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>

7 files changed, 871 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index c15dc53f9d66..a9368bba9b37 100644
--- a/MAINTAINERS
+++ b/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
diff --git a/include/linux/parman.h b/include/linux/parman.h
new file mode 100644
index 000000000000..3c8cccc7d4da
--- /dev/null
+++ b/include/linux/parman.h
@@ -0,0 +1,76 @@
+/*
+ * 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
diff --git a/lib/Kconfig b/lib/Kconfig
index 260a80e313b9..5d644f180fe5 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -550,4 +550,7 @@ config STACKDEPOT
 config SBITMAP
         bool
 
+config PARMAN
+        tristate "parman"
+
 endmenu
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 15969abf00a6..433a788500be 100644
--- a/lib/Kconfig.debug
+++ b/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
diff --git a/lib/Makefile b/lib/Makefile
index 7b3008d58600..1c039a4f60e5 100644
--- a/lib/Makefile
+++ b/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
diff --git a/lib/parman.c b/lib/parman.c
new file mode 100644
index 000000000000..c6e42a8db824
--- /dev/null
+++ b/lib/parman.c
@@ -0,0 +1,376 @@
+/*
+ * lib/parman.c - 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/list.h>
+#include <linux/err.h>
+#include <linux/parman.h>
+
+struct parman_algo {
+        int (*item_add)(struct parman *parman, struct parman_prio *prio,
+                        struct parman_item *item);
+        void (*item_remove)(struct parman *parman, struct parman_prio *prio,
+                            struct parman_item *item);
+};
+
+struct parman {
+        const struct parman_ops *ops;
+        void *priv;
+        const struct parman_algo *algo;
+        unsigned long count;
+        unsigned long limit_count;
+        struct list_head prio_list;
+};
+
+static int parman_enlarge(struct parman *parman)
+{
+        unsigned long new_count = parman->limit_count +
+                                  parman->ops->resize_step;
+        int err;
+
+        err = parman->ops->resize(parman->priv, new_count);
+        if (err)
+                return err;
+        parman->limit_count = new_count;
+        return 0;
+}
+
+static int parman_shrink(struct parman *parman)
+{
+        unsigned long new_count = parman->limit_count -
+                                  parman->ops->resize_step;
+        int err;
+
+        if (new_count < parman->ops->base_count)
+                return 0;
+        err = parman->ops->resize(parman->priv, new_count);
+        if (err)
+                return err;
+        parman->limit_count = new_count;
+        return 0;
+}
+
+static bool parman_prio_used(struct parman_prio *prio)
+
+{
+        return !list_empty(&prio->item_list);
+}
+
+static struct parman_item *parman_prio_first_item(struct parman_prio *prio)
+{
+        return list_first_entry(&prio->item_list,
+                                typeof(struct parman_item), list);
+}
+
+static unsigned long parman_prio_first_index(struct parman_prio *prio)
+{
+        return parman_prio_first_item(prio)->index;
+}
+
+static struct parman_item *parman_prio_last_item(struct parman_prio *prio)
+{
+        return list_last_entry(&prio->item_list,
+                               typeof(struct parman_item), list);
+}
+
+static unsigned long parman_prio_last_index(struct parman_prio *prio)
+{
+        return parman_prio_last_item(prio)->index;
+}
+
+static unsigned long parman_lsort_new_index_find(struct parman *parman,
+                                                 struct parman_prio *prio)
+{
+        list_for_each_entry_from_reverse(prio, &parman->prio_list, list) {
+                if (!parman_prio_used(prio))
+                        continue;
+                return parman_prio_last_index(prio) + 1;
+        }
+        return 0;
+}
+
+static void __parman_prio_move(struct parman *parman, struct parman_prio *prio,
+                               struct parman_item *item, unsigned long to_index,
+                               unsigned long count)
+{
+        parman->ops->move(parman->priv, item->index, to_index, count);
+}
+
+static void parman_prio_shift_down(struct parman *parman,
+                                   struct parman_prio *prio)
+{
+        struct parman_item *item;
+        unsigned long to_index;
+
