/*
 * 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.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/lnet/lib-md.c
 *
 * Memory Descriptor management routines
 */

#define DEBUG_SUBSYSTEM S_LNET

#include <linux/lnet/lib-lnet.h>

/* must be called with lnet_res_lock held */
void
lnet_md_unlink(struct lnet_libmd *md)
{
        if (!(md->md_flags & LNET_MD_FLAG_ZOMBIE)) {
                /* first unlink attempt... */
                struct lnet_me *me = md->md_me;

                md->md_flags |= LNET_MD_FLAG_ZOMBIE;

                /*
                 * Disassociate from ME (if any),
                 * and unlink it if it was created
                 * with LNET_UNLINK
                 */
                if (me) {
                        /* detach MD from portal */
                        lnet_ptl_detach_md(me, md);
                        if (me->me_unlink == LNET_UNLINK)
                                lnet_me_unlink(me);
                }

                /* ensure all future handle lookups fail */
                lnet_res_lh_invalidate(&md->md_lh);
        }

        if (md->md_refcount) {
                CDEBUG(D_NET, "Queueing unlink of md %p\n", md);
                return;
        }

        CDEBUG(D_NET, "Unlinking md %p\n", md);

        if (md->md_eq) {
                int cpt = lnet_cpt_of_cookie(md->md_lh.lh_cookie);

                LASSERT(*md->md_eq->eq_refs[cpt] > 0);
                (*md->md_eq->eq_refs[cpt])--;
        }

        LASSERT(!list_empty(&md->md_list));
        list_del_init(&md->md_list);
        lnet_md_free(md);
}

static int
lnet_md_build(struct lnet_libmd *lmd, struct lnet_md *umd, int unlink)
{
        int i;
        unsigned int niov;
        int total_length = 0;

        lmd->md_me = NULL;
        lmd->md_start = umd->start;
        lmd->md_offset = 0;
        lmd->md_max_size = umd->max_size;
        lmd->md_options = umd->options;
        lmd->md_user_ptr = umd->user_ptr;
        lmd->md_eq = NULL;
        lmd->md_threshold = umd->threshold;
        lmd->md_refcount = 0;
        lmd->md_flags = (unlink == LNET_UNLINK) ? LNET_MD_FLAG_AUTO_UNLINK : 0;

        if (umd->options & LNET_MD_IOVEC) {
                if (umd->options & LNET_MD_KIOV) /* Can't specify both */
                        return -EINVAL;

                niov = umd->length;
                lmd->md_niov = umd->length;
                memcpy(lmd->md_iov.iov, umd->start,
                       niov * sizeof(lmd->md_iov.iov[0]));

                for (i = 0; i < (int)niov; i++) {
                        /* We take the base address on trust */
                        /* invalid length */
                        if (lmd->md_iov.iov[i].iov_len <= 0)
                                return -EINVAL;

                        total_length += lmd->md_iov.iov[i].iov_len;
                }

                lmd->md_length = total_length;

                if ((umd->options & LNET_MD_MAX_SIZE) && /* use max size */
                    (umd->max_size < 0 ||
                     umd->max_size > total_length)) /* illegal max_size */
                        return -EINVAL;

        } else if (umd->options & LNET_MD_KIOV) {
                niov = umd->length;
                lmd->md_niov = umd->length;
                memcpy(lmd->md_iov.kiov, umd->start,
                       niov * sizeof(lmd->md_iov.kiov[0]));

                for (i = 0; i < (int)niov; i++) {
                        /* We take the page pointer on trust */
                        if (lmd->md_iov.kiov[i].bv_offset +
                            lmd->md_iov.kiov[i].bv_len > PAGE_SIZE)
                                return -EINVAL; /* invalid length */

                        total_length += lmd->md_iov.kiov[i].bv_len;
                }

                lmd->md_length = total_length;

                if ((umd->options & LNET_MD_MAX_SIZE) && /* max size used */
                    (umd->max_size < 0 ||
                     umd->max_size > total_length)) /* illegal max_size */
                        return -EINVAL;
        } else {   /* contiguous */
                lmd->md_length = umd->length;
                niov = 1;
                lmd->md_niov = 1;
                lmd->md_iov.iov[0].iov_base = umd->start;
                lmd->md_iov.iov[0].iov_len = umd->length;

                if ((umd->options & LNET_MD_MAX_SIZE) && /* max size used */
                    (umd->max_size < 0 ||
                     umd->max_size > (int)umd->length)) /* illegal max_size */
                        return -EINVAL;
        }

        return 0;
}

/* must be called with resource lock held */
static int
lnet_md_link(struct lnet_libmd *md, struct lnet_handle_eq eq_handle, int cpt)
{
        struct lnet_res_container *container = the_lnet.ln_md_containers[cpt];

