/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/ptlrpc/sec_bulk.c
 *
 * Author: Eric Mei <ericm@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_SEC

#include <linux/libcfs/libcfs.h>
#include <linux/crypto.h>

#include <obd.h>
#include <obd_cksum.h>
#include <obd_class.h>
#include <obd_support.h>
#include <lustre_net.h>
#include <lustre_import.h>
#include <lustre_dlm.h>
#include <lustre_sec.h>

#include "ptlrpc_internal.h"

/****************************************
 * bulk encryption page pools      *
 ****************************************/


#define PTRS_PER_PAGE   (PAGE_CACHE_SIZE / sizeof(void *))
#define PAGES_PER_POOL  (PTRS_PER_PAGE)

#define IDLE_IDX_MAX        (100)
#define IDLE_IDX_WEIGHT  (3)

#define CACHE_QUIESCENT_PERIOD  (20)

static struct ptlrpc_enc_page_pool {
        /*
         * constants
         */
        unsigned long    epp_max_pages;   /* maximum pages can hold, const */
        unsigned int     epp_max_pools;   /* number of pools, const */

        /*
         * wait queue in case of not enough free pages.
         */
        wait_queue_head_t      epp_waitq;       /* waiting threads */
        unsigned int     epp_waitqlen;    /* wait queue length */
        unsigned long    epp_pages_short; /* # of pages wanted of in-q users */
        unsigned int     epp_growing:1;   /* during adding pages */

        /*
         * indicating how idle the pools are, from 0 to MAX_IDLE_IDX
         * this is counted based on each time when getting pages from
         * the pools, not based on time. which means in case that system
         * is idled for a while but the idle_idx might still be low if no
         * activities happened in the pools.
         */
        unsigned long    epp_idle_idx;

        /* last shrink time due to mem tight */
        long         epp_last_shrink;
        long         epp_last_access;

        /*
         * in-pool pages bookkeeping
         */
        spinlock_t       epp_lock;         /* protect following fields */
        unsigned long    epp_total_pages; /* total pages in pools */
        unsigned long    epp_free_pages;  /* current pages available */

        /*
         * statistics
         */
        unsigned long    epp_st_max_pages;      /* # of pages ever reached */
        unsigned int     epp_st_grows;    /* # of grows */
        unsigned int     epp_st_grow_fails;     /* # of add pages failures */
        unsigned int     epp_st_shrinks;        /* # of shrinks */
        unsigned long    epp_st_access;  /* # of access */
        unsigned long    epp_st_missings;       /* # of cache missing */
        unsigned long    epp_st_lowfree;        /* lowest free pages reached */
        unsigned int     epp_st_max_wqlen;      /* highest waitqueue length */
        cfs_time_t       epp_st_max_wait;       /* in jeffies */
        /*
         * pointers to pools
         */
        struct page    ***epp_pools;
} page_pools;

/*
 * memory shrinker
 */
const int pools_shrinker_seeks = DEFAULT_SEEKS;
static struct shrinker *pools_shrinker = NULL;


/*
 * /proc/fs/lustre/sptlrpc/encrypt_page_pools
 */
int sptlrpc_proc_enc_pool_seq_show(struct seq_file *m, void *v)
{
        int     rc;

        spin_lock(&page_pools.epp_lock);

        rc = seq_printf(m,
                      "physical pages:    %lu\n"
                      "pages per pool:    %lu\n"
                      "max pages:              %lu\n"
                      "max pools:              %u\n"
                      "total pages:          %lu\n"
                      "total free:            %lu\n"
                      "idle index:            %lu/100\n"
                      "last shrink:          %lds\n"
                      "last access:          %lds\n"
                      "max pages reached:       %lu\n"
                      "grows:              %u\n"
                      "grows failure:      %u\n"
                      "shrinks:          %u\n"
                      "cache access:        %lu\n"
                      "cache missing:      %lu\n"
                      "low free mark:      %lu\n"
                      "max waitqueue depth:     %u\n"
                      "max wait time:      "CFS_TIME_T"/%u\n"
                      ,
                      num_physpages,
                      PAGES_PER_POOL,
                      page_pools.epp_max_pages,
                      page_pools.epp_max_pools,
                      page_pools.epp_total_pages,
                      page_pools.epp_free_pages,
                      page_pools.epp_idle_idx,
                      cfs_time_current_sec() - page_pools.epp_last_shrink,
                      cfs_time_current_sec() - page_pools.epp_last_access,
                      page_pools.epp_st_max_pages,
                      page_pools.epp_st_grows,
                      page_pools.epp_st_grow_fails,
                      page_pools.epp_st_shrinks,
                      page_pools.epp_st_access,
                      page_pools.epp_st_missings,
                      page_pools.epp_st_lowfree,
                      page_pools.epp_st_max_wqlen,
                      page_pools.epp_st_max_wait, HZ
                     );