+        if (!parman_prio_used(prio))
+                return;
+        item = parman_prio_first_item(prio);
+        to_index = parman_prio_last_index(prio) + 1;
+        __parman_prio_move(parman, prio, item, to_index, 1);
+        list_move_tail(&item->list, &prio->item_list);
+        item->index = to_index;
+}
+
+static void parman_prio_shift_up(struct parman *parman,
+                                 struct parman_prio *prio)
+{
+        struct parman_item *item;
+        unsigned long to_index;
+
+        if (!parman_prio_used(prio))
+                return;
+        item = parman_prio_last_item(prio);
+        to_index = parman_prio_first_index(prio) - 1;
+        __parman_prio_move(parman, prio, item, to_index, 1);
+        list_move(&item->list, &prio->item_list);
+        item->index = to_index;
+}
+
+static void parman_prio_item_remove(struct parman *parman,
+                                    struct parman_prio *prio,
+                                    struct parman_item *item)
+{
+        struct parman_item *last_item;
+        unsigned long to_index;
+
+        last_item = parman_prio_last_item(prio);
+        if (last_item == item) {
+                list_del(&item->list);
+                return;
+        }
+        to_index = item->index;
+        __parman_prio_move(parman, prio, last_item, to_index, 1);
+        list_del(&last_item->list);
+        list_replace(&item->list, &last_item->list);
+        last_item->index = to_index;
+}
+
+static int parman_lsort_item_add(struct parman *parman,
+                                 struct parman_prio *prio,
+                                 struct parman_item *item)
+{
+        struct parman_prio *prio2;
+        unsigned long new_index;
+        int err;
+
+        if (parman->count + 1 > parman->limit_count) {
+                err = parman_enlarge(parman);
+                if (err)
+                        return err;
+        }
+
+        new_index = parman_lsort_new_index_find(parman, prio);
+        list_for_each_entry_reverse(prio2, &parman->prio_list, list) {
+                if (prio2 == prio)
+                        break;
+                parman_prio_shift_down(parman, prio2);
+        }
+        item->index = new_index;
+        list_add_tail(&item->list, &prio->item_list);
+        parman->count++;
+        return 0;
+}
+
+static void parman_lsort_item_remove(struct parman *parman,
+                                     struct parman_prio *prio,
+                                     struct parman_item *item)
+{
+        parman_prio_item_remove(parman, prio, item);
+        list_for_each_entry_continue(prio, &parman->prio_list, list)
+                parman_prio_shift_up(parman, prio);
+        parman->count--;
+        if (parman->limit_count - parman->count >= parman->ops->resize_step)
+                parman_shrink(parman);
+}
+
+static const struct parman_algo parman_lsort = {
+        .item_add       = parman_lsort_item_add,
+        .item_remove    = parman_lsort_item_remove,
+};
+
+static const struct parman_algo *parman_algos[] = {
+        &parman_lsort,
+};
+
+/**
+ * parman_create - creates a new parman instance
+ * @ops:        caller-specific callbacks
+ * @priv:       pointer to a private data passed to the ops
+ *
+ * Note: all locking must be provided by the caller.
+ *
+ * Each parman instance manages an array area with chunks of entries
+ * with the same priority. Consider following example:
+ *
+ * item 1 with prio 10
+ * item 2 with prio 10
+ * item 3 with prio 10
+ * item 4 with prio 20
+ * item 5 with prio 20
+ * item 6 with prio 30
+ * item 7 with prio 30
+ * item 8 with prio 30
+ *
+ * In this example, there are 3 priority chunks. The order of the priorities
+ * matters, however the order of items within a single priority chunk does not
+ * matter. So the same array could be ordered as follows:
+ *
+ * item 2 with prio 10
+ * item 3 with prio 10
+ * item 1 with prio 10
+ * item 5 with prio 20
+ * item 4 with prio 20
+ * item 7 with prio 30
+ * item 8 with prio 30
+ * item 6 with prio 30
+ *
+ * The goal of parman is to maintain the priority ordering. The caller
+ * provides @ops with callbacks parman uses to move the items
+ * and resize the array area.
+ *
+ * Returns a pointer to newly created parman instance in case of success,
+ * otherwise it returns NULL.
