[PATCH 2/5] scsi: target: Add callout to configure unmap settings

[Mike Christie <michael.christie@oracle.com>]

This patch adds a callout to configure a backend's unmap settings. This
will be used in this patchset to allow userspace to setup unmap after
the initial device setup similar to how we can setup the other attrs
post device configuration.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/target/target_core_device.c  | 6 ++++++
 include/target/target_core_backend.h | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 25f33eb25337..086ac9c9343c 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -960,6 +960,12 @@ int target_configure_device(struct se_device *dev)
 	ret = dev->transport->configure_device(dev);
 	if (ret)
 		goto out_free_index;
+
+	if (dev->transport->configure_unmap &&
+	    dev->transport->configure_unmap(dev)) {
+		pr_debug("Discard support available, but disabled by default.\n");
+	}
+
 	/*
 	 * XXX: there is not much point to have two different values here..
 	 */
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 773963a1e0b5..a3c193df25b3 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -37,6 +37,7 @@ struct target_backend_ops {
 	struct se_dev_plug *(*plug_device)(struct se_device *se_dev);
 	void (*unplug_device)(struct se_dev_plug *se_plug);
 
+	bool (*configure_unmap)(struct se_device *se_dev);
 	ssize_t (*set_configfs_dev_params)(struct se_device *,
 					   const char *, ssize_t);
 	ssize_t (*show_configfs_dev_params)(struct se_device *, char *);
-- 
2.25.1