        spin_unlock(&page_pools.epp_lock);
        return rc;
}

static void enc_pools_release_free_pages(long npages)
{
        int     p_idx, g_idx;
        int     p_idx_max1, p_idx_max2;

        LASSERT(npages > 0);
        LASSERT(npages <= page_pools.epp_free_pages);
        LASSERT(page_pools.epp_free_pages <= page_pools.epp_total_pages);

        /* max pool index before the release */
        p_idx_max2 = (page_pools.epp_total_pages - 1) / PAGES_PER_POOL;

        page_pools.epp_free_pages -= npages;
        page_pools.epp_total_pages -= npages;

        /* max pool index after the release */
        p_idx_max1 = page_pools.epp_total_pages == 0 ? -1 :
                     ((page_pools.epp_total_pages - 1) / PAGES_PER_POOL);

        p_idx = page_pools.epp_free_pages / PAGES_PER_POOL;
        g_idx = page_pools.epp_free_pages % PAGES_PER_POOL;
        LASSERT(page_pools.epp_pools[p_idx]);

        while (npages--) {
                LASSERT(page_pools.epp_pools[p_idx]);
                LASSERT(page_pools.epp_pools[p_idx][g_idx] != NULL);

                __free_page(page_pools.epp_pools[p_idx][g_idx]);
                page_pools.epp_pools[p_idx][g_idx] = NULL;

                if (++g_idx == PAGES_PER_POOL) {
                        p_idx++;
                        g_idx = 0;
                }
        };

        /* free unused pools */
        while (p_idx_max1 < p_idx_max2) {
                LASSERT(page_pools.epp_pools[p_idx_max2]);
                OBD_FREE(page_pools.epp_pools[p_idx_max2], PAGE_CACHE_SIZE);
                page_pools.epp_pools[p_idx_max2] = NULL;
                p_idx_max2--;
        }
}

/*
 * could be called frequently for query (@nr_to_scan == 0).
 * we try to keep at least PTLRPC_MAX_BRW_PAGES pages in the pool.
 */
static int enc_pools_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
{
        if (unlikely(shrink_param(sc, nr_to_scan) != 0)) {
                spin_lock(&page_pools.epp_lock);
                shrink_param(sc, nr_to_scan) = min_t(unsigned long,
                                                   shrink_param(sc, nr_to_scan),
                                                   page_pools.epp_free_pages -
                                                   PTLRPC_MAX_BRW_PAGES);
                if (shrink_param(sc, nr_to_scan) > 0) {
                        enc_pools_release_free_pages(shrink_param(sc,
                                                                  nr_to_scan));
                        CDEBUG(D_SEC, "released %ld pages, %ld left\n",
                               (long)shrink_param(sc, nr_to_scan),
                               page_pools.epp_free_pages);

                        page_pools.epp_st_shrinks++;
                        page_pools.epp_last_shrink = cfs_time_current_sec();
                }
                spin_unlock(&page_pools.epp_lock);
        }

        /*
         * if no pool access for a long time, we consider it's fully idle.
         * a little race here is fine.
         */
        if (unlikely(cfs_time_current_sec() - page_pools.epp_last_access >
                     CACHE_QUIESCENT_PERIOD)) {
                spin_lock(&page_pools.epp_lock);
                page_pools.epp_idle_idx = IDLE_IDX_MAX;
                spin_unlock(&page_pools.epp_lock);
        }

        LASSERT(page_pools.epp_idle_idx <= IDLE_IDX_MAX);
        return max((int)page_pools.epp_free_pages - PTLRPC_MAX_BRW_PAGES, 0) *
                (IDLE_IDX_MAX - page_pools.epp_idle_idx) / IDLE_IDX_MAX;
}

static inline
int npages_to_npools(unsigned long npages)
{
        return (int) ((npages + PAGES_PER_POOL - 1) / PAGES_PER_POOL);
}

