C++ write_unlock_irq函数代码示例

/*-------------------------------------------------------------------------
 *  bproc_masq_wait
 */
int masq_wait(pid_t pid, int options, struct siginfo *infop,
	      unsigned int * stat_addr, struct rusage * ru) {
    int result, lpid, status;
    struct bproc_krequest_t *req;
    struct bproc_rsyscall_msg_t *msg;
    struct bproc_wait_resp_t *resp_msg;
    struct task_struct *child;

    /* XXX to be 100% semantically correct, we need to verify_area
     * here on stat_addr and ru here... */
    req = bpr_rsyscall1(BPROC_SYS_WAIT);
    if (!req){
	printk("bproc: masq: sys_wait: out of memory.\n");
	return -ENOMEM;
    }
    msg = (struct bproc_rsyscall_msg_t *) bproc_msg(req);
    msg->arg[0] = pid;
    msg->arg[1] = options;

    if (bpr_rsyscall2(BPROC_MASQ_MASTER(current), req, 1) != 0) {
	bproc_put_req(req);
	return -EIO;
    }

    resp_msg = bproc_msg(req->response);

    result = resp_msg->hdr.result;
    status = resp_msg->status;
    if (stat_addr) put_user(status, stat_addr);
    if (ru) {
	/* Only a few elements of the rusage structure are provided by
	 * Linux.  Also, convert the times back to the HZ
	 * representation. */
	struct rusage ru_tmp;
	memset(&ru_tmp, 0, sizeof(ru_tmp));
	ru_tmp.ru_utime.tv_sec  =  resp_msg->utime/HZ;
	ru_tmp.ru_utime.tv_usec = (resp_msg->utime*(1000000/HZ))%1000000;
	ru_tmp.ru_stime.tv_sec  =  resp_msg->stime/HZ;
	ru_tmp.ru_stime.tv_usec = (resp_msg->stime*(1000000/HZ))%1000000;
	ru_tmp.ru_minflt        =  resp_msg->minflt;
	ru_tmp.ru_majflt        =  resp_msg->majflt;
	ru_tmp.ru_nswap         =  resp_msg->nswap;
	copy_to_user(ru, &ru_tmp, sizeof(ru_tmp));
    }
    bproc_put_req(req);

    if (result > 0 && (status & 0xff) != 0x7f) {
	/* It's possible that the process we waited on was actually
	 * local.  We need to make sure and get it out of this process
	 * tree too.  If it's not, we need to down the non local child
	 * count by one... */
	write_lock_irq(&tasklist_lock);
	child = masq_find_task_by_pid(BPROC_MASQ_MASTER(current), result);
	if (child)
	    lpid = child->pid;
	else {
	    lpid = 0;
	    current->bproc.nlchild--;
	}
	write_unlock_irq(&tasklist_lock);
	if (lpid) {
	    /* Do all of this as a kernel call to avoid re-entering
	     * this whole mess... */
	    set_bit(BPROC_FLAG_KCALL, &current->bproc.flag);
	    if (k_wait4(lpid, options & ~WNOHANG, NULL, NULL, NULL) == -1) {
		printk(KERN_ERR "bproc: masq: local wait failed on %d (%d)\n",
		       lpid, result);
#if 0
		/* This probably isn't correct.  If we fail to wait,
		 * that probably means that somebody else picked it
		 * up. */
		write_lock_irq(&tasklist_lock);
		current->bproc.nlchild--;
		write_unlock_irq(&tasklist_lock);
#endif
	    }
	}
    }
    return result;
}

