target: Add EXPORT_SYMBOL for existing se_dev_set_*

Now that target_core_backend_configfs.h macros will be using these
se_dev_set attribute functions externally to allow backend drivers
to populate different attributes, go ahead and add EXPORT_SYMBOL()
for the existing default set of 30 device attributes.

Also update target_core_backend.h with proper function prototypes.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 83a3726..430cfaf 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -110,4 +110,33 @@
 /* From target_core_configfs.c to setup default backend config_item_types */
 void	target_core_setup_sub_cits(struct se_subsystem_api *);
 
+/* attribute helpers from target_core_device.c for backend drivers */
+int	se_dev_set_max_unmap_lba_count(struct se_device *, u32);
+int	se_dev_set_max_unmap_block_desc_count(struct se_device *, u32);
+int	se_dev_set_unmap_granularity(struct se_device *, u32);
+int	se_dev_set_unmap_granularity_alignment(struct se_device *, u32);
+int	se_dev_set_max_write_same_len(struct se_device *, u32);
+int	se_dev_set_emulate_model_alias(struct se_device *, int);
+int	se_dev_set_emulate_dpo(struct se_device *, int);
+int	se_dev_set_emulate_fua_write(struct se_device *, int);
+int	se_dev_set_emulate_fua_read(struct se_device *, int);
+int	se_dev_set_emulate_write_cache(struct se_device *, int);
+int	se_dev_set_emulate_ua_intlck_ctrl(struct se_device *, int);
+int	se_dev_set_emulate_tas(struct se_device *, int);
+int	se_dev_set_emulate_tpu(struct se_device *, int);
+int	se_dev_set_emulate_tpws(struct se_device *, int);
+int	se_dev_set_emulate_caw(struct se_device *, int);
+int	se_dev_set_emulate_3pc(struct se_device *, int);
+int	se_dev_set_pi_prot_type(struct se_device *, int);
+int	se_dev_set_pi_prot_format(struct se_device *, int);
+int	se_dev_set_enforce_pr_isids(struct se_device *, int);
+int	se_dev_set_force_pr_aptpl(struct se_device *, int);
+int	se_dev_set_is_nonrot(struct se_device *, int);
+int	se_dev_set_emulate_rest_reord(struct se_device *dev, int);
+int	se_dev_set_queue_depth(struct se_device *, u32);
+int	se_dev_set_max_sectors(struct se_device *, u32);
+int	se_dev_set_fabric_max_sectors(struct se_device *, u32);
+int	se_dev_set_optimal_sectors(struct se_device *, u32);
+int	se_dev_set_block_size(struct se_device *, u32);
+
 #endif /* TARGET_CORE_BACKEND_H */