+ */
+struct parman *parman_create(const struct parman_ops *ops, void *priv)
+{
+        struct parman *parman;
+
+        parman = kzalloc(sizeof(*parman), GFP_KERNEL);
+        if (!parman)
+                return NULL;
+        INIT_LIST_HEAD(&parman->prio_list);
+        parman->ops = ops;
+        parman->priv = priv;
+        parman->limit_count = ops->base_count;
+        parman->algo = parman_algos[ops->algo];
+        return parman;
+}
+EXPORT_SYMBOL(parman_create);
+
+/**
+ * parman_destroy - destroys existing parman instance
+ * @parman:     parman instance
+ *
+ * Note: all locking must be provided by the caller.
+ */
+void parman_destroy(struct parman *parman)
+{
+        WARN_ON(!list_empty(&parman->prio_list));
+        kfree(parman);
+}
+EXPORT_SYMBOL(parman_destroy);
+
+/**
+ * parman_prio_init - initializes a parman priority chunk
+ * @parman:     parman instance
+ * @prio:       parman prio structure to be initialized
+ * @prority:    desired priority of the chunk
+ *
+ * Note: all locking must be provided by the caller.
+ *
+ * Before caller could add an item with certain priority, he has to
+ * initialize a priority chunk for it using this function.
+ */
+void parman_prio_init(struct parman *parman, struct parman_prio *prio,
+                      unsigned long priority)
+{
+        struct parman_prio *prio2;
+        struct list_head *pos;
+
+        INIT_LIST_HEAD(&prio->item_list);
+        prio->priority = priority;
+
+        /* Position inside the list according to priority */
+        list_for_each(pos, &parman->prio_list) {
+                prio2 = list_entry(pos, typeof(*prio2), list);
+                if (prio2->priority > prio->priority)
+                        break;
+        }
+        list_add_tail(&prio->list, pos);
+}
+EXPORT_SYMBOL(parman_prio_init);
+
+/**
+ * parman_prio_fini - finalizes use of parman priority chunk
+ * @prio:       parman prio structure
+ *
+ * Note: all locking must be provided by the caller.
+ */
+void parman_prio_fini(struct parman_prio *prio)
+{
+        WARN_ON(parman_prio_used(prio));
+        list_del(&prio->list);
+}
+EXPORT_SYMBOL(parman_prio_fini);
+
+/**
+ * parman_item_add - adds a parman item under defined priority
+ * @parman:     parman instance
+ * @prio:       parman prio instance to add the item to
+ * @item:       parman item instance
+ *
+ * Note: all locking must be provided by the caller.
+ *
+ * Adds item to a array managed by parman instance under the specified priority.
+ *
+ * Returns 0 in case of success, negative number to indicate an error.
+ */
+int parman_item_add(struct parman *parman, struct parman_prio *prio,
+                    struct parman_item *item)
+{
+        return parman->algo->item_add(parman, prio, item);
+}
+EXPORT_SYMBOL(parman_item_add);
+
+/**
+ * parman_item_del - deletes parman item
+ * @parman:     parman instance
+ * @prio:       parman prio instance to delete the item from
+ * @item:       parman item instance
+ *
+ * Note: all locking must be provided by the caller.