//.........这里部分代码省略.........
			while (i < 4 && w7[i] == hp_sdc.r7[i])
				i++;

			if (i < 4) {
				hp_sdc_status_out8(HP_SDC_CMD_SET_D0 + i);
				hp_sdc.wi = 0x70 + i;
				goto finish;
			}

			idx++;
			if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAREG)
				goto actdone;

			curr->idx = idx;
			act &= ~HP_SDC_ACT_DATAREG;
			break;
		}

		hp_sdc_data_out8(w7[hp_sdc.wi - 0x70]);
		hp_sdc.r7[hp_sdc.wi - 0x70] = w7[hp_sdc.wi - 0x70];
		hp_sdc.wi++; /* write index register autoincrements */
		{
			int i = 0;

			while ((i < 4) && w7[i] == hp_sdc.r7[i])
				i++;
			if (i >= 4) {
				curr->idx = idx + 1;
				if ((act & HP_SDC_ACT_DURING) ==
				    HP_SDC_ACT_DATAREG)
					goto actdone;
			}
		}
		goto finish;
	}
	/* We don't go any further in the command if there is a pending read,
	   because we don't want interleaved results. */
	read_lock_irq(&hp_sdc.rtq_lock);
	if (hp_sdc.rcurr >= 0) {
		read_unlock_irq(&hp_sdc.rtq_lock);
		goto finish;
	}
	read_unlock_irq(&hp_sdc.rtq_lock);


	if (act & HP_SDC_ACT_POSTCMD) {
		uint8_t postcmd;

		/* curr->idx should == idx at this point. */
		postcmd = curr->seq[idx];
		curr->idx++;
		if (act & HP_SDC_ACT_DATAIN) {

			/* Start a new read */
			hp_sdc.rqty = curr->seq[curr->idx];
			do_gettimeofday(&hp_sdc.rtv);
			curr->idx++;
			/* Still need to lock here in case of spurious irq. */
			write_lock_irq(&hp_sdc.rtq_lock);
			hp_sdc.rcurr = curridx;
			write_unlock_irq(&hp_sdc.rtq_lock);
			hp_sdc_status_out8(postcmd);
			goto finish;
		}
		hp_sdc_status_out8(postcmd);
		goto actdone;
	}

 actdone:
	if (act & HP_SDC_ACT_SEMAPHORE)
		up(curr->act.semaphore);
	else if (act & HP_SDC_ACT_CALLBACK)
		curr->act.irqhook(0,NULL,0,0);

	if (curr->idx >= curr->endidx) { /* This transaction is over. */
		if (act & HP_SDC_ACT_DEALLOC)
			kfree(curr);
		hp_sdc.tq[curridx] = NULL;
	} else {
		curr->actidx = idx + 1;
		curr->idx = idx + 2;
	}
	/* Interleave outbound data between the transactions. */
	hp_sdc.wcurr++;
	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
		hp_sdc.wcurr = 0;

 finish:
	/* If by some quirk IBF has cleared and our ISR has run to
	   see that that has happened, do it all again. */
	if (!hp_sdc.ibf && limit++ < 20)
		goto anew;

 done:
	if (hp_sdc.wcurr >= 0)
		tasklet_schedule(&hp_sdc.task);
	write_unlock(&hp_sdc.lock);

	return 0;
}

static void vcc_remove_socket(struct sock *sk)
{
	write_lock_irq(&vcc_sklist_lock);
	sk_del_node_init(sk);
	write_unlock_irq(&vcc_sklist_lock);
}

/**
 * zfcp_adapter_enqueue - enqueue a new adapter to the list
 * @ccw_device: pointer to the struct cc_device
 *
 * Returns:	0             if a new adapter was successfully enqueued
 *		-ENOMEM       if alloc failed
 * Enqueues an adapter at the end of the adapter list in the driver data.
 * All adapter internal structures are set up.
 * Proc-fs entries are also created.
 * locks:	config_sema must be held to serialise changes to the adapter list
 */
int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
{
	struct zfcp_adapter *adapter;

	/*
	 * Note: It is safe to release the list_lock, as any list changes
	 * are protected by the config_sema, which must be held to get here
	 */

	adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
	if (!adapter)
		return -ENOMEM;

	ccw_device->handler = NULL;
	adapter->ccw_device = ccw_device;
	atomic_set(&adapter->refcount, 0);

	if (zfcp_qdio_allocate(adapter))
		goto qdio_allocate_failed;

	if (zfcp_allocate_low_mem_buffers(adapter))
		goto failed_low_mem_buffers;

	if (zfcp_reqlist_alloc(adapter))
		goto failed_low_mem_buffers;

	if (zfcp_adapter_debug_register(adapter))
		goto debug_register_failed;

	init_waitqueue_head(&adapter->remove_wq);
	init_waitqueue_head(&adapter->erp_thread_wqh);
	init_waitqueue_head(&adapter->erp_done_wqh);

