upgrade ppc44x to 2.6.28.2, add basic support for the AMCC Canyonlands

[openwrt.git] / target / linux / generic-2.6 / files / crypto / ocf / crypto.c

/*-
 * Linux port done by David McCullough <david_mccullough@securecomputing.com>
 * Copyright (C) 2006-2007 David McCullough
 * Copyright (C) 2004-2005 Intel Corporation.
 * The license and original author are listed below.
 *
 * Redistribution and use in source and binary forms, with or without
 * Copyright (c) 2002-2006 Sam Leffler.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#if 0
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/opencrypto/crypto.c,v 1.27 2007/03/21 03:42:51 sam Exp $");
#endif

/*
 * Cryptographic Subsystem.
 *
 * This code is derived from the Openbsd Cryptographic Framework (OCF)
 * that has the copyright shown below.  Very little of the original
 * code remains.
 */
/*-
 * The author of this code is Angelos D. Keromytis (angelos@cis.upenn.edu)
 *
 * This code was written by Angelos D. Keromytis in Athens, Greece, in
 * February 2000. Network Security Technologies Inc. (NSTI) kindly
 * supported the development of this code.
 *
 * Copyright (c) 2000, 2001 Angelos D. Keromytis
 *
 * Permission to use, copy, and modify this software with or without fee
 * is hereby granted, provided that this entire notice is included in
 * all source code copies of any software which is or includes a copy or
 * modification of this software.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
 * PURPOSE.
 *
__FBSDID("$FreeBSD: src/sys/opencrypto/crypto.c,v 1.16 2005/01/07 02:29:16 imp Exp $");
 */


#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/version.h>
#include <cryptodev.h>

/*
 * keep track of whether or not we have been initialised, a big
 * issue if we are linked into the kernel and a driver gets started before
 * us
 */
static int crypto_initted = 0;

/*
 * Crypto drivers register themselves by allocating a slot in the
 * crypto_drivers table with crypto_get_driverid() and then registering
 * each algorithm they support with crypto_register() and crypto_kregister().
 */

/*
 * lock on driver table
 * we track its state as spin_is_locked does not do anything on non-SMP boxes
 */
static spinlock_t       crypto_drivers_lock;
static int                      crypto_drivers_locked;          /* for non-SMP boxes */

#define CRYPTO_DRIVER_LOCK() \
                        ({ \
                                spin_lock_irqsave(&crypto_drivers_lock, d_flags); \
                                crypto_drivers_locked = 1; \
                                dprintk("%s,%d: DRIVER_LOCK()\n", __FILE__, __LINE__); \
                         })
#define CRYPTO_DRIVER_UNLOCK() \
                        ({ \
                                dprintk("%s,%d: DRIVER_UNLOCK()\n", __FILE__, __LINE__); \
                                crypto_drivers_locked = 0; \
                                spin_unlock_irqrestore(&crypto_drivers_lock, d_flags); \
                         })
#define CRYPTO_DRIVER_ASSERT() \
                        ({ \
                                if (!crypto_drivers_locked) { \
                                        dprintk("%s,%d: DRIVER_ASSERT!\n", __FILE__, __LINE__); \
                                } \
                         })

/*
 * Crypto device/driver capabilities structure.
 *
 * Synchronization:
 * (d) - protected by CRYPTO_DRIVER_LOCK()
 * (q) - protected by CRYPTO_Q_LOCK()
 * Not tagged fields are read-only.
 */
struct cryptocap {
        device_t        cc_dev;                 /* (d) device/driver */
        u_int32_t       cc_sessions;            /* (d) # of sessions */
        u_int32_t       cc_koperations;         /* (d) # os asym operations */
        /*
         * Largest possible operator length (in bits) for each type of
         * encryption algorithm. XXX not used
         */
        u_int16_t       cc_max_op_len[CRYPTO_ALGORITHM_MAX + 1];
        u_int8_t        cc_alg[CRYPTO_ALGORITHM_MAX + 1];
        u_int8_t        cc_kalg[CRK_ALGORITHM_MAX + 1];

        int             cc_flags;               /* (d) flags */
#define CRYPTOCAP_F_CLEANUP     0x80000000      /* needs resource cleanup */
        int             cc_qblocked;            /* (q) symmetric q blocked */
        int             cc_kqblocked;           /* (q) asymmetric q blocked */
};
static struct cryptocap *crypto_drivers = NULL;
static int crypto_drivers_num = 0;

/*
 * There are two queues for crypto requests; one for symmetric (e.g.
 * cipher) operations and one for asymmetric (e.g. MOD)operations.
 * A single mutex is used to lock access to both queues.  We could
 * have one per-queue but having one simplifies handling of block/unblock
 * operations.
 */
static  int crp_sleep = 0;
static LIST_HEAD(crp_q);                /* request queues */
static LIST_HEAD(crp_kq);

static spinlock_t crypto_q_lock;

int crypto_all_qblocked = 0;  /* protect with Q_LOCK */
module_param(crypto_all_qblocked, int, 0444);
MODULE_PARM_DESC(crypto_all_qblocked, "Are all crypto queues blocked");

int crypto_all_kqblocked = 0; /* protect with Q_LOCK */
module_param(crypto_all_kqblocked, int, 0444);
MODULE_PARM_DESC(crypto_all_kqblocked, "Are all asym crypto queues blocked");

#define CRYPTO_Q_LOCK() \
                        ({ \
                                spin_lock_irqsave(&crypto_q_lock, q_flags); \
                                dprintk("%s,%d: Q_LOCK()\n", __FILE__, __LINE__); \
                         })
#define CRYPTO_Q_UNLOCK() \
                        ({ \
                                dprintk("%s,%d: Q_UNLOCK()\n", __FILE__, __LINE__); \
                                spin_unlock_irqrestore(&crypto_q_lock, q_flags); \
                         })

/*
 * There are two queues for processing completed crypto requests; one
 * for the symmetric and one for the asymmetric ops.  We only need one
 * but have two to avoid type futzing (cryptop vs. cryptkop).  A single
 * mutex is used to lock access to both queues.  Note that this lock
 * must be separate from the lock on request queues to insure driver
 * callbacks don't generate lock order reversals.
 */
static LIST_HEAD(crp_ret_q);            /* callback queues */
static LIST_HEAD(crp_ret_kq);

static spinlock_t crypto_ret_q_lock;
#define CRYPTO_RETQ_LOCK() \
                        ({ \
                                spin_lock_irqsave(&crypto_ret_q_lock, r_flags); \
                                dprintk("%s,%d: RETQ_LOCK\n", __FILE__, __LINE__); \
                         })
#define CRYPTO_RETQ_UNLOCK() \
                        ({ \
                                dprintk("%s,%d: RETQ_UNLOCK\n", __FILE__, __LINE__); \
                                spin_unlock_irqrestore(&crypto_ret_q_lock, r_flags); \
                         })
#define CRYPTO_RETQ_EMPTY()     (list_empty(&crp_ret_q) && list_empty(&crp_ret_kq))

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
static kmem_cache_t *cryptop_zone;
static kmem_cache_t *cryptodesc_zone;
#else
static struct kmem_cache *cryptop_zone;
static struct kmem_cache *cryptodesc_zone;
#endif