+ */
+void parman_item_remove(struct parman *parman, struct parman_prio *prio,
+                        struct parman_item *item)
+{
+        parman->algo->item_remove(parman, prio, item);
+}
+EXPORT_SYMBOL(parman_item_remove);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
+MODULE_DESCRIPTION("Priority-based array manager");
diff --git a/lib/test_parman.c b/lib/test_parman.c
new file mode 100644
index 000000000000..fe9f3a785804
--- /dev/null
+++ b/lib/test_parman.c
@@ -0,0 +1,395 @@
+/*
+ * lib/test_parman.c - Test module for parman
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/random.h>
+#include <linux/parman.h>
+
+#define TEST_PARMAN_PRIO_SHIFT 7 /* defines number of prios for testing */
+#define TEST_PARMAN_PRIO_COUNT BIT(TEST_PARMAN_PRIO_SHIFT)
+#define TEST_PARMAN_PRIO_MASK (TEST_PARMAN_PRIO_COUNT - 1)
+
+#define TEST_PARMAN_ITEM_SHIFT 13 /* defines a total number
+                                   * of items for testing
+                                   */
+#define TEST_PARMAN_ITEM_COUNT BIT(TEST_PARMAN_ITEM_SHIFT)
+#define TEST_PARMAN_ITEM_MASK (TEST_PARMAN_ITEM_COUNT - 1)
+
+#define TEST_PARMAN_BASE_SHIFT 8
+#define TEST_PARMAN_BASE_COUNT BIT(TEST_PARMAN_BASE_SHIFT)
+#define TEST_PARMAN_RESIZE_STEP_SHIFT 7
+#define TEST_PARMAN_RESIZE_STEP_COUNT BIT(TEST_PARMAN_RESIZE_STEP_SHIFT)
+
+#define TEST_PARMAN_BULK_MAX_SHIFT (2 + TEST_PARMAN_RESIZE_STEP_SHIFT)
+#define TEST_PARMAN_BULK_MAX_COUNT BIT(TEST_PARMAN_BULK_MAX_SHIFT)
+#define TEST_PARMAN_BULK_MAX_MASK (TEST_PARMAN_BULK_MAX_COUNT - 1)
+
+#define TEST_PARMAN_RUN_BUDGET (TEST_PARMAN_ITEM_COUNT * 256)
+
+struct test_parman_prio {
+        struct parman_prio parman_prio;
+        unsigned long priority;
+};
+
+struct test_parman_item {
+        struct parman_item parman_item;
+        struct test_parman_prio *prio;
+        bool used;
+};
+
+struct test_parman {
+        struct parman *parman;
+        struct test_parman_item **prio_array;
+        unsigned long prio_array_limit;
+        struct test_parman_prio prios[TEST_PARMAN_PRIO_COUNT];
+        struct test_parman_item items[TEST_PARMAN_ITEM_COUNT];
+        struct rnd_state rnd;
+        unsigned long run_budget;
+        unsigned long bulk_budget;
+        bool bulk_noop;
+        unsigned int used_items;
+};
+
+#define ITEM_PTRS_SIZE(count) (sizeof(struct test_parman_item *) * (count))
+
+static int test_parman_resize(void *priv, unsigned long new_count)
+{
+        struct test_parman *test_parman = priv;
+        struct test_parman_item **prio_array;
+        unsigned long old_count;
+
+        prio_array = krealloc(test_parman->prio_array,
+                              ITEM_PTRS_SIZE(new_count), GFP_KERNEL);
+        if (new_count == 0)
+                return 0;
+        if (!prio_array)
+                return -ENOMEM;
+        old_count = test_parman->prio_array_limit;
+        if (new_count > old_count)
+                memset(&prio_array[old_count], 0,
+                       ITEM_PTRS_SIZE(new_count - old_count));
+        test_parman->prio_array = prio_array;
+        test_parman->prio_array_limit = new_count;
+        return 0;
+}
+
+static void test_parman_move(void *priv, unsigned long from_index,
+                             unsigned long to_index, unsigned long count)
+{
+        struct test_parman *test_parman = priv;
+        struct test_parman_item **prio_array = test_parman->prio_array;
+
+        memmove(&prio_array[to_index], &prio_array[from_index],
+                ITEM_PTRS_SIZE(count));
+        memset(&prio_array[from_index], 0, ITEM_PTRS_SIZE(count));
+}
+
+static const struct parman_ops test_parman_lsort_ops = {
+        .base_count     = TEST_PARMAN_BASE_COUNT,
+        .resize_step    = TEST_PARMAN_RESIZE_STEP_COUNT,
+        .resize         = test_parman_resize,
+        .move           = test_parman_move,
+        .algo           = PARMAN_ALGO_TYPE_LSORT,
+};
+
+static void test_parman_rnd_init(struct test_parman *test_parman)
+{
+        prandom_seed_state(&test_parman->rnd, 3141592653589793238ULL);
+}
+
+static u32 test_parman_rnd_get(struct test_parman *test_parman)
+{
+        return prandom_u32_state(&test_parman->rnd);
+}
+
+static unsigned long test_parman_priority_gen(struct test_parman *test_parman)
+{
+        unsigned long priority;
