target/sbc: Add LBPRZ attribute + control CDB emulation
This change sets the LBPRZ flag in EVPD page b2h and READ CAPACITY (16)
based on a new unmap_zeroes_data device attribute. This flag is set
automatically for iblock based on underlying block device queue's
discard_zeroes_data flag.
Signed-off-by: Jamie Pocas <jamie.pocas@emc.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 2e47fe6..affe4c3 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -499,6 +499,7 @@
DEF_CONFIGFS_ATTRIB_SHOW(max_unmap_block_desc_count);
DEF_CONFIGFS_ATTRIB_SHOW(unmap_granularity);
DEF_CONFIGFS_ATTRIB_SHOW(unmap_granularity_alignment);
+DEF_CONFIGFS_ATTRIB_SHOW(unmap_zeroes_data);
DEF_CONFIGFS_ATTRIB_SHOW(max_write_same_len);
#define DEF_CONFIGFS_ATTRIB_STORE_U32(_name) \
@@ -866,6 +867,39 @@
return count;
}
+static ssize_t unmap_zeroes_data_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct se_dev_attrib *da = to_attrib(item);
+ bool flag;
+ int ret;
+
+ ret = strtobool(page, &flag);
+ if (ret < 0)
+ return ret;
+
+ if (da->da_dev->export_count) {
+ pr_err("dev[%p]: Unable to change SE Device"
+ " unmap_zeroes_data while export_count is %d\n",
+ da->da_dev, da->da_dev->export_count);
+ return -EINVAL;
+ }
+ /*
+ * We expect this value to be non-zero when generic Block Layer
+ * Discard supported is detected iblock_configure_device().
+ */
+ if (flag && !da->max_unmap_block_desc_count) {
+ pr_err("dev[%p]: Thin Provisioning LBPRZ will not be set"
+ " because max_unmap_block_desc_count is zero\n",
+ da->da_dev);
+ return -ENOSYS;
+ }
+ da->unmap_zeroes_data = flag;
+ pr_debug("dev[%p]: SE Device Thin Provisioning LBPRZ bit: %d\n",
+ da->da_dev, flag);
+ return 0;
+}
+
/*
* Note, this can only be called on unexported SE Device Object.
*/
@@ -998,6 +1032,7 @@
CONFIGFS_ATTR(, max_unmap_block_desc_count);
CONFIGFS_ATTR(, unmap_granularity);
CONFIGFS_ATTR(, unmap_granularity_alignment);
+CONFIGFS_ATTR(, unmap_zeroes_data);
CONFIGFS_ATTR(, max_write_same_len);
/*
@@ -1034,6 +1069,7 @@
&attr_max_unmap_block_desc_count,
&attr_unmap_granularity,
&attr_unmap_granularity_alignment,
+ &attr_unmap_zeroes_data,
&attr_max_write_same_len,
NULL,
};
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 88ea4e4..cacd97a 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -813,6 +813,8 @@
dev->dev_attrib.unmap_granularity = DA_UNMAP_GRANULARITY_DEFAULT;
dev->dev_attrib.unmap_granularity_alignment =
DA_UNMAP_GRANULARITY_ALIGNMENT_DEFAULT;
+ dev->dev_attrib.unmap_zeroes_data =
+ DA_UNMAP_ZEROES_DATA_DEFAULT;
dev->dev_attrib.max_write_same_len = DA_MAX_WRITE_SAME_LEN;
xcopy_lun = &dev->xcopy_lun;
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index f29c691..e77d150 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -138,6 +138,8 @@
q->limits.discard_granularity >> 9;
dev->dev_attrib.unmap_granularity_alignment =
q->limits.discard_alignment;
+ dev->dev_attrib.unmap_zeroes_data =
+ q->limits.discard_zeroes_data;
pr_debug("IBLOCK: BLOCK Discard support available,"
" disabled by default\n");
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 0b4b2a6..b83ac37 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -141,9 +141,17 @@
* Set Thin Provisioning Enable bit following sbc3r22 in section
* READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
*/
- if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws)
+ if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws) {
buf[14] |= 0x80;
+ /*
+ * LBPRZ signifies that zeroes will be read back from an LBA after
+ * an UNMAP or WRITE SAME w/ unmap bit (sbc3r36 5.16.2)
+ */
+ if (dev->dev_attrib.unmap_zeroes_data)
+ buf[14] |= 0x40;
+ }
+
rbuf = transport_kmap_data_sg(cmd);
if (rbuf) {
memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 9413e1a..0aa47ba 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -635,6 +635,18 @@
if (dev->dev_attrib.emulate_tpws != 0)
buf[5] |= 0x40 | 0x20;
+ /*
+ * The unmap_zeroes_data set means that the underlying device supports
+ * REQ_DISCARD and has the discard_zeroes_data bit set. This satisfies
+ * the SBC requirements for LBPRZ, meaning that a subsequent read
+ * will return zeroes after an UNMAP or WRITE SAME (16) to an LBA
+ * See sbc4r36 6.6.4.
+ */
+ if (((dev->dev_attrib.emulate_tpu != 0) ||
+ (dev->dev_attrib.emulate_tpws != 0)) &&
+ (dev->dev_attrib.unmap_zeroes_data != 0))
+ buf[5] |= 0x04;
+
return 0;
}