C++ completion_done函数代码示例

/*
 * This is called to asynchronously write the inode associated with this
 * inode log item out to disk. The inode will already have been locked by
 * a successful call to xfs_inode_item_trylock().
 */
STATIC void
xfs_inode_item_push(
	struct xfs_log_item	*lip)
{
	struct xfs_inode_log_item *iip = INODE_ITEM(lip);
	struct xfs_inode	*ip = iip->ili_inode;

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));
	ASSERT(!completion_done(&ip->i_flush));

	/*
	 * Since we were able to lock the inode's flush lock and
	 * we found it on the AIL, the inode must be dirty.  This
	 * is because the inode is removed from the AIL while still
	 * holding the flush lock in xfs_iflush_done().  Thus, if
	 * we found it in the AIL and were able to obtain the flush
	 * lock without sleeping, then there must not have been
	 * anyone in the process of flushing the inode.
	 */
	ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) ||
	       iip->ili_format.ilf_fields != 0);

	/*
	 * Push the inode to it's backing buffer. This will not remove the
	 * inode from the AIL - a further push will be required to trigger a
	 * buffer push. However, this allows all the dirty inodes to be pushed
	 * to the buffer before it is pushed to disk. The buffer IO completion
	 * will pull the inode from the AIL, mark it clean and unlock the flush
	 * lock.
	 */
	(void) xfs_iflush(ip, SYNC_TRYLOCK);
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
}

static ssize_t core_info_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct msm_vidc_core *core = file->private_data;
	int i = 0;
	if (!core) {
		dprintk(VIDC_ERR, "Invalid params, core: %p\n", core);
		return 0;
	}
	INIT_DBG_BUF(dbg_buf);
	write_str(&dbg_buf, "===============================\n");
	write_str(&dbg_buf, "CORE %d: 0x%p\n", core->id, core);
	write_str(&dbg_buf, "===============================\n");
	write_str(&dbg_buf, "state: %d\n", core->state);
	write_str(&dbg_buf, "base addr: 0x%x\n", core->base_addr);
	write_str(&dbg_buf, "register_base: 0x%x\n", core->register_base);
	write_str(&dbg_buf, "register_size: %u\n", core->register_size);
	write_str(&dbg_buf, "irq: %u\n", core->irq);
	for (i = SYS_MSG_START; i < SYS_MSG_END; i++) {
		write_str(&dbg_buf, "completions[%d]: %s\n", i,
			completion_done(&core->completions[SYS_MSG_INDEX(i)]) ?
			"pending" : "done");
	}
	return simple_read_from_buffer(buf, count, ppos,
			dbg_buf.ptr, dbg_buf.filled_size);
}

/*
 * This is called to asynchronously write the inode associated with this
 * inode log item out to disk. The inode will already have been locked by
 * a successful call to xfs_inode_item_trylock().
 */
STATIC void
xfs_inode_item_push(
	xfs_inode_log_item_t	*iip)
{
	xfs_inode_t	*ip;

	ip = iip->ili_inode;

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));
	ASSERT(!completion_done(&ip->i_flush));
	/*
	 * Since we were able to lock the inode's flush lock and
	 * we found it on the AIL, the inode must be dirty.  This
	 * is because the inode is removed from the AIL while still
	 * holding the flush lock in xfs_iflush_done().  Thus, if
	 * we found it in the AIL and were able to obtain the flush
	 * lock without sleeping, then there must not have been
	 * anyone in the process of flushing the inode.
	 */
	ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) ||
	       iip->ili_format.ilf_fields != 0);

	/*
	 * Write out the inode.  The completion routine ('iflush_done') will
	 * pull it from the AIL, mark it clean, unlock the flush lock.
	 */
	(void) xfs_iflush(ip, XFS_IFLUSH_ASYNC);
	xfs_iunlock(ip, XFS_ILOCK_SHARED);

	return;
}

/*
 * This is called when IOP_TRYLOCK returns XFS_ITEM_PUSHBUF to indicate that
 * the dquot is locked by us, but the flush lock isn't. So, here we are
 * going to see if the relevant dquot buffer is incore, waiting on DELWRI.
 * If so, we want to push it out to help us take this item off the AIL as soon
 * as possible.
 *
 * We must not be holding the AIL lock at this point. Calling incore() to
 * search the buffer cache can be a time consuming thing, and AIL lock is a
 * spinlock.
 */
STATIC void
xfs_qm_dquot_logitem_pushbuf(
	struct xfs_log_item	*lip)
{
	struct xfs_dq_logitem	*qlip = DQUOT_ITEM(lip);
	struct xfs_dquot	*dqp = qlip->qli_dquot;
	struct xfs_buf		*bp;