	INIT_LIST_HEAD(&adapter->port_list_head);
	INIT_LIST_HEAD(&adapter->port_remove_lh);
	INIT_LIST_HEAD(&adapter->erp_ready_head);
	INIT_LIST_HEAD(&adapter->erp_running_head);

	spin_lock_init(&adapter->req_list_lock);

	spin_lock_init(&adapter->hba_dbf_lock);
	spin_lock_init(&adapter->san_dbf_lock);
	spin_lock_init(&adapter->scsi_dbf_lock);
	spin_lock_init(&adapter->rec_dbf_lock);
	spin_lock_init(&adapter->req_q.lock);

	rwlock_init(&adapter->erp_lock);
	rwlock_init(&adapter->abort_lock);

	sema_init(&adapter->erp_ready_sem, 0);

	INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
	INIT_WORK(&adapter->scan_work, _zfcp_scan_ports_later);

	/* mark adapter unusable as long as sysfs registration is not complete */
	atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);

	dev_set_drvdata(&ccw_device->dev, adapter);

	if (sysfs_create_group(&ccw_device->dev.kobj,
			       &zfcp_sysfs_adapter_attrs))
		goto sysfs_failed;

	adapter->generic_services.parent = &adapter->ccw_device->dev;
	adapter->generic_services.release = zfcp_dummy_release;
	snprintf(adapter->generic_services.bus_id, BUS_ID_SIZE,
		 "generic_services");

	if (device_register(&adapter->generic_services))
		goto generic_services_failed;

	write_lock_irq(&zfcp_data.config_lock);
	atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
	list_add_tail(&adapter->list, &zfcp_data.adapter_list_head);
	write_unlock_irq(&zfcp_data.config_lock);

	zfcp_data.adapters++;

	zfcp_nameserver_enqueue(adapter);

	return 0;

generic_services_failed:
	sysfs_remove_group(&ccw_device->dev.kobj,
			   &zfcp_sysfs_adapter_attrs);
sysfs_failed:
	zfcp_adapter_debug_unregister(adapter);
debug_register_failed:
	dev_set_drvdata(&ccw_device->dev, NULL);
//.........这里部分代码省略.........

static void ib_cache_update(struct ib_device *device,
                            u8                port)
{
    struct ib_port_attr       *tprops = NULL;
    struct ib_pkey_cache      *pkey_cache = NULL, *old_pkey_cache;
    struct ib_gid_cache       *gid_cache = NULL, *old_gid_cache;
    int                        i;
    int                        ret;

    tprops = kmalloc(sizeof *tprops, GFP_KERNEL);
    if (!tprops)
        return;

    ret = ib_query_port(device, port, tprops);
    if (ret) {
        printk(KERN_WARNING "ib_query_port failed (%d) for %s\n",
               ret, device->name);
        goto err;
    }

    pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len *
                         sizeof *pkey_cache->table, GFP_KERNEL);
    if (!pkey_cache)
        goto err;

    pkey_cache->table_len = tprops->pkey_tbl_len;

    gid_cache = kmalloc(sizeof *gid_cache + tprops->gid_tbl_len *
                        sizeof *gid_cache->table, GFP_KERNEL);
    if (!gid_cache)
        goto err;

    gid_cache->table_len = tprops->gid_tbl_len;

    for (i = 0; i < pkey_cache->table_len; ++i) {
        ret = ib_query_pkey(device, port, i, pkey_cache->table + i);
        if (ret) {
            printk(KERN_WARNING "ib_query_pkey failed (%d) for %s (index %d)\n",
                   ret, device->name, i);
            goto err;
        }
    }

    for (i = 0; i < gid_cache->table_len; ++i) {
        ret = ib_query_gid(device, port, i, gid_cache->table + i);
        if (ret) {
            printk(KERN_WARNING "ib_query_gid failed (%d) for %s (index %d)\n",
                   ret, device->name, i);
            goto err;
        }
    }

