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[04/12] target: add helper to find se_device by dev_index

Message ID 1498080791-13565-5-git-send-email-mchristi@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mike Christie June 21, 2017, 9:33 p.m. UTC 
This adds a helper to find a se_device by dev_index. It will
be used in the next patches so tcmu's netlink interface can
execute commands on specific devices.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>

---

Changes:
- Add depend/undepend support.

 drivers/target/target_core_device.c  | 24 ++++++++++++++++++++++++
 include/target/target_core_backend.h |  2 ++
 2 files changed, 26 insertions(+)
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Patch

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index d6fc8c0..aa69f34 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -880,6 +880,30 @@  sector_t target_to_linux_sector(struct se_device *dev, sector_t lb)
 }
 EXPORT_SYMBOL(target_to_linux_sector);
 
+/**
+ * target_find_device - find a se_device by its dev_index
+ * @id: dev_index
+ * @do_depend: true if caller needs target_depend_item to be done
+ *
+ * If do_depend is true, the caller must do a target_undepend_item
+ * when finished using the device.
+ *
+ * If do_depend is false, the caller must be called in a configfs
+ * callback or during removal.
+ */
+struct se_device *target_find_device(int id, bool do_depend)
+{
+	struct se_device *dev;
+
+	mutex_lock(&g_device_mutex);
+	dev = idr_find(&devices_idr, id);
+	if (dev && do_depend && target_depend_item(&dev->dev_group.cg_item))
+		dev = NULL;
+	mutex_unlock(&g_device_mutex);
+	return dev;
+}
+EXPORT_SYMBOL(target_find_device);
+
 int target_configure_device(struct se_device *dev)
 {
 	struct se_hba *hba = dev->se_hba;
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 3dbcacd..1f2b700 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -106,6 +106,8 @@  sense_reason_t	transport_generic_map_mem_to_cmd(struct se_cmd *,
 sense_reason_t passthrough_parse_cdb(struct se_cmd *cmd,
 	sense_reason_t (*exec_cmd)(struct se_cmd *cmd));
 
+struct	se_device *target_find_device(int id, bool do_depend);
+
 bool target_sense_desc_format(struct se_device *dev);
 sector_t target_to_linux_sector(struct se_device *dev, sector_t lb);
 bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,