/*
 * return how many pages cleaned up.
 */
static unsigned long enc_pools_cleanup(struct page ***pools, int npools)
{
        unsigned long cleaned = 0;
        int        i, j;

        for (i = 0; i < npools; i++) {
                if (pools[i]) {
                        for (j = 0; j < PAGES_PER_POOL; j++) {
                                if (pools[i][j]) {
                                        __free_page(pools[i][j]);
                                        cleaned++;
                                }
                        }
                        OBD_FREE(pools[i], PAGE_CACHE_SIZE);
                        pools[i] = NULL;
                }
        }

        return cleaned;
}

/*
 * merge @npools pointed by @pools which contains @npages new pages
 * into current pools.
 *
 * we have options to avoid most memory copy with some tricks. but we choose
 * the simplest way to avoid complexity. It's not frequently called.
 */
static void enc_pools_insert(struct page ***pools, int npools, int npages)
{
        int     freeslot;
        int     op_idx, np_idx, og_idx, ng_idx;
        int     cur_npools, end_npools;

        LASSERT(npages > 0);
        LASSERT(page_pools.epp_total_pages+npages <= page_pools.epp_max_pages);
        LASSERT(npages_to_npools(npages) == npools);
        LASSERT(page_pools.epp_growing);

        spin_lock(&page_pools.epp_lock);

        /*
         * (1) fill all the free slots of current pools.
         */
        /* free slots are those left by rent pages, and the extra ones with
         * index >= total_pages, locate at the tail of last pool. */
        freeslot = page_pools.epp_total_pages % PAGES_PER_POOL;
        if (freeslot != 0)
                freeslot = PAGES_PER_POOL - freeslot;
        freeslot += page_pools.epp_total_pages - page_pools.epp_free_pages;

        op_idx = page_pools.epp_free_pages / PAGES_PER_POOL;
        og_idx = page_pools.epp_free_pages % PAGES_PER_POOL;
        np_idx = npools - 1;
        ng_idx = (npages - 1) % PAGES_PER_POOL;

        while (freeslot) {
                LASSERT(page_pools.epp_pools[op_idx][og_idx] == NULL);
                LASSERT(pools[np_idx][ng_idx] != NULL);

                page_pools.epp_pools[op_idx][og_idx] = pools[np_idx][ng_idx];
                pools[np_idx][ng_idx] = NULL;

                freeslot--;

                if (++og_idx == PAGES_PER_POOL) {
                        op_idx++;
                        og_idx = 0;
                }
                if (--ng_idx < 0) {
                        if (np_idx == 0)
                                break;
                        np_idx--;
                        ng_idx = PAGES_PER_POOL - 1;
                }
        }

        /*
         * (2) add pools if needed.
         */
        cur_npools = (page_pools.epp_total_pages + PAGES_PER_POOL - 1) /
                     PAGES_PER_POOL;
        end_npools = (page_pools.epp_total_pages + npages + PAGES_PER_POOL -1) /
                     PAGES_PER_POOL;
        LASSERT(end_npools <= page_pools.epp_max_pools);

        np_idx = 0;
        while (cur_npools < end_npools) {
                LASSERT(page_pools.epp_pools[cur_npools] == NULL);
                LASSERT(np_idx < npools);
                LASSERT(pools[np_idx] != NULL);

                page_pools.epp_pools[cur_npools++] = pools[np_idx];
                pools[np_idx++] = NULL;
        }

        page_pools.epp_total_pages += npages;
        page_pools.epp_free_pages += npages;
        page_pools.epp_st_lowfree = page_pools.epp_free_pages;

        if (page_pools.epp_total_pages > page_pools.epp_st_max_pages)
                page_pools.epp_st_max_pages = page_pools.epp_total_pages;

        CDEBUG(D_SEC, "add %d pages to total %lu\n", npages,
               page_pools.epp_total_pages);

        spin_unlock(&page_pools.epp_lock);
}

static int enc_pools_add_pages(int npages)
{
        static DEFINE_MUTEX(add_pages_mutex);
        struct page   ***pools;
        int          npools, alloced = 0;
        int          i, j, rc = -ENOMEM;

        if (npages < PTLRPC_MAX_BRW_PAGES)
                npages = PTLRPC_MAX_BRW_PAGES;

        mutex_lock(&add_pages_mutex);

        if (npages + page_pools.epp_total_pages > page_pools.epp_max_pages)
                npages = page_pools.epp_max_pages - page_pools.epp_total_pages;
        LASSERT(npages > 0);

