drm: Declare hashtable as legacy

The DRM hashtable code is only used by internal functions for legacy
UMS drivers. Move the implementation behind CONFIG_DRM_LEGACY and the
declarations into legacy header files. Unexport the symbols.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129094841.22499-4-tzimmermann@suse.de

drivers/gpu/drm/Makefile

@@ -6,7 +6,7 @@
 drm-y       :=	drm_aperture.o drm_auth.o drm_cache.o \
 		drm_file.o drm_gem.o drm_ioctl.o \
 		drm_drv.o \
-		drm_sysfs.o drm_hashtab.o drm_mm.o \
+		drm_sysfs.o drm_mm.o \
 		drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o drm_displayid.o \
 		drm_trace_points.o drm_prime.o \
 		drm_vma_manager.o \
@@ -20,8 +20,8 @@ drm-y       :=	drm_aperture.o drm_auth.o drm_cache.o \
 		drm_managed.o drm_vblank_work.o
 
 drm-$(CONFIG_DRM_LEGACY) += drm_agpsupport.o drm_bufs.o drm_context.o drm_dma.o \
-			    drm_irq.o drm_legacy_misc.o drm_lock.o drm_memory.o \
-			    drm_scatter.o drm_vm.o
+			    drm_hashtab.o drm_irq.o drm_legacy_misc.o drm_lock.o \
+			    drm_memory.o drm_scatter.o drm_vm.o
 drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 drm-$(CONFIG_DRM_PANEL) += drm_panel.o

drivers/gpu/drm/drm_hashtab.c

@@ -32,16 +32,16 @@
  * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
  */
 
-#include <linux/export.h>
 #include <linux/hash.h>
 #include <linux/mm.h>
 #include <linux/rculist.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
-#include <drm/drm_hashtab.h>
 #include <drm/drm_print.h>
 
+#include "drm_legacy.h"
+
 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
 {
 	unsigned int size = 1 << order;
@@ -58,7 +58,6 @@ int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
 	}
 	return 0;
 }
-EXPORT_SYMBOL(drm_ht_create);
 
 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
 {
@@ -135,7 +134,6 @@ int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 	}
 	return 0;
 }
-EXPORT_SYMBOL(drm_ht_insert_item);
 
 /*
  * Just insert an item and return any "bits" bit key that hasn't been
@@ -164,7 +162,6 @@ int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *it
 	}
 	return 0;
 }
-EXPORT_SYMBOL(drm_ht_just_insert_please);
 
 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
 		     struct drm_hash_item **item)
@@ -178,7 +175,6 @@ int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
 	*item = hlist_entry(list, struct drm_hash_item, head);
 	return 0;
 }
-EXPORT_SYMBOL(drm_ht_find_item);
 
 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
 {
@@ -197,7 +193,6 @@ int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 	hlist_del_init_rcu(&item->head);
 	return 0;
 }
-EXPORT_SYMBOL(drm_ht_remove_item);
 
 void drm_ht_remove(struct drm_open_hash *ht)
 {
@@ -206,4 +201,3 @@ void drm_ht_remove(struct drm_open_hash *ht)
 		ht->table = NULL;
 	}
 }
-EXPORT_SYMBOL(drm_ht_remove);

drivers/gpu/drm/drm_legacy.h

@@ -35,9 +35,47 @@
 #include <drm/drm_legacy.h>
 
 struct agp_memory;
+struct drm_buf_desc;
 struct drm_device;
 struct drm_file;
-struct drm_buf_desc;
+struct drm_hash_item;
+struct drm_open_hash;
+
+/*
+ * Hash-table Support
+ */
+
+#define drm_hash_entry(_ptr, _type, _member) container_of(_ptr, _type, _member)
+
+/* drm_hashtab.c */
+#if IS_ENABLED(CONFIG_DRM_LEGACY)
+int drm_ht_create(struct drm_open_hash *ht, unsigned int order);
+int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item);
+int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
+			      unsigned long seed, int bits, int shift,
+			      unsigned long add);
+int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, struct drm_hash_item **item);
+
+void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key);
+int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key);
+int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item);
+void drm_ht_remove(struct drm_open_hash *ht);
+#endif
+
+/*
+ * RCU-safe interface
+ *
+ * The user of this API needs to make sure that two or more instances of the
+ * hash table manipulation functions are never run simultaneously.
+ * The lookup function drm_ht_find_item_rcu may, however, run simultaneously
+ * with any of the manipulation functions as long as it's called from within
+ * an RCU read-locked section.
+ */
+#define drm_ht_insert_item_rcu drm_ht_insert_item
+#define drm_ht_just_insert_please_rcu drm_ht_just_insert_please
+#define drm_ht_remove_key_rcu drm_ht_remove_key
+#define drm_ht_remove_item_rcu drm_ht_remove_item
+#define drm_ht_find_item_rcu drm_ht_find_item
 
 /*
  * Generic DRM Contexts

include/drm/drm_device.h

@@ -6,16 +6,13 @@
 #include <linux/mutex.h>
 #include <linux/idr.h>
 
-#include <drm/drm_hashtab.h>
+#include <drm/drm_legacy.h>
 #include <drm/drm_mode_config.h>
 
 struct drm_driver;
 struct drm_minor;
 struct drm_master;
-struct drm_device_dma;
 struct drm_vblank_crtc;
-struct drm_sg_mem;
-struct drm_local_map;
 struct drm_vma_offset_manager;
 struct drm_vram_mm;
 struct drm_fb_helper;

include/drm/drm_legacy.h

@@ -37,7 +37,6 @@
 
 #include <drm/drm.h>
 #include <drm/drm_auth.h>
-#include <drm/drm_hashtab.h>
 
 struct drm_device;
 struct drm_driver;
@@ -51,6 +50,20 @@ struct pci_driver;
  * you're doing it terribly wrong.
  */
 
+/*
+ * Hash-table Support
+ */
+
+struct drm_hash_item {
+	struct hlist_node head;
+	unsigned long key;
+};
+
+struct drm_open_hash {
+	struct hlist_head *table;
+	u8 order;
+};
+
 /**
  * DMA buffer.
  */