+        int i;
+
+again:
+        priority = test_parman_rnd_get(test_parman);
+        if (priority == 0)
+                goto again;
+
+        for (i = 0; i < TEST_PARMAN_PRIO_COUNT; i++) {
+                struct test_parman_prio *prio = &test_parman->prios[i];
+
+                if (prio->priority == 0)
+                        break;
+                if (prio->priority == priority)
+                        goto again;
+        }
+        return priority;
+}
+
+static void test_parman_prios_init(struct test_parman *test_parman)
+{
+        int i;
+
+        for (i = 0; i < TEST_PARMAN_PRIO_COUNT; i++) {
+                struct test_parman_prio *prio = &test_parman->prios[i];
+
+                /* Assign random uniqueue priority to each prio structure */
+                prio->priority = test_parman_priority_gen(test_parman);
+                parman_prio_init(test_parman->parman, &prio->parman_prio,
+                                 prio->priority);
+        }
+}
+
+static void test_parman_prios_fini(struct test_parman *test_parman)
+{
+        int i;
+
+        for (i = 0; i < TEST_PARMAN_PRIO_COUNT; i++) {
+                struct test_parman_prio *prio = &test_parman->prios[i];
+
+                parman_prio_fini(&prio->parman_prio);
+        }
+}
+
+static void test_parman_items_init(struct test_parman *test_parman)
+{
+        int i;
+
+        for (i = 0; i < TEST_PARMAN_ITEM_COUNT; i++) {
+                struct test_parman_item *item = &test_parman->items[i];
+                unsigned int prio_index = test_parman_rnd_get(test_parman) &
+                                          TEST_PARMAN_PRIO_MASK;
+
+                /* Assign random prio to each item structure */
+                item->prio = &test_parman->prios[prio_index];
+        }
+}
+
+static void test_parman_items_fini(struct test_parman *test_parman)
+{
+        int i;
+
+        for (i = 0; i < TEST_PARMAN_ITEM_COUNT; i++) {
+                struct test_parman_item *item = &test_parman->items[i];
+
+                if (!item->used)
+                        continue;
+                parman_item_remove(test_parman->parman,
+                                   &item->prio->parman_prio,
+                                   &item->parman_item);
+        }
+}
+
+static struct test_parman *test_parman_create(const struct parman_ops *ops)
+{
+        struct test_parman *test_parman;
+        int err;
+
+        test_parman = kzalloc(sizeof(*test_parman), GFP_KERNEL);
+        if (!test_parman)
+                return ERR_PTR(-ENOMEM);
+        err = test_parman_resize(test_parman, TEST_PARMAN_BASE_COUNT);
+        if (err)
+                goto err_resize;
+        test_parman->parman = parman_create(ops, test_parman);
+        if (!test_parman->parman) {
+                err = -ENOMEM;
+                goto err_parman_create;
+        }
+        test_parman_rnd_init(test_parman);
+        test_parman_prios_init(test_parman);
+        test_parman_items_init(test_parman);
+        test_parman->run_budget = TEST_PARMAN_RUN_BUDGET;
+        return test_parman;
+
+err_parman_create:
+        test_parman_resize(test_parman, 0);
+err_resize:
+        kfree(test_parman);
+        return ERR_PTR(err);
+}
+
+static void test_parman_destroy(struct test_parman *test_parman)
+{
+        test_parman_items_fini(test_parman);
+        test_parman_prios_fini(test_parman);
+        parman_destroy(test_parman->parman);
+        test_parman_resize(test_parman, 0);
+        kfree(test_parman);
+}
+
+static bool test_parman_run_check_budgets(struct test_parman *test_parman)
+{
+        if (test_parman->run_budget-- == 0)
+                return false;
+        if (test_parman->bulk_budget-- != 0)
+                return true;
+
+        test_parman->bulk_budget = test_parman_rnd_get(test_parman) &
+                                   TEST_PARMAN_BULK_MAX_MASK;
+        test_parman->bulk_noop = test_parman_rnd_get(test_parman) & 1;
+        return true;
+}
+
+static int test_parman_run(struct test_parman *test_parman)
+{
+        unsigned int i = test_parman_rnd_get(test_parman);
+        int err;
+
+        while (test_parman_run_check_budgets(test_parman)) {
+                unsigned int item_index = i++ & TEST_PARMAN_ITEM_MASK;