	ASSERT(XFS_DQ_IS_LOCKED(dqp));

	/*
	 * If flushlock isn't locked anymore, chances are that the
	 * inode flush completed and the inode was taken off the AIL.
	 * So, just get out.
	 */
	if (completion_done(&dqp->q_flush) ||
	    !(lip->li_flags & XFS_LI_IN_AIL)) {
		xfs_dqunlock(dqp);
		return;
	}

	bp = xfs_incore(dqp->q_mount->m_ddev_targp, qlip->qli_format.qlf_blkno,
			dqp->q_mount->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK);
	xfs_dqunlock(dqp);
	if (!bp)
		return;
	if (XFS_BUF_ISDELAYWRITE(bp))
		xfs_buf_delwri_promote(bp);
	xfs_buf_relse(bp);
}

/*
 * This gets called by xfs_trans_push_ail(), when IOP_TRYLOCK
 * failed to get the inode flush lock but did get the inode locked SHARED.
 * Here we're trying to see if the inode buffer is incore, and if so whether it's
 * marked delayed write. If that's the case, we'll promote it and that will
 * allow the caller to write the buffer by triggering the xfsbufd to run.
 */
STATIC bool
xfs_inode_item_pushbuf(
	struct xfs_log_item	*lip)
{
	struct xfs_inode_log_item *iip = INODE_ITEM(lip);
	struct xfs_inode	*ip = iip->ili_inode;
	struct xfs_buf		*bp;
	bool			ret = true;

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));

	/*
	 * If a flush is not in progress anymore, chances are that the
	 * inode was taken off the AIL. So, just get out.
	 */
	if (completion_done(&ip->i_flush) ||
	    !(lip->li_flags & XFS_LI_IN_AIL)) {
		xfs_iunlock(ip, XFS_ILOCK_SHARED);
		return true;
	}

	bp = xfs_incore(ip->i_mount->m_ddev_targp, iip->ili_format.ilf_blkno,
			iip->ili_format.ilf_len, XBF_TRYLOCK);

	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	if (!bp)
		return true;
	if (XFS_BUF_ISDELAYWRITE(bp))
		xfs_buf_delwri_promote(bp);
	if (xfs_buf_ispinned(bp))
		ret = false;
	xfs_buf_relse(bp);
	return ret;
}

static void qedf_fcoe_process_vlan_resp(struct qedf_ctx *qedf,
	struct sk_buff *skb)
{
	struct fip_header *fiph;
	struct fip_desc *desc;
	u16 vid = 0;
	ssize_t rlen;
	size_t dlen;

	fiph = (struct fip_header *)(((void *)skb->data) + 2 * ETH_ALEN + 2);

	rlen = ntohs(fiph->fip_dl_len) * 4;
	desc = (struct fip_desc *)(fiph + 1);
	while (rlen > 0) {
		dlen = desc->fip_dlen * FIP_BPW;
		switch (desc->fip_dtype) {
		case FIP_DT_VLAN:
			vid = ntohs(((struct fip_vlan_desc *)desc)->fd_vlan);
			break;
		}
		desc = (struct fip_desc *)((char *)desc + dlen);
		rlen -= dlen;
	}

	QEDF_INFO(&(qedf->dbg_ctx), QEDF_LOG_DISC, "VLAN response, "
		   "vid=0x%x.\n", vid);

	if (vid > 0 && qedf->vlan_id != vid) {
		qedf_set_vlan_id(qedf, vid);

		/* Inform waiter that it's ok to call fcoe_ctlr_link up() */
		if (!completion_done(&qedf->fipvlan_compl))
			complete(&qedf->fipvlan_compl);
	}
}