#define debug crypto_debug
int crypto_debug = 0;
module_param(crypto_debug, int, 0644);
MODULE_PARM_DESC(crypto_debug, "Enable debug");
EXPORT_SYMBOL(crypto_debug);

/*
 * Maximum number of outstanding crypto requests before we start
 * failing requests.  We need this to prevent DOS when too many
 * requests are arriving for us to keep up.  Otherwise we will
 * run the system out of memory.  Since crypto is slow,  we are
 * usually the bottleneck that needs to say, enough is enough.
 *
 * We cannot print errors when this condition occurs,  we are already too
 * slow,  printing anything will just kill us
 */

static int crypto_q_cnt = 0;
module_param(crypto_q_cnt, int, 0444);
MODULE_PARM_DESC(crypto_q_cnt,
                "Current number of outstanding crypto requests");

static int crypto_q_max = 1000;
module_param(crypto_q_max, int, 0644);
MODULE_PARM_DESC(crypto_q_max,
                "Maximum number of outstanding crypto requests");

#define bootverbose crypto_verbose
static int crypto_verbose = 0;
module_param(crypto_verbose, int, 0644);
MODULE_PARM_DESC(crypto_verbose,
                "Enable verbose crypto startup");

int     crypto_usercrypto = 1;  /* userland may do crypto reqs */
module_param(crypto_usercrypto, int, 0644);
MODULE_PARM_DESC(crypto_usercrypto,
           "Enable/disable user-mode access to crypto support");

int     crypto_userasymcrypto = 1;      /* userland may do asym crypto reqs */
module_param(crypto_userasymcrypto, int, 0644);
MODULE_PARM_DESC(crypto_userasymcrypto,
           "Enable/disable user-mode access to asymmetric crypto support");

int     crypto_devallowsoft = 0;        /* only use hardware crypto */
module_param(crypto_devallowsoft, int, 0644);
MODULE_PARM_DESC(crypto_devallowsoft,
           "Enable/disable use of software crypto support");

static pid_t    cryptoproc = (pid_t) -1;
static struct   completion cryptoproc_exited;
static DECLARE_WAIT_QUEUE_HEAD(cryptoproc_wait);
static pid_t    cryptoretproc = (pid_t) -1;
static struct   completion cryptoretproc_exited;
static DECLARE_WAIT_QUEUE_HEAD(cryptoretproc_wait);

static  int crypto_proc(void *arg);
static  int crypto_ret_proc(void *arg);
static  int crypto_invoke(struct cryptocap *cap, struct cryptop *crp, int hint);
static  int crypto_kinvoke(struct cryptkop *krp, int flags);
static  void crypto_exit(void);
static  int crypto_init(void);

static  struct cryptostats cryptostats;

static struct cryptocap *
crypto_checkdriver(u_int32_t hid)
{
        if (crypto_drivers == NULL)
                return NULL;
        return (hid >= crypto_drivers_num ? NULL : &crypto_drivers[hid]);
}

/*
 * Compare a driver's list of supported algorithms against another
 * list; return non-zero if all algorithms are supported.
 */
static int
driver_suitable(const struct cryptocap *cap, const struct cryptoini *cri)
{
        const struct cryptoini *cr;

        /* See if all the algorithms are supported. */
        for (cr = cri; cr; cr = cr->cri_next)
                if (cap->cc_alg[cr->cri_alg] == 0)
                        return 0;
        return 1;
}

/*
 * Select a driver for a new session that supports the specified
 * algorithms and, optionally, is constrained according to the flags.
 * The algorithm we use here is pretty stupid; just use the
 * first driver that supports all the algorithms we need. If there
 * are multiple drivers we choose the driver with the fewest active
 * sessions.  We prefer hardware-backed drivers to software ones.
 *
 * XXX We need more smarts here (in real life too, but that's
 * XXX another story altogether).
 */
static struct cryptocap *
crypto_select_driver(const struct cryptoini *cri, int flags)
{
        struct cryptocap *cap, *best;
        int match, hid;

        CRYPTO_DRIVER_ASSERT();

        /*
         * Look first for hardware crypto devices if permitted.
         */
        if (flags & CRYPTOCAP_F_HARDWARE)
                match = CRYPTOCAP_F_HARDWARE;
        else
                match = CRYPTOCAP_F_SOFTWARE;
        best = NULL;
again:
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                cap = &crypto_drivers[hid];
                /*
                 * If it's not initialized, is in the process of
                 * going away, or is not appropriate (hardware
                 * or software based on match), then skip.
                 */
                if (cap->cc_dev == NULL ||
                    (cap->cc_flags & CRYPTOCAP_F_CLEANUP) ||
                    (cap->cc_flags & match) == 0)
                        continue;

                /* verify all the algorithms are supported. */
                if (driver_suitable(cap, cri)) {
                        if (best == NULL ||
                            cap->cc_sessions < best->cc_sessions)
                                best = cap;
                }
        }
        if (best != NULL)
                return best;
        if (match == CRYPTOCAP_F_HARDWARE && (flags & CRYPTOCAP_F_SOFTWARE)) {
                /* sort of an Algol 68-style for loop */
                match = CRYPTOCAP_F_SOFTWARE;
                goto again;
        }
        return best;
}

/*
 * Create a new session.  The crid argument specifies a crypto
 * driver to use or constraints on a driver to select (hardware
 * only, software only, either).  Whatever driver is selected
 * must be capable of the requested crypto algorithms.
 */
int
crypto_newsession(u_int64_t *sid, struct cryptoini *cri, int crid)
{
        struct cryptocap *cap;
        u_int32_t hid, lid;
        int err;
        unsigned long d_flags;

        CRYPTO_DRIVER_LOCK();
        if ((crid & (CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE)) == 0) {
                /*
                 * Use specified driver; verify it is capable.
                 */
                cap = crypto_checkdriver(crid);
                if (cap != NULL && !driver_suitable(cap, cri))
                        cap = NULL;
        } else {
                /*
                 * No requested driver; select based on crid flags.
                 */
                cap = crypto_select_driver(cri, crid);
                /*
                 * if NULL then can't do everything in one session.
                 * XXX Fix this. We need to inject a "virtual" session
                 * XXX layer right about here.
                 */
        }
        if (cap != NULL) {
                /* Call the driver initialization routine. */
                hid = cap - crypto_drivers;
                lid = hid;              /* Pass the driver ID. */
                cap->cc_sessions++;
                CRYPTO_DRIVER_UNLOCK();
                err = CRYPTODEV_NEWSESSION(cap->cc_dev, &lid, cri);
                CRYPTO_DRIVER_LOCK();
                if (err == 0) {
                        (*sid) = (cap->cc_flags & 0xff000000)
                               | (hid & 0x00ffffff);
                        (*sid) <<= 32;
                        (*sid) |= (lid & 0xffffffff);
                } else
                        cap->cc_sessions--;
        } else
                err = EINVAL;
        CRYPTO_DRIVER_UNLOCK();
        return err;
}

static void
crypto_remove(struct cryptocap *cap)
{
        CRYPTO_DRIVER_ASSERT();
        if (cap->cc_sessions == 0 && cap->cc_koperations == 0)
                bzero(cap, sizeof(*cap));
}

