[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: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8c9b275..0c4f89cf 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2039,14 +2039,24 @@
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 @@
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 @@
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);
}
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 315ce9d..a40730e 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -63,6 +63,9 @@
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)