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,
};