    write_lock_irq(&device->cache.lock);

    old_pkey_cache = device->cache.pkey_cache[port - start_port(device)];
    old_gid_cache  = device->cache.gid_cache [port - start_port(device)];

    device->cache.pkey_cache[port - start_port(device)] = pkey_cache;
    device->cache.gid_cache [port - start_port(device)] = gid_cache;

    device->cache.lmc_cache[port - start_port(device)] = tprops->lmc;

    write_unlock_irq(&device->cache.lock);

    kfree(old_pkey_cache);
    kfree(old_gid_cache);
    kfree(tprops);
    return;

err:
    kfree(pkey_cache);
    kfree(gid_cache);
    kfree(tprops);
}

asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
{
	struct task_struct *p;
	int err = -EINVAL;

	if (!pid)
		pid = current->pid;
	if (!pgid)
		pgid = pid;
	if (pgid < 0)
		return -EINVAL;

	/* From this point forward we keep holding onto the tasklist lock
	 * so that our parent does not change from under us. -DaveM
	 */
	write_lock_irq(&tasklist_lock);

	err = -ESRCH;
	p = find_task_by_pid(pid);
	if (!p)
		goto out;

	err = -EINVAL;
	if (!thread_group_leader(p))
		goto out;

	if (p->parent == current || p->real_parent == current) {
		err = -EPERM;
		if (p->signal->session != current->signal->session)
			goto out;
		err = -EACCES;
		if (p->did_exec)
			goto out;
	} else {
		err = -ESRCH;
		if (p != current)
			goto out;
	}

	err = -EPERM;
	if (p->signal->leader)
		goto out;

	if (pgid != pid) {
		struct task_struct *p;

		do_each_task_pid(pgid, PIDTYPE_PGID, p) {
			if (p->signal->session == current->signal->session)
				goto ok_pgid;
		} while_each_task_pid(pgid, PIDTYPE_PGID, p);
		goto out;
	}

ok_pgid:
	err = security_task_setpgid(p, pgid);
	if (err)
		goto out;

	if (process_group(p) != pgid) {
		detach_pid(p, PIDTYPE_PGID);
		p->signal->pgrp = pgid;
		attach_pid(p, PIDTYPE_PGID, pgid);
	}

	err = 0;
out:
	/* All paths lead to here, thus we are safe. -DaveM */
	write_unlock_irq(&tasklist_lock);
	return err;
}

//.........这里部分代码省略.........
	}

	pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len *
			     sizeof *pkey_cache->entry, GFP_KERNEL);
	if (!pkey_cache)
		goto err;

	pkey_cache->table_len = 0;

	gid_cache = kmalloc(sizeof *gid_cache + tprops->gid_tbl_len *
			    sizeof *gid_cache->entry, GFP_KERNEL);
	if (!gid_cache)
		goto err;

	gid_cache->table_len = 0;

	for (i = 0, j = 0; i < tprops->pkey_tbl_len; ++i) {
		ret = ib_query_pkey(device, port, i, &pkey);
		if (ret) {
			printk(KERN_WARNING "ib_query_pkey failed (%d) for %s (index %d)\n",
			       ret, device->name, i);
			goto err;
		}
		/* pkey 0xffff must be the default pkeyand 0x0000 must be the invalid
		 * pkey per IBTA spec */
		if (pkey) {
			pkey_cache->entry[j].index = i;
			pkey_cache->entry[j++].pkey = pkey;
		}
	}
	pkey_cache->table_len = j;

	memset(&empty_gid, 0, sizeof empty_gid);
	for (i = 0, j = 0; i < tprops->gid_tbl_len; ++i) {
		ret = ib_query_gid(device, port, i, &gid);
		if (ret) {
			printk(KERN_WARNING "ib_query_gid failed (%d) for %s (index %d)\n",
			       ret, device->name, i);
			goto err;
		}
		/* if the lower 8 bytes the device GID entry is all 0,
		 * our entry is a blank, invalid entry...
		 * depending on device, the upper 8 bytes might or might
		 * not be prefilled with a valid subnet prefix, so
		 * don't rely on them for determining a valid gid
		 * entry
		 */
		if (memcmp(&gid + 8, &empty_gid + 8, sizeof gid - 8)) {
			gid_cache->entry[j].index = i;
			gid_cache->entry[j++].gid = gid;
		}
	}
	gid_cache->table_len = j;