/*
 * Delete an existing session (or a reserved session on an unregistered
 * driver).
 */
int
crypto_freesession(u_int64_t sid)
{
        struct cryptocap *cap;
        u_int32_t hid;
        int err = 0;
        unsigned long d_flags;

        dprintk("%s()\n", __FUNCTION__);
        CRYPTO_DRIVER_LOCK();

        if (crypto_drivers == NULL) {
                err = EINVAL;
                goto done;
        }

        /* Determine two IDs. */
        hid = CRYPTO_SESID2HID(sid);

        if (hid >= crypto_drivers_num) {
                dprintk("%s - INVALID DRIVER NUM %d\n", __FUNCTION__, hid);
                err = ENOENT;
                goto done;
        }
        cap = &crypto_drivers[hid];

        if (cap->cc_dev) {
                CRYPTO_DRIVER_UNLOCK();
                /* Call the driver cleanup routine, if available, unlocked. */
                err = CRYPTODEV_FREESESSION(cap->cc_dev, sid);
                CRYPTO_DRIVER_LOCK();
        }

        if (cap->cc_sessions)
                cap->cc_sessions--;

        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP)
                crypto_remove(cap);

done:
        CRYPTO_DRIVER_UNLOCK();
        return err;
}

/*
 * Return an unused driver id.  Used by drivers prior to registering
 * support for the algorithms they handle.
 */
int32_t
crypto_get_driverid(device_t dev, int flags)
{
        struct cryptocap *newdrv;
        int i;
        unsigned long d_flags;

        if ((flags & (CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE)) == 0) {
                printf("%s: no flags specified when registering driver\n",
                    device_get_nameunit(dev));
                return -1;
        }

        CRYPTO_DRIVER_LOCK();

        for (i = 0; i < crypto_drivers_num; i++) {
                if (crypto_drivers[i].cc_dev == NULL &&
                    (crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP) == 0) {
                        break;
                }
        }

        /* Out of entries, allocate some more. */
        if (i == crypto_drivers_num) {
                /* Be careful about wrap-around. */
                if (2 * crypto_drivers_num <= crypto_drivers_num) {
                        CRYPTO_DRIVER_UNLOCK();
                        printk("crypto: driver count wraparound!\n");
                        return -1;
                }

                newdrv = kmalloc(2 * crypto_drivers_num * sizeof(struct cryptocap),
                                GFP_KERNEL);
                if (newdrv == NULL) {
                        CRYPTO_DRIVER_UNLOCK();
                        printk("crypto: no space to expand driver table!\n");
                        return -1;
                }

                memcpy(newdrv, crypto_drivers,
                                crypto_drivers_num * sizeof(struct cryptocap));
                memset(&newdrv[crypto_drivers_num], 0,
                                crypto_drivers_num * sizeof(struct cryptocap));

                crypto_drivers_num *= 2;

                kfree(crypto_drivers);
                crypto_drivers = newdrv;
        }

        /* NB: state is zero'd on free */
        crypto_drivers[i].cc_sessions = 1;      /* Mark */
        crypto_drivers[i].cc_dev = dev;
        crypto_drivers[i].cc_flags = flags;
        if (bootverbose)
                printf("crypto: assign %s driver id %u, flags %u\n",
                    device_get_nameunit(dev), i, flags);

        CRYPTO_DRIVER_UNLOCK();

        return i;
}

/*
 * Lookup a driver by name.  We match against the full device
 * name and unit, and against just the name.  The latter gives
 * us a simple widlcarding by device name.  On success return the
 * driver/hardware identifier; otherwise return -1.
 */
int
crypto_find_driver(const char *match)
{
        int i, len = strlen(match);
        unsigned long d_flags;

        CRYPTO_DRIVER_LOCK();
        for (i = 0; i < crypto_drivers_num; i++) {
                device_t dev = crypto_drivers[i].cc_dev;
                if (dev == NULL ||
                    (crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP))
                        continue;
                if (strncmp(match, device_get_nameunit(dev), len) == 0 ||
                    strncmp(match, device_get_name(dev), len) == 0)
                        break;
        }
        CRYPTO_DRIVER_UNLOCK();
        return i < crypto_drivers_num ? i : -1;
}

/*
 * Return the device_t for the specified driver or NULL
 * if the driver identifier is invalid.
 */
device_t
crypto_find_device_byhid(int hid)
{
        struct cryptocap *cap = crypto_checkdriver(hid);
        return cap != NULL ? cap->cc_dev : NULL;
}

/*
 * Return the device/driver capabilities.
 */
int
crypto_getcaps(int hid)
{
        struct cryptocap *cap = crypto_checkdriver(hid);
        return cap != NULL ? cap->cc_flags : 0;
}

/*
 * Register support for a key-related algorithm.  This routine
 * is called once for each algorithm supported a driver.
 */
int
crypto_kregister(u_int32_t driverid, int kalg, u_int32_t flags)
{
        struct cryptocap *cap;
        int err;
        unsigned long d_flags;

        dprintk("%s()\n", __FUNCTION__);
        CRYPTO_DRIVER_LOCK();

        cap = crypto_checkdriver(driverid);
        if (cap != NULL &&
            (CRK_ALGORITM_MIN <= kalg && kalg <= CRK_ALGORITHM_MAX)) {
                /*
                 * XXX Do some performance testing to determine placing.
                 * XXX We probably need an auxiliary data structure that
                 * XXX describes relative performances.
                 */

                cap->cc_kalg[kalg] = flags | CRYPTO_ALG_FLAG_SUPPORTED;
                if (bootverbose)
                        printf("crypto: %s registers key alg %u flags %u\n"
                                , device_get_nameunit(cap->cc_dev)
                                , kalg
                                , flags
                        );
                err = 0;
        } else
                err = EINVAL;

        CRYPTO_DRIVER_UNLOCK();
        return err;
}

/*
 * Register support for a non-key-related algorithm.  This routine
 * is called once for each such algorithm supported by a driver.
 */
int
crypto_register(u_int32_t driverid, int alg, u_int16_t maxoplen,
    u_int32_t flags)
{
        struct cryptocap *cap;
        int err;
        unsigned long d_flags;

        dprintk("%s(id=0x%x, alg=%d, maxoplen=%d, flags=0x%x)\n", __FUNCTION__,
                        driverid, alg, maxoplen, flags);

        CRYPTO_DRIVER_LOCK();

        cap = crypto_checkdriver(driverid);
        /* NB: algorithms are in the range [1..max] */
        if (cap != NULL &&
            (CRYPTO_ALGORITHM_MIN <= alg && alg <= CRYPTO_ALGORITHM_MAX)) {
                /*
                 * XXX Do some performance testing to determine placing.
                 * XXX We probably need an auxiliary data structure that
                 * XXX describes relative performances.
                 */

                cap->cc_alg[alg] = flags | CRYPTO_ALG_FLAG_SUPPORTED;
                cap->cc_max_op_len[alg] = maxoplen;
                if (bootverbose)
                        printf("crypto: %s registers alg %u flags %u maxoplen %u\n"
                                , device_get_nameunit(cap->cc_dev)
                                , alg
                                , flags
                                , maxoplen
                        );
                cap->cc_sessions = 0;           /* Unmark */
                err = 0;
        } else
                err = EINVAL;