        page_pools.epp_st_grows++;

        npools = npages_to_npools(npages);
        OBD_ALLOC(pools, npools * sizeof(*pools));
        if (pools == NULL)
                goto out;

        for (i = 0; i < npools; i++) {
                OBD_ALLOC(pools[i], PAGE_CACHE_SIZE);
                if (pools[i] == NULL)
                        goto out_pools;

                for (j = 0; j < PAGES_PER_POOL && alloced < npages; j++) {
                        pools[i][j] = alloc_page(__GFP_IO |
                                                     __GFP_HIGHMEM);
                        if (pools[i][j] == NULL)
                                goto out_pools;

                        alloced++;
                }
        }
        LASSERT(alloced == npages);

        enc_pools_insert(pools, npools, npages);
        CDEBUG(D_SEC, "added %d pages into pools\n", npages);
        rc = 0;

out_pools:
        enc_pools_cleanup(pools, npools);
        OBD_FREE(pools, npools * sizeof(*pools));
out:
        if (rc) {
                page_pools.epp_st_grow_fails++;
                CERROR("Failed to allocate %d enc pages\n", npages);
        }

        mutex_unlock(&add_pages_mutex);
        return rc;
}

static inline void enc_pools_wakeup(void)
{
        LASSERT(spin_is_locked(&page_pools.epp_lock));
        LASSERT(page_pools.epp_waitqlen >= 0);

        if (unlikely(page_pools.epp_waitqlen)) {
                LASSERT(waitqueue_active(&page_pools.epp_waitq));
                wake_up_all(&page_pools.epp_waitq);
        }
}

static int enc_pools_should_grow(int page_needed, long now)
{
        /* don't grow if someone else is growing the pools right now,
         * or the pools has reached its full capacity
         */
        if (page_pools.epp_growing ||
            page_pools.epp_total_pages == page_pools.epp_max_pages)
                return 0;

        /* if total pages is not enough, we need to grow */
        if (page_pools.epp_total_pages < page_needed)
                return 1;

        /*
         * we wanted to return 0 here if there was a shrink just happened
         * moment ago, but this may cause deadlock if both client and ost
         * live on single node.
         */
#if 0
        if (now - page_pools.epp_last_shrink < 2)
                return 0;
#endif

        /*
         * here we perhaps need consider other factors like wait queue
         * length, idle index, etc. ?
         */

        /* grow the pools in any other cases */
        return 1;
}

/*
 * we allocate the requested pages atomically.
 */
int sptlrpc_enc_pool_get_pages(struct ptlrpc_bulk_desc *desc)
{
        wait_queue_t  waitlink;
        unsigned long   this_idle = -1;
        cfs_time_t      tick = 0;
        long        now;
        int          p_idx, g_idx;
        int          i;

        LASSERT(desc->bd_iov_count > 0);
        LASSERT(desc->bd_iov_count <= page_pools.epp_max_pages);

        /* resent bulk, enc iov might have been allocated previously */
        if (desc->bd_enc_iov != NULL)
                return 0;

        OBD_ALLOC(desc->bd_enc_iov,
                  desc->bd_iov_count * sizeof(*desc->bd_enc_iov));
        if (desc->bd_enc_iov == NULL)
                return -ENOMEM;

        spin_lock(&page_pools.epp_lock);

        page_pools.epp_st_access++;
again:
        if (unlikely(page_pools.epp_free_pages < desc->bd_iov_count)) {
                if (tick == 0)
                        tick = cfs_time_current();

                now = cfs_time_current_sec();

                page_pools.epp_st_missings++;
                page_pools.epp_pages_short += desc->bd_iov_count;

                if (enc_pools_should_grow(desc->bd_iov_count, now)) {
                        page_pools.epp_growing = 1;

                        spin_unlock(&page_pools.epp_lock);
                        enc_pools_add_pages(page_pools.epp_pages_short / 2);
                        spin_lock(&page_pools.epp_lock);

                        page_pools.epp_growing = 0;

                        enc_pools_wakeup();
                } else {
                        if (++page_pools.epp_waitqlen >
                            page_pools.epp_st_max_wqlen)
                                page_pools.epp_st_max_wqlen =
                                                page_pools.epp_waitqlen;

