[SCSI] sd: Logical Block Provisioning update

SBC3r26 contains many changes to the Logical Block Provisioning
interfaces (formerly known as Thin Provisioning ditto). This patch
implements support for both the old and new schemes using the same
heuristic as before (whether the LBP VPD page is present).

The new code also allows the provisioning mode (i.e. choice of command)
to be overridden on a per-device basis via sysfs. Two additional modes
are supported in this version:

 - WRITE SAME(10) with the UNMAP bit set

 - WRITE SAME(10) without the UNMAP bit set. This allows us to support
   devices that predate the TP/LBP enhancements in SBC3 and which work
   by way zero-detection

Switching between modes has been consolidated in a helper function that
also updates the block layer topology according to the limitations of
the chosen command.

I experimented with trying WRITE SAME(16) if UNMAP fails, WRITE SAME(10)
if WRITE SAME(16) fails, etc. but found several devices that got
cranky. So for now we'll disable discard if one of the commands
fail. The user still has the option of selecting a different mode in
sysfs.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 20 insertions, 5 deletions

diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index c9d8f6c..6ad798b 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -43,6 +43,15 @@ enum {
 	SD_MEMPOOL_SIZE = 2,	/* CDB pool size */
 };
 
+enum {
+	SD_LBP_FULL = 0,	/* Full logical block provisioning */
+	SD_LBP_UNMAP,		/* Use UNMAP command */
+	SD_LBP_WS16,		/* Use WRITE SAME(16) with UNMAP bit */
+	SD_LBP_WS10,		/* Use WRITE SAME(10) with UNMAP bit */
+	SD_LBP_ZERO,		/* Use WRITE SAME(10) with zero payload */
+	SD_LBP_DISABLE,		/* Discard disabled due to failed cmd */
+};
+
 struct scsi_disk {
 	struct scsi_driver *driver;	/* always &sd_template */
 	struct scsi_device *device;
@@ -50,21 +59,27 @@ struct scsi_disk {
 	struct gendisk	*disk;
 	atomic_t	openers;
 	sector_t	capacity;	/* size in 512-byte sectors */
+	u32		max_ws_blocks;
+	u32		max_unmap_blocks;
+	u32		unmap_granularity;
+	u32		unmap_alignment;
 	u32		index;
 	unsigned int	physical_block_size;
 	u8		media_present;
 	u8		write_prot;
 	u8		protection_type;/* Data Integrity Field */
+	u8		provisioning_mode;
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	WCE : 1;	/* state of disk WCE bit */
 	unsigned	RCD : 1;	/* state of disk RCD bit, unused */
 	unsigned	DPOFUA : 1;	/* state of disk DPOFUA bit */
 	unsigned	first_scan : 1;
-	unsigned	thin_provisioning : 1;
-	unsigned	unmap : 1;
-	unsigned	tpws : 1;
-	unsigned	tpu : 1;
-	unsigned	tpvpd : 1;
+	unsigned	lbpme : 1;
+	unsigned	lbprz : 1;
+	unsigned	lbpu : 1;
+	unsigned	lbpws : 1;
+	unsigned	lbpws10 : 1;
+	unsigned	lbpvpd : 1;
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)