        CRYPTO_DRIVER_UNLOCK();
        return err;
}

static void
driver_finis(struct cryptocap *cap)
{
        u_int32_t ses, kops;

        CRYPTO_DRIVER_ASSERT();

        ses = cap->cc_sessions;
        kops = cap->cc_koperations;
        bzero(cap, sizeof(*cap));
        if (ses != 0 || kops != 0) {
                /*
                 * If there are pending sessions,
                 * just mark as invalid.
                 */
                cap->cc_flags |= CRYPTOCAP_F_CLEANUP;
                cap->cc_sessions = ses;
                cap->cc_koperations = kops;
        }
}

/*
 * Unregister a crypto driver. If there are pending sessions using it,
 * leave enough information around so that subsequent calls using those
 * sessions will correctly detect the driver has been unregistered and
 * reroute requests.
 */
int
crypto_unregister(u_int32_t driverid, int alg)
{
        struct cryptocap *cap;
        int i, err;
        unsigned long d_flags;

        dprintk("%s()\n", __FUNCTION__);
        CRYPTO_DRIVER_LOCK();

        cap = crypto_checkdriver(driverid);
        if (cap != NULL &&
            (CRYPTO_ALGORITHM_MIN <= alg && alg <= CRYPTO_ALGORITHM_MAX) &&
            cap->cc_alg[alg] != 0) {
                cap->cc_alg[alg] = 0;
                cap->cc_max_op_len[alg] = 0;

                /* Was this the last algorithm ? */
                for (i = 1; i <= CRYPTO_ALGORITHM_MAX; i++)
                        if (cap->cc_alg[i] != 0)
                                break;

                if (i == CRYPTO_ALGORITHM_MAX + 1)
                        driver_finis(cap);
                err = 0;
        } else
                err = EINVAL;
        CRYPTO_DRIVER_UNLOCK();
        return err;
}

/*
 * Unregister all algorithms associated with a crypto driver.
 * If there are pending sessions using it, leave enough information
 * around so that subsequent calls using those sessions will
 * correctly detect the driver has been unregistered and reroute
 * requests.
 */
int
crypto_unregister_all(u_int32_t driverid)
{
        struct cryptocap *cap;
        int err;
        unsigned long d_flags;

        dprintk("%s()\n", __FUNCTION__);
        CRYPTO_DRIVER_LOCK();
        cap = crypto_checkdriver(driverid);
        if (cap != NULL) {
                driver_finis(cap);
                err = 0;
        } else
                err = EINVAL;
        CRYPTO_DRIVER_UNLOCK();

        return err;
}

/*
 * Clear blockage on a driver.  The what parameter indicates whether
 * the driver is now ready for cryptop's and/or cryptokop's.
 */
int
crypto_unblock(u_int32_t driverid, int what)
{
        struct cryptocap *cap;
        int err;
        unsigned long q_flags;

        CRYPTO_Q_LOCK();
        cap = crypto_checkdriver(driverid);
        if (cap != NULL) {
                if (what & CRYPTO_SYMQ) {
                        cap->cc_qblocked = 0;
                        crypto_all_qblocked = 0;
                }
                if (what & CRYPTO_ASYMQ) {
                        cap->cc_kqblocked = 0;
                        crypto_all_kqblocked = 0;
                }
                if (crp_sleep)
                        wake_up_interruptible(&cryptoproc_wait);
                err = 0;
        } else
                err = EINVAL;
        CRYPTO_Q_UNLOCK(); //DAVIDM should this be a driver lock

        return err;
}

/*
 * Add a crypto request to a queue, to be processed by the kernel thread.
 */
int
crypto_dispatch(struct cryptop *crp)
{
        struct cryptocap *cap;
        int result = -1;
        unsigned long q_flags;

        dprintk("%s()\n", __FUNCTION__);

        cryptostats.cs_ops++;

        CRYPTO_Q_LOCK();
        if (crypto_q_cnt >= crypto_q_max) {
                CRYPTO_Q_UNLOCK();
                cryptostats.cs_drops++;
                return ENOMEM;
        }
        crypto_q_cnt++;

        /*
         * Caller marked the request to be processed immediately; dispatch
         * it directly to the driver unless the driver is currently blocked.
         */
        if ((crp->crp_flags & CRYPTO_F_BATCH) == 0) {
                int hid = CRYPTO_SESID2HID(crp->crp_sid);
                cap = crypto_checkdriver(hid);
                /* Driver cannot disappear when there is an active session. */
                KASSERT(cap != NULL, ("%s: Driver disappeared.", __func__));
                if (!cap->cc_qblocked) {
                        crypto_all_qblocked = 0;
                        crypto_drivers[hid].cc_qblocked = 1;
                        CRYPTO_Q_UNLOCK();
                        result = crypto_invoke(cap, crp, 0);
                        CRYPTO_Q_LOCK();
                        if (result != ERESTART)
                                crypto_drivers[hid].cc_qblocked = 0;
                }
        }
        if (result == ERESTART) {
                /*
                 * The driver ran out of resources, mark the
                 * driver ``blocked'' for cryptop's and put
                 * the request back in the queue.  It would
                 * best to put the request back where we got
                 * it but that's hard so for now we put it
                 * at the front.  This should be ok; putting
                 * it at the end does not work.
                 */
                list_add(&crp->crp_next, &crp_q);
                cryptostats.cs_blocks++;
        } else if (result == -1) {
                TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
        }
        if (crp_sleep)
                wake_up_interruptible(&cryptoproc_wait);
        CRYPTO_Q_UNLOCK();
        return 0;
}

/*
 * Add an asymetric crypto request to a queue,
 * to be processed by the kernel thread.
 */
int
crypto_kdispatch(struct cryptkop *krp)
{
        int error;
        unsigned long q_flags;

        cryptostats.cs_kops++;

        error = crypto_kinvoke(krp, krp->krp_crid);
        if (error == ERESTART) {
                CRYPTO_Q_LOCK();
                TAILQ_INSERT_TAIL(&crp_kq, krp, krp_next);
                if (crp_sleep)
                        wake_up_interruptible(&cryptoproc_wait);
                CRYPTO_Q_UNLOCK();
                error = 0;
        }
        return error;
}

/*
 * Verify a driver is suitable for the specified operation.
 */
static __inline int
kdriver_suitable(const struct cryptocap *cap, const struct cryptkop *krp)
{
        return (cap->cc_kalg[krp->krp_op] & CRYPTO_ALG_FLAG_SUPPORTED) != 0;
}

/*
 * Select a driver for an asym operation.  The driver must
 * support the necessary algorithm.  The caller can constrain
 * which device is selected with the flags parameter.  The
 * algorithm we use here is pretty stupid; just use the first
 * driver that supports the algorithms we need. If there are
 * multiple suitable drivers we choose the driver with the
 * fewest active operations.  We prefer hardware-backed
 * drivers to software ones when either may be used.
 */
static struct cryptocap *
crypto_select_kdriver(const struct cryptkop *krp, int flags)
{
        struct cryptocap *cap, *best, *blocked;
        int match, hid;

        CRYPTO_DRIVER_ASSERT();