                        set_current_state(TASK_UNINTERRUPTIBLE);
                        init_waitqueue_entry_current(&waitlink);
                        add_wait_queue(&page_pools.epp_waitq, &waitlink);

                        spin_unlock(&page_pools.epp_lock);
                        waitq_wait(&waitlink, TASK_UNINTERRUPTIBLE);
                        remove_wait_queue(&page_pools.epp_waitq, &waitlink);
                        LASSERT(page_pools.epp_waitqlen > 0);
                        spin_lock(&page_pools.epp_lock);
                        page_pools.epp_waitqlen--;
                }

                LASSERT(page_pools.epp_pages_short >= desc->bd_iov_count);
                page_pools.epp_pages_short -= desc->bd_iov_count;

                this_idle = 0;
                goto again;
        }

        /* record max wait time */
        if (unlikely(tick != 0)) {
                tick = cfs_time_current() - tick;
                if (tick > page_pools.epp_st_max_wait)
                        page_pools.epp_st_max_wait = tick;
        }

        /* proceed with rest of allocation */
        page_pools.epp_free_pages -= desc->bd_iov_count;

        p_idx = page_pools.epp_free_pages / PAGES_PER_POOL;
        g_idx = page_pools.epp_free_pages % PAGES_PER_POOL;

        for (i = 0; i < desc->bd_iov_count; i++) {
                LASSERT(page_pools.epp_pools[p_idx][g_idx] != NULL);
                desc->bd_enc_iov[i].kiov_page =
                                        page_pools.epp_pools[p_idx][g_idx];
                page_pools.epp_pools[p_idx][g_idx] = NULL;

                if (++g_idx == PAGES_PER_POOL) {
                        p_idx++;
                        g_idx = 0;
                }
        }

        if (page_pools.epp_free_pages < page_pools.epp_st_lowfree)
                page_pools.epp_st_lowfree = page_pools.epp_free_pages;

        /*
         * new idle index = (old * weight + new) / (weight + 1)
         */
        if (this_idle == -1) {
                this_idle = page_pools.epp_free_pages * IDLE_IDX_MAX /
                            page_pools.epp_total_pages;
        }
        page_pools.epp_idle_idx = (page_pools.epp_idle_idx * IDLE_IDX_WEIGHT +
                                   this_idle) /
                                  (IDLE_IDX_WEIGHT + 1);

        page_pools.epp_last_access = cfs_time_current_sec();

        spin_unlock(&page_pools.epp_lock);
        return 0;
}
EXPORT_SYMBOL(sptlrpc_enc_pool_get_pages);

void sptlrpc_enc_pool_put_pages(struct ptlrpc_bulk_desc *desc)
{
        int     p_idx, g_idx;
        int     i;

        if (desc->bd_enc_iov == NULL)
                return;

        LASSERT(desc->bd_iov_count > 0);

        spin_lock(&page_pools.epp_lock);

        p_idx = page_pools.epp_free_pages / PAGES_PER_POOL;
        g_idx = page_pools.epp_free_pages % PAGES_PER_POOL;

        LASSERT(page_pools.epp_free_pages + desc->bd_iov_count <=
                page_pools.epp_total_pages);
        LASSERT(page_pools.epp_pools[p_idx]);

        for (i = 0; i < desc->bd_iov_count; i++) {
                LASSERT(desc->bd_enc_iov[i].kiov_page != NULL);
                LASSERT(g_idx != 0 || page_pools.epp_pools[p_idx]);
                LASSERT(page_pools.epp_pools[p_idx][g_idx] == NULL);

                page_pools.epp_pools[p_idx][g_idx] =
                                        desc->bd_enc_iov[i].kiov_page;

                if (++g_idx == PAGES_PER_POOL) {
                        p_idx++;
                        g_idx = 0;
                }
        }

        page_pools.epp_free_pages += desc->bd_iov_count;

        enc_pools_wakeup();

        spin_unlock(&page_pools.epp_lock);

        OBD_FREE(desc->bd_enc_iov,
                 desc->bd_iov_count * sizeof(*desc->bd_enc_iov));
        desc->bd_enc_iov = NULL;
}
EXPORT_SYMBOL(sptlrpc_enc_pool_put_pages);