        /*
         * NB we are passed an allocated, but inactive md.
         * if we return success, caller may lnet_md_unlink() it.
         * otherwise caller may only lnet_md_free() it.
         */
        /*
         * This implementation doesn't know how to create START events or
         * disable END events.  Best to LASSERT our caller is compliant so
         * we find out quickly...
         */
        /*
         * TODO - reevaluate what should be here in light of
         * the removal of the start and end events
         * maybe there we shouldn't even allow LNET_EQ_NONE!)
         * LASSERT(!eq);
         */
        if (!LNetEQHandleIsInvalid(eq_handle)) {
                md->md_eq = lnet_handle2eq(&eq_handle);

                if (!md->md_eq)
                        return -ENOENT;

                (*md->md_eq->eq_refs[cpt])++;
        }

        lnet_res_lh_initialize(container, &md->md_lh);

        LASSERT(list_empty(&md->md_list));
        list_add(&md->md_list, &container->rec_active);

        return 0;
}

/* must be called with lnet_res_lock held */
void
lnet_md_deconstruct(struct lnet_libmd *lmd, struct lnet_md *umd)
{
        /* NB this doesn't copy out all the iov entries so when a
         * discontiguous MD is copied out, the target gets to know the
         * original iov pointer (in start) and the number of entries it had
         * and that's all.
         */
        umd->start = lmd->md_start;
        umd->length = !(lmd->md_options &
                      (LNET_MD_IOVEC | LNET_MD_KIOV)) ?
                      lmd->md_length : lmd->md_niov;
        umd->threshold = lmd->md_threshold;
        umd->max_size = lmd->md_max_size;
        umd->options = lmd->md_options;
        umd->user_ptr = lmd->md_user_ptr;
        lnet_eq2handle(&umd->eq_handle, lmd->md_eq);
}

static int
lnet_md_validate(struct lnet_md *umd)
{
        if (!umd->start && umd->length) {
                CERROR("MD start pointer can not be NULL with length %u\n",
                       umd->length);
                return -EINVAL;
        }

        if ((umd->options & (LNET_MD_KIOV | LNET_MD_IOVEC)) &&
            umd->length > LNET_MAX_IOV) {
                CERROR("Invalid option: too many fragments %u, %d max\n",
                       umd->length, LNET_MAX_IOV);
                return -EINVAL;
        }

        return 0;
}

/**
 * Create a memory descriptor and attach it to a ME
 *
 * \param meh A handle for a ME to associate the new MD with.
 * \param umd Provides initial values for the user-visible parts of a MD.
 * Other than its use for initialization, there is no linkage between this
 * structure and the MD maintained by the LNet.
 * \param unlink A flag to indicate whether the MD is automatically unlinked
 * when it becomes inactive, either because the operation threshold drops to
 * zero or because the available memory becomes less than \a umd.max_size.
 * (Note that the check for unlinking a MD only occurs after the completion
 * of a successful operation on the MD.) The value LNET_UNLINK enables auto
 * unlinking; the value LNET_RETAIN disables it.
 * \param handle On successful returns, a handle to the newly created MD is
 * saved here. This handle can be used later in LNetMDUnlink().
 *
 * \retval 0       On success.
 * \retval -EINVAL If \a umd is not valid.
 * \retval -ENOMEM If new MD cannot be allocated.
 * \retval -ENOENT Either \a meh or \a umd.eq_handle does not point to a
 * valid object. Note that it's OK to supply a NULL \a umd.eq_handle by
 * calling LNetInvalidateHandle() on it.
 * \retval -EBUSY  If the ME pointed to by \a meh is already associated with
 * a MD.
 */
int
LNetMDAttach(struct lnet_handle_me meh, struct lnet_md umd,
             enum lnet_unlink unlink, struct lnet_handle_md *handle)
{
        LIST_HEAD(matches);
        LIST_HEAD(drops);
        struct lnet_me *me;
        struct lnet_libmd *md;
        int cpt;
        int rc;

        LASSERT(the_lnet.ln_refcount > 0);

        if (lnet_md_validate(&umd))
                return -EINVAL;

        if (!(umd.options & (LNET_MD_OP_GET | LNET_MD_OP_PUT))) {
                CERROR("Invalid option: no MD_OP set\n");
                return -EINVAL;
        }

        md = lnet_md_alloc(&umd);
        if (!md)
                return -ENOMEM;

        rc = lnet_md_build(md, &umd, unlink);
        if (rc)
                goto out_free;

        cpt = lnet_cpt_of_cookie(meh.cookie);

        lnet_res_lock(cpt);

        me = lnet_handle2me(&meh);
        if (!me)
                rc = -ENOENT;
        else if (me->me_md)
                rc = -EBUSY;
        else
                rc = lnet_md_link(md, umd.eq_handle, cpt);

        if (rc)
                goto out_unlock;