        /*
         * Look first for hardware crypto devices if permitted.
         */
        if (flags & CRYPTOCAP_F_HARDWARE)
                match = CRYPTOCAP_F_HARDWARE;
        else
                match = CRYPTOCAP_F_SOFTWARE;
        best = NULL;
        blocked = NULL;
again:
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                cap = &crypto_drivers[hid];
                /*
                 * If it's not initialized, is in the process of
                 * going away, or is not appropriate (hardware
                 * or software based on match), then skip.
                 */
                if (cap->cc_dev == NULL ||
                    (cap->cc_flags & CRYPTOCAP_F_CLEANUP) ||
                    (cap->cc_flags & match) == 0)
                        continue;

                /* verify all the algorithms are supported. */
                if (kdriver_suitable(cap, krp)) {
                        if (best == NULL ||
                            cap->cc_koperations < best->cc_koperations)
                                best = cap;
                }
        }
        if (best != NULL)
                return best;
        if (match == CRYPTOCAP_F_HARDWARE && (flags & CRYPTOCAP_F_SOFTWARE)) {
                /* sort of an Algol 68-style for loop */
                match = CRYPTOCAP_F_SOFTWARE;
                goto again;
        }
        return best;
}

/*
 * Dispatch an assymetric crypto request.
 */
static int
crypto_kinvoke(struct cryptkop *krp, int crid)
{
        struct cryptocap *cap = NULL;
        int error;
        unsigned long d_flags;

        KASSERT(krp != NULL, ("%s: krp == NULL", __func__));
        KASSERT(krp->krp_callback != NULL,
            ("%s: krp->crp_callback == NULL", __func__));

        CRYPTO_DRIVER_LOCK();
        if ((crid & (CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE)) == 0) {
                cap = crypto_checkdriver(crid);
                if (cap != NULL) {
                        /*
                         * Driver present, it must support the necessary
                         * algorithm and, if s/w drivers are excluded,
                         * it must be registered as hardware-backed.
                         */
                        if (!kdriver_suitable(cap, krp) ||
                            (!crypto_devallowsoft &&
                             (cap->cc_flags & CRYPTOCAP_F_HARDWARE) == 0))
                                cap = NULL;
                }
        } else {
                /*
                 * No requested driver; select based on crid flags.
                 */
                if (!crypto_devallowsoft)       /* NB: disallow s/w drivers */
                        crid &= ~CRYPTOCAP_F_SOFTWARE;
                cap = crypto_select_kdriver(krp, crid);
        }
        if (cap != NULL && !cap->cc_kqblocked) {
                krp->krp_hid = cap - crypto_drivers;
                cap->cc_koperations++;
                CRYPTO_DRIVER_UNLOCK();
                error = CRYPTODEV_KPROCESS(cap->cc_dev, krp, 0);
                CRYPTO_DRIVER_LOCK();
                if (error == ERESTART) {
                        cap->cc_koperations--;
                        CRYPTO_DRIVER_UNLOCK();
                        return (error);
                }
                /* return the actual device used */
                krp->krp_crid = krp->krp_hid;
        } else {
                /*
                 * NB: cap is !NULL if device is blocked; in
                 *     that case return ERESTART so the operation
                 *     is resubmitted if possible.
                 */
                error = (cap == NULL) ? ENODEV : ERESTART;
        }
        CRYPTO_DRIVER_UNLOCK();

        if (error) {
                krp->krp_status = error;
                crypto_kdone(krp);
        }
        return 0;
}


/*
 * Dispatch a crypto request to the appropriate crypto devices.
 */
static int
crypto_invoke(struct cryptocap *cap, struct cryptop *crp, int hint)
{
        KASSERT(crp != NULL, ("%s: crp == NULL", __func__));
        KASSERT(crp->crp_callback != NULL,
            ("%s: crp->crp_callback == NULL", __func__));
        KASSERT(crp->crp_desc != NULL, ("%s: crp->crp_desc == NULL", __func__));

        dprintk("%s()\n", __FUNCTION__);

#ifdef CRYPTO_TIMING
        if (crypto_timing)
                crypto_tstat(&cryptostats.cs_invoke, &crp->crp_tstamp);
#endif
        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP) {
                struct cryptodesc *crd;
                u_int64_t nid;

                /*
                 * Driver has unregistered; migrate the session and return
                 * an error to the caller so they'll resubmit the op.
                 *
                 * XXX: What if there are more already queued requests for this
                 *      session?
                 */
                crypto_freesession(crp->crp_sid);

                for (crd = crp->crp_desc; crd->crd_next; crd = crd->crd_next)
                        crd->CRD_INI.cri_next = &(crd->crd_next->CRD_INI);

                /* XXX propagate flags from initial session? */
                if (crypto_newsession(&nid, &(crp->crp_desc->CRD_INI),
                    CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE) == 0)
                        crp->crp_sid = nid;

                crp->crp_etype = EAGAIN;
                crypto_done(crp);
                return 0;
        } else {
                /*
                 * Invoke the driver to process the request.
                 */
                return CRYPTODEV_PROCESS(cap->cc_dev, crp, hint);
        }
}

/*
 * Release a set of crypto descriptors.
 */
void
crypto_freereq(struct cryptop *crp)
{
        struct cryptodesc *crd;

        if (crp == NULL)
                return;

#ifdef DIAGNOSTIC
        {
                struct cryptop *crp2;
                unsigned long q_flags;

                CRYPTO_Q_LOCK();
                TAILQ_FOREACH(crp2, &crp_q, crp_next) {
                        KASSERT(crp2 != crp,
                            ("Freeing cryptop from the crypto queue (%p).",
                            crp));
                }
                CRYPTO_Q_UNLOCK();
                CRYPTO_RETQ_LOCK();
                TAILQ_FOREACH(crp2, &crp_ret_q, crp_next) {
                        KASSERT(crp2 != crp,
                            ("Freeing cryptop from the return queue (%p).",
                            crp));
                }
                CRYPTO_RETQ_UNLOCK();
        }
#endif

        while ((crd = crp->crp_desc) != NULL) {
                crp->crp_desc = crd->crd_next;
                kmem_cache_free(cryptodesc_zone, crd);
        }
        kmem_cache_free(cryptop_zone, crp);
}

/*
 * Acquire a set of crypto descriptors.
 */
struct cryptop *
crypto_getreq(int num)
{
        struct cryptodesc *crd;
        struct cryptop *crp;

        crp = kmem_cache_alloc(cryptop_zone, SLAB_ATOMIC);
        if (crp != NULL) {
                memset(crp, 0, sizeof(*crp));
                INIT_LIST_HEAD(&crp->crp_next);
                init_waitqueue_head(&crp->crp_waitq);
                while (num--) {
                        crd = kmem_cache_alloc(cryptodesc_zone, SLAB_ATOMIC);
                        if (crd == NULL) {
                                crypto_freereq(crp);
                                return NULL;
                        }
                        memset(crd, 0, sizeof(*crd));
                        crd->crd_next = crp->crp_desc;
                        crp->crp_desc = crd;
                }
        }
        return crp;
}