/*
 * we don't do much stuff for add_user/del_user anymore, except adding some
 * initial pages in add_user() if current pools are empty, rest would be
 * handled by the pools's self-adaption.
 */
int sptlrpc_enc_pool_add_user(void)
{
        int     need_grow = 0;

        spin_lock(&page_pools.epp_lock);
        if (page_pools.epp_growing == 0 && page_pools.epp_total_pages == 0) {
                page_pools.epp_growing = 1;
                need_grow = 1;
        }
        spin_unlock(&page_pools.epp_lock);

        if (need_grow) {
                enc_pools_add_pages(PTLRPC_MAX_BRW_PAGES +
                                    PTLRPC_MAX_BRW_PAGES);

                spin_lock(&page_pools.epp_lock);
                page_pools.epp_growing = 0;
                enc_pools_wakeup();
                spin_unlock(&page_pools.epp_lock);
        }
        return 0;
}
EXPORT_SYMBOL(sptlrpc_enc_pool_add_user);

int sptlrpc_enc_pool_del_user(void)
{
        return 0;
}
EXPORT_SYMBOL(sptlrpc_enc_pool_del_user);

static inline void enc_pools_alloc(void)
{
        LASSERT(page_pools.epp_max_pools);
        OBD_ALLOC_LARGE(page_pools.epp_pools,
                        page_pools.epp_max_pools *
                        sizeof(*page_pools.epp_pools));
}

static inline void enc_pools_free(void)
{
        LASSERT(page_pools.epp_max_pools);
        LASSERT(page_pools.epp_pools);

        OBD_FREE_LARGE(page_pools.epp_pools,
                       page_pools.epp_max_pools *
                       sizeof(*page_pools.epp_pools));
}

int sptlrpc_enc_pool_init(void)
{
        /*
         * maximum capacity is 1/8 of total physical memory.
         * is the 1/8 a good number?
         */
        page_pools.epp_max_pages = num_physpages / 8;
        page_pools.epp_max_pools = npages_to_npools(page_pools.epp_max_pages);

        init_waitqueue_head(&page_pools.epp_waitq);
        page_pools.epp_waitqlen = 0;
        page_pools.epp_pages_short = 0;

        page_pools.epp_growing = 0;

        page_pools.epp_idle_idx = 0;
        page_pools.epp_last_shrink = cfs_time_current_sec();
        page_pools.epp_last_access = cfs_time_current_sec();

        spin_lock_init(&page_pools.epp_lock);
        page_pools.epp_total_pages = 0;
        page_pools.epp_free_pages = 0;

        page_pools.epp_st_max_pages = 0;
        page_pools.epp_st_grows = 0;
        page_pools.epp_st_grow_fails = 0;
        page_pools.epp_st_shrinks = 0;
        page_pools.epp_st_access = 0;
        page_pools.epp_st_missings = 0;
        page_pools.epp_st_lowfree = 0;
        page_pools.epp_st_max_wqlen = 0;
        page_pools.epp_st_max_wait = 0;

        enc_pools_alloc();
        if (page_pools.epp_pools == NULL)
                return -ENOMEM;

        pools_shrinker = set_shrinker(pools_shrinker_seeks,
                                          enc_pools_shrink);
        if (pools_shrinker == NULL) {
                enc_pools_free();
                return -ENOMEM;
        }

        return 0;
}

void sptlrpc_enc_pool_fini(void)
{
        unsigned long cleaned, npools;

        LASSERT(pools_shrinker);
        LASSERT(page_pools.epp_pools);
        LASSERT(page_pools.epp_total_pages == page_pools.epp_free_pages);

        remove_shrinker(pools_shrinker);

        npools = npages_to_npools(page_pools.epp_total_pages);
        cleaned = enc_pools_cleanup(page_pools.epp_pools, npools);
        LASSERT(cleaned == page_pools.epp_total_pages);

        enc_pools_free();

        if (page_pools.epp_st_access > 0) {
                CDEBUG(D_SEC,
                       "max pages %lu, grows %u, grow fails %u, shrinks %u, "
                       "access %lu, missing %lu, max qlen %u, max wait "
                       CFS_TIME_T"/%d\n",
                       page_pools.epp_st_max_pages, page_pools.epp_st_grows,
                       page_pools.epp_st_grow_fails,
                       page_pools.epp_st_shrinks, page_pools.epp_st_access,
                       page_pools.epp_st_missings, page_pools.epp_st_max_wqlen,
                       page_pools.epp_st_max_wait, HZ);
        }
}


