lib: Introduce priority array area manager

This introduces a infrastructure for management of linear priority
areas. Priority order in an array matters, however order of items inside
a priority group does not matter.

As an initial implementation, L-sort algorithm is used. It is quite
trivial. More advanced algorithm called P-sort will be introduced as a
follow-up. The infrastructure is prepared for other algos.

Alongside this, a testing module is introduced as well.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -9382,6 +9382,14 @@ F:	drivers/video/fbdev/sti*
 F:	drivers/video/console/sti*
 F:	drivers/video/logo/logo_parisc*
 
+PARMAN
+M:	Jiri Pirko <jiri@mellanox.com>
+L:	netdev@vger.kernel.org
+S:	Supported
+F:	lib/parman.c
+F:	lib/test_parman.c
+F:	include/linux/parman.h
+
 PC87360 HARDWARE MONITORING DRIVER
 M:	Jim Cromie <jim.cromie@gmail.com>
 L:	linux-hwmon@vger.kernel.org

include/linux/parman.h

+/*
+ * include/linux/parman.h - Manager for linear priority array areas
+ * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2017 Jiri Pirko <jiri@mellanox.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _PARMAN_H
+#define _PARMAN_H
+
+#include <linux/list.h>
+
+enum parman_algo_type {
+	PARMAN_ALGO_TYPE_LSORT,
+};
+
+struct parman_item {
+	struct list_head list;
+	unsigned long index;
+};
+
+struct parman_prio {
+	struct list_head list;
+	struct list_head item_list;
+	unsigned long priority;
+};
+
+struct parman_ops {
+	unsigned long base_count;
+	unsigned long resize_step;
+	int (*resize)(void *priv, unsigned long new_count);
+	void (*move)(void *priv, unsigned long from_index,
+		     unsigned long to_index, unsigned long count);
+	enum parman_algo_type algo;
+};
+
+struct parman;
+
+struct parman *parman_create(const struct parman_ops *ops, void *priv);
+void parman_destroy(struct parman *parman);
+void parman_prio_init(struct parman *parman, struct parman_prio *prio,
+		      unsigned long priority);
+void parman_prio_fini(struct parman_prio *prio);
+int parman_item_add(struct parman *parman, struct parman_prio *prio,
+		    struct parman_item *item);
+void parman_item_remove(struct parman *parman, struct parman_prio *prio,
+			struct parman_item *item);
+
+#endif

lib/Kconfig

@@ -550,4 +550,7 @@ config STACKDEPOT
 config SBITMAP
 	bool
 
+config PARMAN
+	tristate "parman"
+
 endmenu

lib/Kconfig.debug

@@ -1826,6 +1826,16 @@ config TEST_HASH
 	  This is intended to help people writing architecture-specific
 	  optimized versions.  If unsure, say N.
 
+config TEST_PARMAN
+	tristate "Perform selftest on priority array manager"
+	default n
+	depends on PARMAN
+	help
+	  Enable this option to test priority array manager on boot
+	  (or module load).
+
+	  If unsure, say N.
+
 endmenu # runtime tests
 
 config PROVIDE_OHCI1394_DMA_INIT

lib/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
 obj-$(CONFIG_TEST_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
 obj-$(CONFIG_TEST_UUID) += test_uuid.o
+obj-$(CONFIG_TEST_PARMAN) += test_parman.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
 CFLAGS_kobject.o += -DDEBUG
@@ -230,3 +231,5 @@ obj-$(CONFIG_UBSAN) += ubsan.o
 UBSAN_SANITIZE_ubsan.o := n
 
 obj-$(CONFIG_SBITMAP) += sbitmap.o
+
+obj-$(CONFIG_PARMAN) += parman.o