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.
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
drivers/scsi/sd.c | 40 +++++++++++++++++++++++++++++++++++-----
drivers/scsi/sd.h | 2 ++
2 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8802e48..7d6a61c 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1991,14 +1991,19 @@ 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) {
+ if (sdkp->tpu && desc_count && lba_count)
+ sdkp->unmap = 1;
+ else if (!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;
- if (desc_count)
- sdkp->unmap = 1;
- }
-
granularity = get_unaligned_be32(&buffer[28]);
if (granularity)
@@ -2039,6 +2044,30 @@ 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->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)
{
/*
@@ -2090,6 +2119,7 @@ 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);
}
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 43d3caf..9646062 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -62,6 +62,8 @@ struct scsi_disk {
unsigned first_scan : 1;
unsigned thin_provisioning : 1;
unsigned unmap : 1;
+ unsigned tpws : 1;
+ unsigned tpu : 1;
};
#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)
--
1.7.2.1
--
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