static int cfs_hash_alg_id[] = {
        [BULK_HASH_ALG_NULL]    = CFS_HASH_ALG_NULL,
        [BULK_HASH_ALG_ADLER32] = CFS_HASH_ALG_ADLER32,
        [BULK_HASH_ALG_CRC32]   = CFS_HASH_ALG_CRC32,
        [BULK_HASH_ALG_MD5]     = CFS_HASH_ALG_MD5,
        [BULK_HASH_ALG_SHA1]    = CFS_HASH_ALG_SHA1,
        [BULK_HASH_ALG_SHA256]  = CFS_HASH_ALG_SHA256,
        [BULK_HASH_ALG_SHA384]  = CFS_HASH_ALG_SHA384,
        [BULK_HASH_ALG_SHA512]  = CFS_HASH_ALG_SHA512,
};
const char * sptlrpc_get_hash_name(__u8 hash_alg)
{
        return cfs_crypto_hash_name(cfs_hash_alg_id[hash_alg]);
}
EXPORT_SYMBOL(sptlrpc_get_hash_name);

__u8 sptlrpc_get_hash_alg(const char *algname)
{
        return cfs_crypto_hash_alg(algname);
}
EXPORT_SYMBOL(sptlrpc_get_hash_alg);

int bulk_sec_desc_unpack(struct lustre_msg *msg, int offset, int swabbed)
{
        struct ptlrpc_bulk_sec_desc *bsd;
        int                       size = msg->lm_buflens[offset];

        bsd = lustre_msg_buf(msg, offset, sizeof(*bsd));
        if (bsd == NULL) {
                CERROR("Invalid bulk sec desc: size %d\n", size);
                return -EINVAL;
        }

        if (swabbed) {
                __swab32s(&bsd->bsd_nob);
        }

        if (unlikely(bsd->bsd_version != 0)) {
                CERROR("Unexpected version %u\n", bsd->bsd_version);
                return -EPROTO;
        }

        if (unlikely(bsd->bsd_type >= SPTLRPC_BULK_MAX)) {
                CERROR("Invalid type %u\n", bsd->bsd_type);
                return -EPROTO;
        }

        /* FIXME more sanity check here */

        if (unlikely(bsd->bsd_svc != SPTLRPC_BULK_SVC_NULL &&
                     bsd->bsd_svc != SPTLRPC_BULK_SVC_INTG &&
                     bsd->bsd_svc != SPTLRPC_BULK_SVC_PRIV)) {
                CERROR("Invalid svc %u\n", bsd->bsd_svc);
                return -EPROTO;
        }

        return 0;
}
EXPORT_SYMBOL(bulk_sec_desc_unpack);

int sptlrpc_get_bulk_checksum(struct ptlrpc_bulk_desc *desc, __u8 alg,
                              void *buf, int buflen)
{
        struct cfs_crypto_hash_desc     *hdesc;
        int                             hashsize;
        char                            hashbuf[64];
        unsigned int                    bufsize;
        int                             i, err;

        LASSERT(alg > BULK_HASH_ALG_NULL && alg < BULK_HASH_ALG_MAX);
        LASSERT(buflen >= 4);

        hdesc = cfs_crypto_hash_init(cfs_hash_alg_id[alg], NULL, 0);
        if (IS_ERR(hdesc)) {
                CERROR("Unable to initialize checksum hash %s\n",
                       cfs_crypto_hash_name(cfs_hash_alg_id[alg]));
                return PTR_ERR(hdesc);
        }

        hashsize = cfs_crypto_hash_digestsize(cfs_hash_alg_id[alg]);

        for (i = 0; i < desc->bd_iov_count; i++) {
                cfs_crypto_hash_update_page(hdesc, desc->bd_iov[i].kiov_page,
                                  desc->bd_iov[i].kiov_offset & ~CFS_PAGE_MASK,
                                  desc->bd_iov[i].kiov_len);
        }
        if (hashsize > buflen) {
                bufsize = sizeof(hashbuf);
                err = cfs_crypto_hash_final(hdesc, (unsigned char *)hashbuf,
                                            &bufsize);
                memcpy(buf, hashbuf, buflen);
        } else {
                bufsize = buflen;
                err = cfs_crypto_hash_final(hdesc, (unsigned char *)buf,
                                            &bufsize);
        }

        if (err)
                cfs_crypto_hash_final(hdesc, NULL, NULL);
        return err;
}
EXPORT_SYMBOL(sptlrpc_get_bulk_checksum);