/*
 * Given the logitem, this writes the corresponding dquot entry to disk
 * asynchronously. This is called with the dquot entry securely locked;
 * we simply get xfs_qm_dqflush() to do the work, and unlock the dquot
 * at the end.
 */
STATIC void
xfs_qm_dquot_logitem_push(
	struct xfs_log_item	*lip)
{
	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
	int			error;

	ASSERT(XFS_DQ_IS_LOCKED(dqp));
	ASSERT(!completion_done(&dqp->q_flush));

	/*
	 * Since we were able to lock the dquot's flush lock and
	 * we found it on the AIL, the dquot must be dirty.  This
	 * is because the dquot is removed from the AIL while still
	 * holding the flush lock in xfs_dqflush_done().  Thus, if
	 * we found it in the AIL and were able to obtain the flush
	 * lock without sleeping, then there must not have been
	 * anyone in the process of flushing the dquot.
	 */
	error = xfs_qm_dqflush(dqp, 0);
	if (error)
		xfs_fs_cmn_err(CE_WARN, dqp->q_mount,
			"xfs_qm_dquot_logitem_push: push error %d on dqp %p",
			error, dqp);
	xfs_dqunlock(dqp);
}

static ssize_t ppi_chr_read(struct file* filp, char __user* buffer, size_t count, loff_t* offset) {
    if(bfin_read_PPI_STATUS() != 0) {
        printk(KERN_WARNING DRIVER_NAME ": PPI error. PPI_STATUS (%d)\n", bfin_read_PPI_STATUS());
        bfin_write_PPI_STATUS(0);
    }

    if(sizeof(current_buffer_pointer) != count) {
        return -EINVAL;
    }

    /* Wait for buffer to fill and pointer to be set */
    if(wait_for_completion_interruptible(&buffer_ready)) {
        return -EINTR;
    }

    /* Check for backlog */
    if(completion_done(&buffer_ready)) {
        printk(KERN_WARNING DRIVER_NAME ": Missed data packet!\n");
    }

    /* Copy value of the pointer to the just filled buffer to the user buffer */
    if(copy_to_user(buffer, &current_buffer_pointer, count)) {
        return -EFAULT;
    }

    /* Reset the completion flag so completions don't pile up */
    INIT_COMPLETION(buffer_ready);

    return 0;
}

static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
{
	unsigned long flags;
	struct scpi_xfer *t, *match = NULL;

	spin_lock_irqsave(&ch->rx_lock, flags);
	if (list_empty(&ch->rx_pending)) {
		spin_unlock_irqrestore(&ch->rx_lock, flags);
		return;
	}

	list_for_each_entry(t, &ch->rx_pending, node)
		if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) {
			list_del(&t->node);
			match = t;
			break;
		}
	/* check if wait_for_completion is in progress or timed-out */
	if (match && !completion_done(&match->done)) {
		struct scpi_shared_mem *mem = ch->rx_payload;

		match->status = le32_to_cpu(mem->status);
		memcpy_fromio(match->rx_buf, mem->payload, CMD_SIZE(cmd));
		complete(&match->done);
	}
	spin_unlock_irqrestore(&ch->rx_lock, flags);
}

static inline bool pending_buffer_requests(struct audio_stream *stream)
{
	int i;
	for (i = 0; i < stream->num_bufs; i++)
		if (!completion_done(&stream->comp[i]))
			return true;
	return false;
}

int sync_wait_on_multiple_events(struct sync_object **events,
				     unsigned count, unsigned timeout,
				     unsigned *index)
{
	unsigned i;
	int status = -EPERM;
	struct completion m_comp;

	init_completion(&m_comp);

	if (SYNC_INFINITE == timeout)
		timeout = MAX_SCHEDULE_TIMEOUT;

	spin_lock_bh(&sync_lock);
	for (i = 0; i < count; i++) {
		if (completion_done(&events[i]->comp)) {
			INIT_COMPLETION(events[i]->comp);
			*index = i;
			spin_unlock_bh(&sync_lock);
			status = 0;
			goto func_end;
		}
	}

	for (i = 0; i < count; i++)
		events[i]->multi_comp = &m_comp;

	spin_unlock_bh(&sync_lock);

	if (!wait_for_completion_interruptible_timeout(&m_comp,
					msecs_to_jiffies(timeout)))
		status = -ETIME;

