target: add helper to iterate over devices

This adds a wrapper around idr_for_each so the xcopy code can loop over
the devices in the next patch.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index de11316..bd32a0c 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -904,6 +904,51 @@ struct se_device *target_find_device(int id, bool do_depend)
 }
 EXPORT_SYMBOL(target_find_device);
 
+struct devices_idr_iter {
+       int (*fn)(struct se_device *dev, void *data);
+       void *data;
+};
+
+static int target_devices_idr_iter(int id, void *p, void *data)
+{
+       struct devices_idr_iter *iter = data;
+       struct se_device *dev = p;
+
+       /*
+        * We add the device early to the idr, so it can be used
+        * by backend modules during configuration. We do not want
+        * to allow other callers to access partially setup devices,
+        * so we skip them here.
+        */
+       if (!(dev->dev_flags & DF_CONFIGURED))
+               return 0;
+
+       return iter->fn(dev, iter->data);
+}
+
+/**
+ * target_for_each_device - iterate over configured devices
+ * @fn: iterator function
+ * @data: pointer to data that will be passed to fn
+ *
+ * fn must return 0 to continue looping over devices. non-zero will break
+ * from the loop and return that value to the caller.
+ */
+int target_for_each_device(int (*fn)(struct se_device *dev, void *data),
+                          void *data)
+{
+       struct devices_idr_iter iter;
+       int ret;
+
+       iter.fn = fn;
+       iter.data = data;
+
+       mutex_lock(&g_device_mutex);
+       ret = idr_for_each(&devices_idr, target_devices_idr_iter, &iter);
+       mutex_unlock(&g_device_mutex);
+       return ret;
+}
+
 int target_configure_device(struct se_device *dev)
 {
        struct se_hba *hba = dev->se_hba;

diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 0912de7..1d3ac02 100644 (file)
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -87,6 +87,8 @@ void  core_dev_release_virtual_lun0(void);
 struct se_device *target_alloc_device(struct se_hba *hba, const char *name);
 int    target_configure_device(struct se_device *dev);
 void   target_free_device(struct se_device *);
+int    target_for_each_device(int (*fn)(struct se_device *dev, void *data),
+                              void *data);
 
 /* target_core_configfs.c */
 void   target_setup_backend_cits(struct target_backend *);