ static int sd_revalidate_disk(struct gendisk *disk)
 }
 
 /**
+ *	sd_set_capacity - set disk capacity
+ *	@disk: struct gendisk to set capacity for
+ *	@new_capacity: new target capacity
+ *
+ *	Block layer calls this function if it detects that partitions
+ *	on @disk reach beyond the end of the device.  If the SCSI host
+ *	implements set_capacity method, it's invoked to give it a
+ *	chance to adjust the device capacity.
+ *
+ *	CONTEXT:
+ *	Defined by block layer.  Might sleep.
+ */
+static unsigned long long sd_set_capacity(struct gendisk *disk,
+					  unsigned long long new_capacity)
+{
+	struct scsi_device *sdev = scsi_disk(disk)->device;
+
+	if (sdev->host->hostt->set_capacity)
+		return sdev->host->hostt->set_capacity(sdev, new_capacity);
+	return 0;
+}
+
+/**
  *	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 c50a97f..31dba89 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -327,6 +327,17 @@ 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.  This function
+	 * should return the new capacity if disk was successfully
+	 * enlarged.  Return values smaller than the current capacity
+	 * are ignored.
+	 *
+	 * Status: OPTIONAL
+	 */
+	sector_t (*set_capacity)(struct scsi_device *, sector_t);
+
+	/*
 	 * 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.
-- 
1.6.4.2