/*
 * Invoke the callback on behalf of the driver.
 */
void
crypto_done(struct cryptop *crp)
{
        unsigned long q_flags;

        dprintk("%s()\n", __FUNCTION__);
        if ((crp->crp_flags & CRYPTO_F_DONE) == 0) {
                crp->crp_flags |= CRYPTO_F_DONE;
                CRYPTO_Q_LOCK();
                crypto_q_cnt--;
                CRYPTO_Q_UNLOCK();
        } else
                printk("crypto: crypto_done op already done, flags 0x%x",
                                crp->crp_flags);
        if (crp->crp_etype != 0)
                cryptostats.cs_errs++;
        /*
         * CBIMM means unconditionally do the callback immediately;
         * CBIFSYNC means do the callback immediately only if the
         * operation was done synchronously.  Both are used to avoid
         * doing extraneous context switches; the latter is mostly
         * used with the software crypto driver.
         */
        if ((crp->crp_flags & CRYPTO_F_CBIMM) ||
            ((crp->crp_flags & CRYPTO_F_CBIFSYNC) &&
             (CRYPTO_SESID2CAPS(crp->crp_sid) & CRYPTOCAP_F_SYNC))) {
                /*
                 * Do the callback directly.  This is ok when the
                 * callback routine does very little (e.g. the
                 * /dev/crypto callback method just does a wakeup).
                 */
                crp->crp_callback(crp);
        } else {
                unsigned long r_flags;
                /*
                 * Normal case; queue the callback for the thread.
                 */
                CRYPTO_RETQ_LOCK();
                if (CRYPTO_RETQ_EMPTY())
                        wake_up_interruptible(&cryptoretproc_wait);/* shared wait channel */
                TAILQ_INSERT_TAIL(&crp_ret_q, crp, crp_next);
                CRYPTO_RETQ_UNLOCK();
        }
}

/*
 * Invoke the callback on behalf of the driver.
 */
void
crypto_kdone(struct cryptkop *krp)
{
        struct cryptocap *cap;
        unsigned long d_flags;

        if ((krp->krp_flags & CRYPTO_KF_DONE) != 0)
                printk("crypto: crypto_kdone op already done, flags 0x%x",
                                krp->krp_flags);
        krp->krp_flags |= CRYPTO_KF_DONE;
        if (krp->krp_status != 0)
                cryptostats.cs_kerrs++;

        CRYPTO_DRIVER_LOCK();
        /* XXX: What if driver is loaded in the meantime? */
        if (krp->krp_hid < crypto_drivers_num) {
                cap = &crypto_drivers[krp->krp_hid];
                cap->cc_koperations--;
                KASSERT(cap->cc_koperations >= 0, ("cc_koperations < 0"));
                if (cap->cc_flags & CRYPTOCAP_F_CLEANUP)
                        crypto_remove(cap);
        }
        CRYPTO_DRIVER_UNLOCK();

        /*
         * CBIMM means unconditionally do the callback immediately;
         * This is used to avoid doing extraneous context switches
         */
        if ((krp->krp_flags & CRYPTO_KF_CBIMM)) {
                /*
                 * Do the callback directly.  This is ok when the
                 * callback routine does very little (e.g. the
                 * /dev/crypto callback method just does a wakeup).
                 */
                krp->krp_callback(krp);
        } else {
                unsigned long r_flags;
                /*
                 * Normal case; queue the callback for the thread.
                 */
                CRYPTO_RETQ_LOCK();
                if (CRYPTO_RETQ_EMPTY())
                        wake_up_interruptible(&cryptoretproc_wait);/* shared wait channel */
                TAILQ_INSERT_TAIL(&crp_ret_kq, krp, krp_next);
                CRYPTO_RETQ_UNLOCK();
        }
}

int
crypto_getfeat(int *featp)
{
        int hid, kalg, feat = 0;
        unsigned long d_flags;

        CRYPTO_DRIVER_LOCK();
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                const struct cryptocap *cap = &crypto_drivers[hid];

                if ((cap->cc_flags & CRYPTOCAP_F_SOFTWARE) &&
                    !crypto_devallowsoft) {
                        continue;
                }
                for (kalg = 0; kalg < CRK_ALGORITHM_MAX; kalg++)
                        if (cap->cc_kalg[kalg] & CRYPTO_ALG_FLAG_SUPPORTED)
                                feat |=  1 << kalg;
        }
        CRYPTO_DRIVER_UNLOCK();
        *featp = feat;
        return (0);
}

/*
 * Crypto thread, dispatches crypto requests.
 */
static int
crypto_proc(void *arg)
{
        struct cryptop *crp, *submit;
        struct cryptkop *krp, *krpp;
        struct cryptocap *cap;
        u_int32_t hid;
        int result, hint;
        unsigned long q_flags;

        ocf_daemonize("crypto");

        CRYPTO_Q_LOCK();
        for (;;) {
                /*
                 * we need to make sure we don't get into a busy loop with nothing
                 * to do,  the two crypto_all_*blocked vars help us find out when
                 * we are all full and can do nothing on any driver or Q.  If so we
                 * wait for an unblock.
                 */
                crypto_all_qblocked  = !list_empty(&crp_q);

                /*
                 * Find the first element in the queue that can be
                 * processed and look-ahead to see if multiple ops
                 * are ready for the same driver.
                 */
                submit = NULL;
                hint = 0;
                list_for_each_entry(crp, &crp_q, crp_next) {
                        hid = CRYPTO_SESID2HID(crp->crp_sid);
                        cap = crypto_checkdriver(hid);
                        /*
                         * Driver cannot disappear when there is an active
                         * session.
                         */
                        KASSERT(cap != NULL, ("%s:%u Driver disappeared.",
                            __func__, __LINE__));
                        if (cap == NULL || cap->cc_dev == NULL) {
                                /* Op needs to be migrated, process it. */
                                if (submit == NULL)
                                        submit = crp;
                                break;
                        }
                        if (!cap->cc_qblocked) {
                                if (submit != NULL) {
                                        /*
                                         * We stop on finding another op,
                                         * regardless whether its for the same
                                         * driver or not.  We could keep
                                         * searching the queue but it might be
                                         * better to just use a per-driver
                                         * queue instead.
                                         */
                                        if (CRYPTO_SESID2HID(submit->crp_sid) == hid)
                                                hint = CRYPTO_HINT_MORE;
                                        break;
                                } else {
                                        submit = crp;
                                        if ((submit->crp_flags & CRYPTO_F_BATCH) == 0)
                                                break;
                                        /* keep scanning for more are q'd */
                                }
                        }
                }
                if (submit != NULL) {
                        hid = CRYPTO_SESID2HID(submit->crp_sid);
                        crypto_all_qblocked = 0;
                        list_del(&submit->crp_next);
                        crypto_drivers[hid].cc_qblocked = 1;
                        cap = crypto_checkdriver(hid);
                        CRYPTO_Q_UNLOCK();
                        KASSERT(cap != NULL, ("%s:%u Driver disappeared.",
                            __func__, __LINE__));
                        result = crypto_invoke(cap, submit, hint);
                        CRYPTO_Q_LOCK();
                        if (result == ERESTART) {
                                /*
                                 * The driver ran out of resources, mark the
                                 * driver ``blocked'' for cryptop's and put
                                 * the request back in the queue.  It would
                                 * best to put the request back where we got
                                 * it but that's hard so for now we put it
                                 * at the front.  This should be ok; putting
                                 * it at the end does not work.
                                 */
                                /* XXX validate sid again? */
                                list_add(&submit->crp_next, &crp_q);
                                cryptostats.cs_blocks++;
                        } else
                                crypto_drivers[hid].cc_qblocked=0;
                }

                crypto_all_kqblocked = !list_empty(&crp_kq);