        /*
         * attach this MD to portal of ME and check if it matches any
         * blocked msgs on this portal
         */
        lnet_ptl_attach_md(me, md, &matches, &drops);

        lnet_md2handle(handle, md);

        lnet_res_unlock(cpt);

        lnet_drop_delayed_msg_list(&drops, "Bad match");
        lnet_recv_delayed_msg_list(&matches);

        return 0;

out_unlock:
        lnet_res_unlock(cpt);
out_free:
        lnet_md_free(md);
        return rc;
}
EXPORT_SYMBOL(LNetMDAttach);

/**
 * Create a "free floating" memory descriptor - a MD that is not associated
 * with a ME. Such MDs are usually used in LNetPut() and LNetGet() operations.
 *
 * \param umd,unlink See the discussion for LNetMDAttach().
 * \param handle On successful returns, a handle to the newly created MD is
 * saved here. This handle can be used later in LNetMDUnlink(), LNetPut(),
 * and LNetGet() operations.
 *
 * \retval 0       On success.
 * \retval -EINVAL If \a umd is not valid.
 * \retval -ENOMEM If new MD cannot be allocated.
 * \retval -ENOENT \a umd.eq_handle does not point to a valid EQ. Note that
 * it's OK to supply a NULL \a umd.eq_handle by calling
 * LNetInvalidateHandle() on it.
 */
int
LNetMDBind(struct lnet_md umd, enum lnet_unlink unlink,
           struct lnet_handle_md *handle)
{
        struct lnet_libmd *md;
        int cpt;
        int rc;

        LASSERT(the_lnet.ln_refcount > 0);

        if (lnet_md_validate(&umd))
                return -EINVAL;

        if ((umd.options & (LNET_MD_OP_GET | LNET_MD_OP_PUT))) {
                CERROR("Invalid option: GET|PUT illegal on active MDs\n");
                return -EINVAL;
        }

        md = lnet_md_alloc(&umd);
        if (!md)
                return -ENOMEM;

        rc = lnet_md_build(md, &umd, unlink);
        if (rc)
                goto out_free;

        cpt = lnet_res_lock_current();

        rc = lnet_md_link(md, umd.eq_handle, cpt);
        if (rc)
                goto out_unlock;

        lnet_md2handle(handle, md);

        lnet_res_unlock(cpt);
        return 0;

out_unlock:
        lnet_res_unlock(cpt);
out_free:
        lnet_md_free(md);

        return rc;
}
EXPORT_SYMBOL(LNetMDBind);

/**
 * Unlink the memory descriptor from any ME it may be linked to and release
 * the internal resources associated with it. As a result, active messages
 * associated with the MD may get aborted.
 *
 * This function does not free the memory region associated with the MD;
 * i.e., the memory the user allocated for this MD. If the ME associated with
 * this MD is not NULL and was created with auto unlink enabled, the ME is
 * unlinked as well (see LNetMEAttach()).
 *
 * Explicitly unlinking a MD via this function call has the same behavior as
 * a MD that has been automatically unlinked, except that no LNET_EVENT_UNLINK
 * is generated in the latter case.
 *
 * An unlinked event can be reported in two ways:
 * - If there's no pending operations on the MD, it's unlinked immediately
 *   and an LNET_EVENT_UNLINK event is logged before this function returns.
 * - Otherwise, the MD is only marked for deletion when this function
 *   returns, and the unlinked event will be piggybacked on the event of
 *   the completion of the last operation by setting the unlinked field of
 *   the event. No dedicated LNET_EVENT_UNLINK event is generated.
 *
 * Note that in both cases the unlinked field of the event is always set; no
 * more event will happen on the MD after such an event is logged.
 *
 * \param mdh A handle for the MD to be unlinked.
 *
 * \retval 0       On success.
 * \retval -ENOENT If \a mdh does not point to a valid MD object.
 */
int
LNetMDUnlink(struct lnet_handle_md mdh)
{
        struct lnet_event ev;
        struct lnet_libmd *md;
        int cpt;

        LASSERT(the_lnet.ln_refcount > 0);

        cpt = lnet_cpt_of_cookie(mdh.cookie);
        lnet_res_lock(cpt);

        md = lnet_handle2md(&mdh);
        if (!md) {
                lnet_res_unlock(cpt);
                return -ENOENT;
        }

        md->md_flags |= LNET_MD_FLAG_ABORTED;
        /*
         * If the MD is busy, lnet_md_unlink just marks it for deletion, and
         * when the LND is done, the completion event flags that the MD was
         * unlinked.  Otherwise, we enqueue an event now...
         */
        if (md->md_eq && !md->md_refcount) {
                lnet_build_unlink_event(md, &ev);
                lnet_eq_enqueue_event(md->md_eq, &ev);
        }

        lnet_md_unlink(md);

        lnet_res_unlock(cpt);
        return 0;
}
EXPORT_SYMBOL(LNetMDUnlink);