+                struct test_parman_item *item = &test_parman->items[item_index];
+
+                if (test_parman->bulk_noop)
+                        continue;
+
+                if (!item->used) {
+                        err = parman_item_add(test_parman->parman,
+                                              &item->prio->parman_prio,
+                                              &item->parman_item);
+                        if (err)
+                                return err;
+                        test_parman->prio_array[item->parman_item.index] = item;
+                        test_parman->used_items++;
+                } else {
+                        test_parman->prio_array[item->parman_item.index] = NULL;
+                        parman_item_remove(test_parman->parman,
+                                           &item->prio->parman_prio,
+                                           &item->parman_item);
+                        test_parman->used_items--;
+                }
+                item->used = !item->used;
+        }
+        return 0;
+}
+
+static int test_parman_check_array(struct test_parman *test_parman,
+                                   bool gaps_allowed)
+{
+        unsigned int last_unused_items = 0;
+        unsigned long last_priority = 0;
+        unsigned int used_items = 0;
+        int i;
+
+        if (test_parman->prio_array_limit < TEST_PARMAN_BASE_COUNT) {
+                pr_err("Array limit is lower than the base count (%lu < %lu)\n",
+                       test_parman->prio_array_limit, TEST_PARMAN_BASE_COUNT);
+                return -EINVAL;
+        }
+
+        for (i = 0; i < test_parman->prio_array_limit; i++) {
+                struct test_parman_item *item = test_parman->prio_array[i];
+
+                if (!item) {
+                        last_unused_items++;
+                        continue;
+                }
+                if (last_unused_items && !gaps_allowed) {
+                        pr_err("Gap found in array even though they are forbidden\n");
+                        return -EINVAL;
+                }
+
+                last_unused_items = 0;
+                used_items++;
+
+                if (item->prio->priority < last_priority) {
+                        pr_err("Item belongs under higher priority then the last one (current: %lu, previous: %lu)\n",
+                               item->prio->priority, last_priority);
+                        return -EINVAL;
+                }
+                last_priority = item->prio->priority;
+
+                if (item->parman_item.index != i) {
+                        pr_err("Item has different index in compare to where it actualy is (%lu != %d)\n",
+                               item->parman_item.index, i);
+                        return -EINVAL;
+                }
+        }
+
+        if (used_items != test_parman->used_items) {
+                pr_err("Number of used items in array does not match (%u != %u)\n",
+                       used_items, test_parman->used_items);
+                return -EINVAL;
+        }
+
+        if (last_unused_items >= TEST_PARMAN_RESIZE_STEP_COUNT) {
+                pr_err("Number of unused item at the end of array is bigger than resize step (%u >= %lu)\n",
+                       last_unused_items, TEST_PARMAN_RESIZE_STEP_COUNT);
+                return -EINVAL;
+        }
+
+        pr_info("Priority array check successful\n");
+
+        return 0;
+}
+
+static int test_parman_lsort(void)
+{
+        struct test_parman *test_parman;
+        int err;
+
+        test_parman = test_parman_create(&test_parman_lsort_ops);
+        if (IS_ERR(test_parman))
+                return PTR_ERR(test_parman);
+
+        err = test_parman_run(test_parman);
+        if (err)
+                goto out;
+
+        err = test_parman_check_array(test_parman, false);
+        if (err)
+                goto out;
+out:
+        test_parman_destroy(test_parman);
+        return err;
+}
+
+static int __init test_parman_init(void)
+{
+        return test_parman_lsort();
+}
+
+static void __exit test_parman_exit(void)
+{
+}
+
+module_init(test_parman_init);
+module_exit(test_parman_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
+MODULE_DESCRIPTION("Test module for parman");