                /* As above, but for key ops */
                krp = NULL;
                list_for_each_entry(krpp, &crp_kq, krp_next) {
                        cap = crypto_checkdriver(krpp->krp_hid);
                        if (cap == NULL || cap->cc_dev == NULL) {
                                /*
                                 * Operation needs to be migrated, invalidate
                                 * the assigned device so it will reselect a
                                 * new one below.  Propagate the original
                                 * crid selection flags if supplied.
                                 */
                                krp->krp_hid = krp->krp_crid &
                                    (CRYPTOCAP_F_SOFTWARE|CRYPTOCAP_F_HARDWARE);
                                if (krp->krp_hid == 0)
                                        krp->krp_hid =
                                    CRYPTOCAP_F_SOFTWARE|CRYPTOCAP_F_HARDWARE;
                                break;
                        }
                        if (!cap->cc_kqblocked) {
                                krp = krpp;
                                break;
                        }
                }
                if (krp != NULL) {
                        crypto_all_kqblocked = 0;
                        list_del(&krp->krp_next);
                        crypto_drivers[krp->krp_hid].cc_kqblocked = 1;
                        CRYPTO_Q_UNLOCK();
                        result = crypto_kinvoke(krp, krp->krp_hid);
                        CRYPTO_Q_LOCK();
                        if (result == ERESTART) {
                                /*
                                 * The driver ran out of resources, mark the
                                 * driver ``blocked'' for cryptkop's and put
                                 * the request back in the queue.  It would
                                 * best to put the request back where we got
                                 * it but that's hard so for now we put it
                                 * at the front.  This should be ok; putting
                                 * it at the end does not work.
                                 */
                                /* XXX validate sid again? */
                                list_add(&krp->krp_next, &crp_kq);
                                cryptostats.cs_kblocks++;
                        } else
                                crypto_drivers[krp->krp_hid].cc_kqblocked = 0;
                }

                if (submit == NULL && krp == NULL) {
                        /*
                         * Nothing more to be processed.  Sleep until we're
                         * woken because there are more ops to process.
                         * This happens either by submission or by a driver
                         * becoming unblocked and notifying us through
                         * crypto_unblock.  Note that when we wakeup we
                         * start processing each queue again from the
                         * front. It's not clear that it's important to
                         * preserve this ordering since ops may finish
                         * out of order if dispatched to different devices
                         * and some become blocked while others do not.
                         */
                        dprintk("%s - sleeping (qe=%d qb=%d kqe=%d kqb=%d)\n",
                                        __FUNCTION__,
                                        list_empty(&crp_q), crypto_all_qblocked,
                                        list_empty(&crp_kq), crypto_all_kqblocked);
                        CRYPTO_Q_UNLOCK();
                        crp_sleep = 1;
                        wait_event_interruptible(cryptoproc_wait,
                                        !(list_empty(&crp_q) || crypto_all_qblocked) ||
                                        !(list_empty(&crp_kq) || crypto_all_kqblocked) ||
                                        cryptoproc == (pid_t) -1);
                        crp_sleep = 0;
                        if (signal_pending (current)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
                                spin_lock_irq(&current->sigmask_lock);
#endif
                                flush_signals(current);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
                                spin_unlock_irq(&current->sigmask_lock);
#endif
                        }
                        CRYPTO_Q_LOCK();
                        dprintk("%s - awake\n", __FUNCTION__);
                        if (cryptoproc == (pid_t) -1)
                                break;
                        cryptostats.cs_intrs++;
                }
        }
        CRYPTO_Q_UNLOCK();
        complete_and_exit(&cryptoproc_exited, 0);
}

/*
 * Crypto returns thread, does callbacks for processed crypto requests.
 * Callbacks are done here, rather than in the crypto drivers, because
 * callbacks typically are expensive and would slow interrupt handling.
 */
static int
crypto_ret_proc(void *arg)
{
        struct cryptop *crpt;
        struct cryptkop *krpt;
        unsigned long  r_flags;

        ocf_daemonize("crypto_ret");

        CRYPTO_RETQ_LOCK();
        for (;;) {
                /* Harvest return q's for completed ops */
                crpt = NULL;
                if (!list_empty(&crp_ret_q))
                        crpt = list_entry(crp_ret_q.next, typeof(*crpt), crp_next);
                if (crpt != NULL)
                        list_del(&crpt->crp_next);

                krpt = NULL;
                if (!list_empty(&crp_ret_kq))
                        krpt = list_entry(crp_ret_kq.next, typeof(*krpt), krp_next);
                if (krpt != NULL)
                        list_del(&krpt->krp_next);

                if (crpt != NULL || krpt != NULL) {
                        CRYPTO_RETQ_UNLOCK();
                        /*
                         * Run callbacks unlocked.
                         */
                        if (crpt != NULL)
                                crpt->crp_callback(crpt);
                        if (krpt != NULL)
                                krpt->krp_callback(krpt);
                        CRYPTO_RETQ_LOCK();
                } else {
                        /*
                         * Nothing more to be processed.  Sleep until we're
                         * woken because there are more returns to process.
                         */
                        dprintk("%s - sleeping\n", __FUNCTION__);
                        CRYPTO_RETQ_UNLOCK();
                        wait_event_interruptible(cryptoretproc_wait,
                                        cryptoretproc == (pid_t) -1 ||
                                        !list_empty(&crp_ret_q) ||
                                        !list_empty(&crp_ret_kq));
                        if (signal_pending (current)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
                                spin_lock_irq(&current->sigmask_lock);
#endif
                                flush_signals(current);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
                                spin_unlock_irq(&current->sigmask_lock);
#endif
                        }
                        CRYPTO_RETQ_LOCK();
                        dprintk("%s - awake\n", __FUNCTION__);
                        if (cryptoretproc == (pid_t) -1) {
                                dprintk("%s - EXITING!\n", __FUNCTION__);
                                break;
                        }
                        cryptostats.cs_rets++;
                }
        }
        CRYPTO_RETQ_UNLOCK();
        complete_and_exit(&cryptoretproc_exited, 0);
}


#if 0 /* should put this into /proc or something */
static void
db_show_drivers(void)
{
        int hid;

        db_printf("%12s %4s %4s %8s %2s %2s\n"
                , "Device"
                , "Ses"
                , "Kops"
                , "Flags"
                , "QB"
                , "KB"
        );
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                const struct cryptocap *cap = &crypto_drivers[hid];
                if (cap->cc_dev == NULL)
                        continue;
                db_printf("%-12s %4u %4u %08x %2u %2u\n"
                    , device_get_nameunit(cap->cc_dev)
                    , cap->cc_sessions
                    , cap->cc_koperations
                    , cap->cc_flags
                    , cap->cc_qblocked
                    , cap->cc_kqblocked
                );
        }
}

