diff options
Diffstat (limited to 'drivers/staging/lustre/lnet/lnet/lib-eq.c')
| -rw-r--r-- | drivers/staging/lustre/lnet/lnet/lib-eq.c | 426 |
1 files changed, 0 insertions, 426 deletions
diff --git a/drivers/staging/lustre/lnet/lnet/lib-eq.c b/drivers/staging/lustre/lnet/lnet/lib-eq.c deleted file mode 100644 index ea53b5cb3f72..000000000000 --- a/drivers/staging/lustre/lnet/lnet/lib-eq.c +++ /dev/null @@ -1,426 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * 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-eq.c - * - * Library level Event queue management routines - */ - -#define DEBUG_SUBSYSTEM S_LNET - -#include <linux/lnet/lib-lnet.h> - -/** - * Create an event queue that has room for \a count number of events. - * - * The event queue is circular and older events will be overwritten by new - * ones if they are not removed in time by the user using the functions - * LNetEQGet(), LNetEQWait(), or LNetEQPoll(). It is up to the user to - * determine the appropriate size of the event queue to prevent this loss - * of events. Note that when EQ handler is specified in \a callback, no - * event loss can happen, since the handler is run for each event deposited - * into the EQ. - * - * \param count The number of events to be stored in the event queue. It - * will be rounded up to the next power of two. - * \param callback A handler function that runs when an event is deposited - * into the EQ. The constant value LNET_EQ_HANDLER_NONE can be used to - * indicate that no event handler is desired. - * \param handle On successful return, this location will hold a handle for - * the newly created EQ. - * - * \retval 0 On success. - * \retval -EINVAL If an parameter is not valid. - * \retval -ENOMEM If memory for the EQ can't be allocated. - * - * \see lnet_eq_handler_t for the discussion on EQ handler semantics. - */ -int -LNetEQAlloc(unsigned int count, lnet_eq_handler_t callback, - struct lnet_handle_eq *handle) -{ - struct lnet_eq *eq; - - LASSERT(the_lnet.ln_refcount > 0); - - /* - * We need count to be a power of 2 so that when eq_{enq,deq}_seq - * overflow, they don't skip entries, so the queue has the same - * apparent capacity at all times - */ - if (count) - count = roundup_pow_of_two(count); - - if (callback != LNET_EQ_HANDLER_NONE && count) - CWARN("EQ callback is guaranteed to get every event, do you still want to set eqcount %d for polling event which will have locking overhead? Please contact with developer to confirm\n", count); - - /* - * count can be 0 if only need callback, we can eliminate - * overhead of enqueue event - */ - if (!count && callback == LNET_EQ_HANDLER_NONE) - return -EINVAL; - - eq = kzalloc(sizeof(*eq), GFP_NOFS); - if (!eq) - return -ENOMEM; - - if (count) { - eq->eq_events = kvmalloc_array(count, sizeof(struct lnet_event), - GFP_KERNEL | __GFP_ZERO); - if (!eq->eq_events) - goto failed; - /* - * NB allocator has set all event sequence numbers to 0, - * so all them should be earlier than eq_deq_seq - */ - } - - eq->eq_deq_seq = 1; - eq->eq_enq_seq = 1; - eq->eq_size = count; - eq->eq_callback = callback; - - eq->eq_refs = cfs_percpt_alloc(lnet_cpt_table(), - sizeof(*eq->eq_refs[0])); - if (!eq->eq_refs) - goto failed; - - /* MUST hold both exclusive lnet_res_lock */ - lnet_res_lock(LNET_LOCK_EX); - /* - * NB: hold lnet_eq_wait_lock for EQ link/unlink, so we can do - * both EQ lookup and poll event with only lnet_eq_wait_lock - */ - lnet_eq_wait_lock(); - - lnet_res_lh_initialize(&the_lnet.ln_eq_container, &eq->eq_lh); - list_add(&eq->eq_list, &the_lnet.ln_eq_container.rec_active); - - lnet_eq_wait_unlock(); - lnet_res_unlock(LNET_LOCK_EX); - - lnet_eq2handle(handle, eq); - return 0; - -failed: - kvfree(eq->eq_events); - - if (eq->eq_refs) - cfs_percpt_free(eq->eq_refs); - - kfree(eq); - return -ENOMEM; -} -EXPORT_SYMBOL(LNetEQAlloc); - -/** - * Release the resources associated with an event queue if it's idle; - * otherwise do nothing and it's up to the user to try again. - * - * \param eqh A handle for the event queue to be released. - * - * \retval 0 If the EQ is not in use and freed. - * \retval -ENOENT If \a eqh does not point to a valid EQ. - * \retval -EBUSY If the EQ is still in use by some MDs. - */ -int -LNetEQFree(struct lnet_handle_eq eqh) -{ - struct lnet_eq *eq; - struct lnet_event *events = NULL; - int **refs = NULL; - int *ref; - int rc = 0; - int size = 0; - int i; - - LASSERT(the_lnet.ln_refcount > 0); - - lnet_res_lock(LNET_LOCK_EX); - /* - * NB: hold lnet_eq_wait_lock for EQ link/unlink, so we can do - * both EQ lookup and poll event with only lnet_eq_wait_lock - */ - lnet_eq_wait_lock(); - - eq = lnet_handle2eq(&eqh); - if (!eq) { - rc = -ENOENT; - goto out; - } - - cfs_percpt_for_each(ref, i, eq->eq_refs) { - LASSERT(*ref >= 0); - if (!*ref) - continue; - - CDEBUG(D_NET, "Event equeue (%d: %d) busy on destroy.\n", - i, *ref); - rc = -EBUSY; - goto out; - } - - /* stash for free after lock dropped */ - events = eq->eq_events; - size = eq->eq_size; - refs = eq->eq_refs; - - lnet_res_lh_invalidate(&eq->eq_lh); - list_del(&eq->eq_list); - kfree(eq); - out: - lnet_eq_wait_unlock(); - lnet_res_unlock(LNET_LOCK_EX); - - kvfree(events); - if (refs) - cfs_percpt_free(refs); - - return rc; -} -EXPORT_SYMBOL(LNetEQFree); - -void -lnet_eq_enqueue_event(struct lnet_eq *eq, struct lnet_event *ev) -{ - /* MUST called with resource lock hold but w/o lnet_eq_wait_lock */ - int index; - - if (!eq->eq_size) { - LASSERT(eq->eq_callback != LNET_EQ_HANDLER_NONE); - eq->eq_callback(ev); - return; - } - - lnet_eq_wait_lock(); - ev->sequence = eq->eq_enq_seq++; - - LASSERT(eq->eq_size == LOWEST_BIT_SET(eq->eq_size)); - index = ev->sequence & (eq->eq_size - 1); - - eq->eq_events[index] = *ev; - - if (eq->eq_callback != LNET_EQ_HANDLER_NONE) - eq->eq_callback(ev); - - /* Wake anyone waiting in LNetEQPoll() */ - if (waitqueue_active(&the_lnet.ln_eq_waitq)) - wake_up_all(&the_lnet.ln_eq_waitq); - lnet_eq_wait_unlock(); -} - -static int -lnet_eq_dequeue_event(struct lnet_eq *eq, struct lnet_event *ev) -{ - int new_index = eq->eq_deq_seq & (eq->eq_size - 1); - struct lnet_event *new_event = &eq->eq_events[new_index]; - int rc; - - /* must called with lnet_eq_wait_lock hold */ - if (LNET_SEQ_GT(eq->eq_deq_seq, new_event->sequence)) - return 0; - - /* We've got a new event... */ - *ev = *new_event; - - CDEBUG(D_INFO, "event: %p, sequence: %lu, eq->size: %u\n", - new_event, eq->eq_deq_seq, eq->eq_size); - - /* ...but did it overwrite an event we've not seen yet? */ - if (eq->eq_deq_seq == new_event->sequence) { - rc = 1; - } else { - /* - * don't complain with CERROR: some EQs are sized small - * anyway; if it's important, the caller should complain - */ - CDEBUG(D_NET, "Event Queue Overflow: eq seq %lu ev seq %lu\n", - eq->eq_deq_seq, new_event->sequence); - rc = -EOVERFLOW; - } - - eq->eq_deq_seq = new_event->sequence + 1; - return rc; -} - -/** - * A nonblocking function that can be used to get the next event in an EQ. - * If an event handler is associated with the EQ, the handler will run before - * this function returns successfully. The event is removed from the queue. - * - * \param eventq A handle for the event queue. - * \param event On successful return (1 or -EOVERFLOW), this location will - * hold the next event in the EQ. - * - * \retval 0 No pending event in the EQ. - * \retval 1 Indicates success. - * \retval -ENOENT If \a eventq does not point to a valid EQ. - * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that - * at least one event between this event and the last event obtained from the - * EQ has been dropped due to limited space in the EQ. - */ - -/** - * Block the calling process until there is an event in the EQ. - * If an event handler is associated with the EQ, the handler will run before - * this function returns successfully. This function returns the next event - * in the EQ and removes it from the EQ. - * - * \param eventq A handle for the event queue. - * \param event On successful return (1 or -EOVERFLOW), this location will - * hold the next event in the EQ. - * - * \retval 1 Indicates success. - * \retval -ENOENT If \a eventq does not point to a valid EQ. - * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that - * at least one event between this event and the last event obtained from the - * EQ has been dropped due to limited space in the EQ. - */ - -static int -lnet_eq_wait_locked(int *timeout_ms, long state) -__must_hold(&the_lnet.ln_eq_wait_lock) -{ - int tms = *timeout_ms; - int wait; - wait_queue_entry_t wl; - unsigned long now; - - if (!tms) - return -ENXIO; /* don't want to wait and no new event */ - - init_waitqueue_entry(&wl, current); - set_current_state(state); - add_wait_queue(&the_lnet.ln_eq_waitq, &wl); - - lnet_eq_wait_unlock(); - - if (tms < 0) { - schedule(); - } else { - now = jiffies; - schedule_timeout(msecs_to_jiffies(tms)); - tms -= jiffies_to_msecs(jiffies - now); - if (tms < 0) /* no more wait but may have new event */ - tms = 0; - } - - wait = tms; /* might need to call here again */ - *timeout_ms = tms; - - lnet_eq_wait_lock(); - remove_wait_queue(&the_lnet.ln_eq_waitq, &wl); - - return wait; -} - -/** - * Block the calling process until there's an event from a set of EQs or - * timeout happens. - * - * If an event handler is associated with the EQ, the handler will run before - * this function returns successfully, in which case the corresponding event - * is consumed. - * - * LNetEQPoll() provides a timeout to allow applications to poll, block for a - * fixed period, or block indefinitely. - * - * \param eventqs,neq An array of EQ handles, and size of the array. - * \param timeout_ms Time in milliseconds to wait for an event to occur on - * one of the EQs. The constant LNET_TIME_FOREVER can be used to indicate an - * infinite timeout. - * \param interruptible, if true, use TASK_INTERRUPTIBLE, else TASK_NOLOAD - * \param event,which On successful return (1 or -EOVERFLOW), \a event will - * hold the next event in the EQs, and \a which will contain the index of the - * EQ from which the event was taken. - * - * \retval 0 No pending event in the EQs after timeout. - * \retval 1 Indicates success. - * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that - * at least one event between this event and the last event obtained from the - * EQ indicated by \a which has been dropped due to limited space in the EQ. - * \retval -ENOENT If there's an invalid handle in \a eventqs. - */ -int -LNetEQPoll(struct lnet_handle_eq *eventqs, int neq, int timeout_ms, - int interruptible, - struct lnet_event *event, int *which) -{ - int wait = 1; - int rc; - int i; - - LASSERT(the_lnet.ln_refcount > 0); - - if (neq < 1) - return -ENOENT; - - lnet_eq_wait_lock(); - - for (;;) { - for (i = 0; i < neq; i++) { - struct lnet_eq *eq = lnet_handle2eq(&eventqs[i]); - - if (!eq) { - lnet_eq_wait_unlock(); - return -ENOENT; - } - - rc = lnet_eq_dequeue_event(eq, event); - if (rc) { - lnet_eq_wait_unlock(); - *which = i; - return rc; - } - } - - if (!wait) - break; - - /* - * return value of lnet_eq_wait_locked: - * -1 : did nothing and it's sure no new event - * 1 : sleep inside and wait until new event - * 0 : don't want to wait anymore, but might have new event - * so need to call dequeue again - */ - wait = lnet_eq_wait_locked(&timeout_ms, - interruptible ? TASK_INTERRUPTIBLE - : TASK_NOLOAD); - if (wait < 0) /* no new event */ - break; - } - - lnet_eq_wait_unlock(); - return 0; -} |