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Commit 045d3fe7 authored by Martin K. Petersen's avatar Martin K. Petersen Committed by James Bottomley
Browse files

[SCSI] sd: Update thin provisioning support 



Add support for the Thin Provisioning VPD page and use the TPU and TPWS
bits to switch between UNMAP and WRITE SAME(16) for discards.  If no TP
VPD page is present we fall back to old scheme where the max descriptor
count combined with the max lba count are used trigger UNMAP.

Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent a36c61f9

drivers/scsi/sd.c

+41 −5
Original line number Diff line number Diff line
@@ -2039,14 +2039,24 @@ static void sd_read_block_limits(struct scsi_disk *sdkp) 
		lba_count = get_unaligned_be32(&buffer[20]);

		desc_count = get_unaligned_be32(&buffer[24]);



		if (lba_count) {

			q->limits.max_discard_sectors =

				lba_count * sector_sz >> 9;



			if (desc_count)

		if (lba_count && desc_count) {

			if (sdkp->tpvpd && !sdkp->tpu)

				sdkp->unmap = 0;

			else

				sdkp->unmap = 1;

		}



		if (sdkp->tpvpd && !sdkp->tpu && !sdkp->tpws) {

			sd_printk(KERN_ERR, sdkp, "Thin provisioning is " \

				  "enabled but neither TPU, nor TPWS are " \

				  "set. Disabling discard!\n");

			goto out;

		}



		if (lba_count)

			q->limits.max_discard_sectors =

				lba_count * sector_sz >> 9;



		granularity = get_unaligned_be32(&buffer[28]);



		if (granularity)
@@ -2087,6 +2097,31 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp) 
	kfree(buffer);

}



/**

 * sd_read_thin_provisioning - Query thin provisioning VPD page

 * @disk: disk to query

 */

static void sd_read_thin_provisioning(struct scsi_disk *sdkp)

{

	unsigned char *buffer;

	const int vpd_len = 8;



	if (sdkp->thin_provisioning == 0)

		return;



	buffer = kmalloc(vpd_len, GFP_KERNEL);



	if (!buffer || scsi_get_vpd_page(sdkp->device, 0xb2, buffer, vpd_len))

		goto out;



	sdkp->tpvpd = 1;

	sdkp->tpu   = (buffer[5] >> 7) & 1;	/* UNMAP */

	sdkp->tpws  = (buffer[5] >> 6) & 1;	/* WRITE SAME(16) with UNMAP */



 out:

	kfree(buffer);

}



static int sd_try_extended_inquiry(struct scsi_device *sdp)

{

	/*
@@ -2138,6 +2173,7 @@ static int sd_revalidate_disk(struct gendisk *disk) 
		sd_read_capacity(sdkp, buffer);



		if (sd_try_extended_inquiry(sdp)) {

			sd_read_thin_provisioning(sdkp);

			sd_read_block_limits(sdkp);

			sd_read_block_characteristics(sdkp);

		}

drivers/scsi/sd.h

+3 −0
Original line number Diff line number Diff line
@@ -63,6 +63,9 @@ struct scsi_disk { 
	unsigned	first_scan : 1;

	unsigned	thin_provisioning : 1;

	unsigned	unmap : 1;

	unsigned	tpws : 1;

	unsigned	tpu : 1;

	unsigned	tpvpd : 1;

};

#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)