DB_SHOW_COMMAND(crypto, db_show_crypto)
{
        struct cryptop *crp;

        db_show_drivers();
        db_printf("\n");

        db_printf("%4s %8s %4s %4s %4s %4s %8s %8s\n",
            "HID", "Caps", "Ilen", "Olen", "Etype", "Flags",
            "Desc", "Callback");
        TAILQ_FOREACH(crp, &crp_q, crp_next) {
                db_printf("%4u %08x %4u %4u %4u %04x %8p %8p\n"
                    , (int) CRYPTO_SESID2HID(crp->crp_sid)
                    , (int) CRYPTO_SESID2CAPS(crp->crp_sid)
                    , crp->crp_ilen, crp->crp_olen
                    , crp->crp_etype
                    , crp->crp_flags
                    , crp->crp_desc
                    , crp->crp_callback
                );
        }
        if (!TAILQ_EMPTY(&crp_ret_q)) {
                db_printf("\n%4s %4s %4s %8s\n",
                    "HID", "Etype", "Flags", "Callback");
                TAILQ_FOREACH(crp, &crp_ret_q, crp_next) {
                        db_printf("%4u %4u %04x %8p\n"
                            , (int) CRYPTO_SESID2HID(crp->crp_sid)
                            , crp->crp_etype
                            , crp->crp_flags
                            , crp->crp_callback
                        );
                }
        }
}

DB_SHOW_COMMAND(kcrypto, db_show_kcrypto)
{
        struct cryptkop *krp;

        db_show_drivers();
        db_printf("\n");

        db_printf("%4s %5s %4s %4s %8s %4s %8s\n",
            "Op", "Status", "#IP", "#OP", "CRID", "HID", "Callback");
        TAILQ_FOREACH(krp, &crp_kq, krp_next) {
                db_printf("%4u %5u %4u %4u %08x %4u %8p\n"
                    , krp->krp_op
                    , krp->krp_status
                    , krp->krp_iparams, krp->krp_oparams
                    , krp->krp_crid, krp->krp_hid
                    , krp->krp_callback
                );
        }
        if (!TAILQ_EMPTY(&crp_ret_q)) {
                db_printf("%4s %5s %8s %4s %8s\n",
                    "Op", "Status", "CRID", "HID", "Callback");
                TAILQ_FOREACH(krp, &crp_ret_kq, krp_next) {
                        db_printf("%4u %5u %08x %4u %8p\n"
                            , krp->krp_op
                            , krp->krp_status
                            , krp->krp_crid, krp->krp_hid
                            , krp->krp_callback
                        );
                }
        }
}
#endif


static int
crypto_init(void)
{
        int error;

        dprintk("%s(0x%x)\n", __FUNCTION__, (int) crypto_init);

        if (crypto_initted)
                return 0;
        crypto_initted = 1;

        spin_lock_init(&crypto_drivers_lock);
        spin_lock_init(&crypto_q_lock);
        spin_lock_init(&crypto_ret_q_lock);

        cryptop_zone = kmem_cache_create("cryptop", sizeof(struct cryptop),
                                       0, SLAB_HWCACHE_ALIGN, NULL
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
                                       , NULL
#endif
                                        );

        cryptodesc_zone = kmem_cache_create("cryptodesc", sizeof(struct cryptodesc),
                                       0, SLAB_HWCACHE_ALIGN, NULL
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
                                       , NULL
#endif
                                        );

        if (cryptodesc_zone == NULL || cryptop_zone == NULL) {
                printk("crypto: crypto_init cannot setup crypto zones\n");
                error = ENOMEM;
                goto bad;
        }

        crypto_drivers_num = CRYPTO_DRIVERS_INITIAL;
        crypto_drivers = kmalloc(crypto_drivers_num * sizeof(struct cryptocap),
                        GFP_KERNEL);
        if (crypto_drivers == NULL) {
                printk("crypto: crypto_init cannot setup crypto drivers\n");
                error = ENOMEM;
                goto bad;
        }

        memset(crypto_drivers, 0, crypto_drivers_num * sizeof(struct cryptocap));

        init_completion(&cryptoproc_exited);
        init_completion(&cryptoretproc_exited);

        cryptoproc = 0; /* to avoid race condition where proc runs first */
        cryptoproc = kernel_thread(crypto_proc, NULL, CLONE_FS|CLONE_FILES);
        if (cryptoproc < 0) {
                error = cryptoproc;
                printk("crypto: crypto_init cannot start crypto thread; error %d",
                        error);
                goto bad;
        }

        cryptoretproc = 0; /* to avoid race condition where proc runs first */
        cryptoretproc = kernel_thread(crypto_ret_proc, NULL, CLONE_FS|CLONE_FILES);
        if (cryptoretproc < 0) {
                error = cryptoretproc;
                printk("crypto: crypto_init cannot start cryptoret thread; error %d",
                                error);
                goto bad;
        }

        return 0;
bad:
        crypto_exit();
        return error;
}


static void
crypto_exit(void)
{
        pid_t p;
        unsigned long d_flags;

        dprintk("%s()\n", __FUNCTION__);

        /*
         * Terminate any crypto threads.
         */

        CRYPTO_DRIVER_LOCK();
        p = cryptoproc;
        cryptoproc = (pid_t) -1;
        kill_proc(p, SIGTERM, 1);
        wake_up_interruptible(&cryptoproc_wait);
        CRYPTO_DRIVER_UNLOCK();

        wait_for_completion(&cryptoproc_exited);

        CRYPTO_DRIVER_LOCK();
        p = cryptoretproc;
        cryptoretproc = (pid_t) -1;
        kill_proc(p, SIGTERM, 1);
        wake_up_interruptible(&cryptoretproc_wait);
        CRYPTO_DRIVER_UNLOCK();

        wait_for_completion(&cryptoretproc_exited);

        /* XXX flush queues??? */

        /* 
         * Reclaim dynamically allocated resources.
         */
        if (crypto_drivers != NULL)
                kfree(crypto_drivers);

        if (cryptodesc_zone != NULL)
                kmem_cache_destroy(cryptodesc_zone);
        if (cryptop_zone != NULL)
                kmem_cache_destroy(cryptop_zone);
}


EXPORT_SYMBOL(crypto_newsession);
EXPORT_SYMBOL(crypto_freesession);
EXPORT_SYMBOL(crypto_get_driverid);
EXPORT_SYMBOL(crypto_kregister);
EXPORT_SYMBOL(crypto_register);
EXPORT_SYMBOL(crypto_unregister);
EXPORT_SYMBOL(crypto_unregister_all);
EXPORT_SYMBOL(crypto_unblock);
EXPORT_SYMBOL(crypto_dispatch);
EXPORT_SYMBOL(crypto_kdispatch);
EXPORT_SYMBOL(crypto_freereq);
EXPORT_SYMBOL(crypto_getreq);
EXPORT_SYMBOL(crypto_done);
EXPORT_SYMBOL(crypto_kdone);
EXPORT_SYMBOL(crypto_getfeat);
EXPORT_SYMBOL(crypto_userasymcrypto);
EXPORT_SYMBOL(crypto_getcaps);
EXPORT_SYMBOL(crypto_find_driver);
EXPORT_SYMBOL(crypto_find_device_byhid);

module_init(crypto_init);
module_exit(crypto_exit);

MODULE_LICENSE("BSD");
MODULE_AUTHOR("David McCullough <david_mccullough@securecomputing.com>");
MODULE_DESCRIPTION("OCF (OpenBSD Cryptographic Framework)");