	spin_lock_bh(&sync_lock);
	for (i = 0; i < count; i++) {
		if (completion_done(&events[i]->comp)) {
			INIT_COMPLETION(events[i]->comp);
			*index = i;
			status = 0;
		}
		events[i]->multi_comp = NULL;
	}
	spin_unlock_bh(&sync_lock);
func_end:
	return status;
}

static UBYTE IicPortBusy(UBYTE Port)
{
	UBYTE Result = 0;

	if (!completion_done(&IicCtrl[Port].message_completion))
		Result = 1;

	return Result;
}

void
xfs_inode_free(
	struct xfs_inode	*ip)
{
	switch (ip->i_d.di_mode & S_IFMT) {
	case S_IFREG:
	case S_IFDIR:
	case S_IFLNK:
		xfs_idestroy_fork(ip, XFS_DATA_FORK);
		break;
	}

	if (ip->i_afp)
		xfs_idestroy_fork(ip, XFS_ATTR_FORK);

	if (ip->i_itemp) {
		/*
		 * Only if we are shutting down the fs will we see an
		 * inode still in the AIL. If it is there, we should remove
		 * it to prevent a use-after-free from occurring.
		 */
		xfs_log_item_t	*lip = &ip->i_itemp->ili_item;
		struct xfs_ail	*ailp = lip->li_ailp;

		ASSERT(((lip->li_flags & XFS_LI_IN_AIL) == 0) ||
				       XFS_FORCED_SHUTDOWN(ip->i_mount));
		if (lip->li_flags & XFS_LI_IN_AIL) {
			spin_lock(&ailp->xa_lock);
			if (lip->li_flags & XFS_LI_IN_AIL)
				xfs_trans_ail_delete(ailp, lip);
			else
				spin_unlock(&ailp->xa_lock);
		}
		xfs_inode_item_destroy(ip);
		ip->i_itemp = NULL;
	}

	/* asserts to verify all state is correct here */
	ASSERT(atomic_read(&ip->i_iocount) == 0);
	ASSERT(atomic_read(&ip->i_pincount) == 0);
	ASSERT(!spin_is_locked(&ip->i_flags_lock));
	ASSERT(completion_done(&ip->i_flush));

	/*
	 * Because we use RCU freeing we need to ensure the inode always
	 * appears to be reclaimed with an invalid inode number when in the
	 * free state. The ip->i_flags_lock provides the barrier against lookup
	 * races.
	 */
	spin_lock(&ip->i_flags_lock);
	ip->i_flags = XFS_IRECLAIM;
	ip->i_ino = 0;
	spin_unlock(&ip->i_flags_lock);

	call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
}

static void bebob_remove(struct fw_unit *unit)
{
	struct snd_bebob *bebob = dev_get_drvdata(&unit->device);

	if (bebob == NULL)
		return;

	/* Awake bus-reset waiters. */
	if (!completion_done(&bebob->bus_reset))
		complete_all(&bebob->bus_reset);

	/* No need to wait for releasing card object in this context. */
	snd_card_free_when_closed(bebob->card);
}

static int __test_mutex(unsigned int flags)
{
#define TIMEOUT (HZ / 16)
	struct test_mutex mtx;
	struct ww_acquire_ctx ctx;
	int ret;

	ww_mutex_init(&mtx.mutex, &ww_class);
	ww_acquire_init(&ctx, &ww_class);

	INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
	init_completion(&mtx.ready);
	init_completion(&mtx.go);
	init_completion(&mtx.done);
	mtx.flags = flags;

	schedule_work(&mtx.work);

	wait_for_completion(&mtx.ready);
	ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
	complete(&mtx.go);
	if (flags & TEST_MTX_SPIN) {
		unsigned long timeout = jiffies + TIMEOUT;

		ret = 0;
		do {
			if (completion_done(&mtx.done)) {
				ret = -EINVAL;
				break;
			}
			cond_resched();
		} while (time_before(jiffies, timeout));
	} else {
		ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
	}
	ww_mutex_unlock(&mtx.mutex);
	ww_acquire_fini(&ctx);

	if (ret) {
		pr_err("%s(flags=%x): mutual exclusion failure\n",
		       __func__, flags);
		ret = -EINVAL;
	}

	flush_work(&mtx.work);
	destroy_work_on_stack(&mtx.work);
	return ret;
#undef TIMEOUT
}