	old_pkey_cache = pkey_cache;
	pkey_cache = kmalloc(sizeof *pkey_cache + old_pkey_cache->table_len *
			     sizeof *pkey_cache->entry, GFP_KERNEL);
	if (!pkey_cache)
		pkey_cache = old_pkey_cache;
	else {
		pkey_cache->table_len = old_pkey_cache->table_len;
		memcpy(&pkey_cache->entry[0], &old_pkey_cache->entry[0],
		       pkey_cache->table_len * sizeof *pkey_cache->entry);
		kfree(old_pkey_cache);
	}

	old_gid_cache = gid_cache;
	gid_cache = kmalloc(sizeof *gid_cache + old_gid_cache->table_len *
			    sizeof *gid_cache->entry, GFP_KERNEL);
	if (!gid_cache)
		gid_cache = old_gid_cache;
	else {
		gid_cache->table_len = old_gid_cache->table_len;
		memcpy(&gid_cache->entry[0], &old_gid_cache->entry[0],
		       gid_cache->table_len * sizeof *gid_cache->entry);
		kfree(old_gid_cache);
	}

	write_lock_irq(&device->cache.lock);

	old_pkey_cache = device->cache.pkey_cache[port - start_port(device)];
	old_gid_cache  = device->cache.gid_cache [port - start_port(device)];

	device->cache.pkey_cache[port - start_port(device)] = pkey_cache;
	device->cache.gid_cache [port - start_port(device)] = gid_cache;

	device->cache.lmc_cache[port - start_port(device)] = tprops->lmc;

	write_unlock_irq(&device->cache.lock);

	kfree(old_pkey_cache);
	kfree(old_gid_cache);
	kfree(tprops);
	return;

err:
	kfree(pkey_cache);
	kfree(gid_cache);
	kfree(tprops);
}

//.........这里部分代码省略.........
	else
		p->exit_signal = (clone_flags & CSIGNAL);

	p->pdeath_signal = 0;
	p->exit_state = 0;

	p->nr_dirtied = 0;
	p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
	p->dirty_paused_when = 0;

	p->group_leader = p;
	INIT_LIST_HEAD(&p->thread_group);

	cgroup_fork_callbacks(p);
	cgroup_callbacks_done = 1;

	
	write_lock_irq(&tasklist_lock);

	
	if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
		p->real_parent = current->real_parent;
		p->parent_exec_id = current->parent_exec_id;
	} else {
		p->real_parent = current;
		p->parent_exec_id = current->self_exec_id;
	}

	spin_lock(&current->sighand->siglock);

	recalc_sigpending();
	if (signal_pending(current)) {
		spin_unlock(&current->sighand->siglock);
		write_unlock_irq(&tasklist_lock);
		retval = -ERESTARTNOINTR;
		goto bad_fork_free_pid;
	}

	if (clone_flags & CLONE_THREAD) {
		current->signal->nr_threads++;
		atomic_inc(&current->signal->live);
		atomic_inc(&current->signal->sigcnt);
		p->group_leader = current->group_leader;
		list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
	}

	if (likely(p->pid)) {
		ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);

		if (thread_group_leader(p)) {
			if (is_child_reaper(pid))
				p->nsproxy->pid_ns->child_reaper = p;

			p->signal->leader_pid = pid;
			p->signal->tty = tty_kref_get(current->signal->tty);
			attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
			attach_pid(p, PIDTYPE_SID, task_session(current));
			list_add_tail(&p->sibling, &p->real_parent->children);
			list_add_tail_rcu(&p->tasks, &init_task.tasks);
			__this_cpu_inc(process_counts);
		}
		attach_pid(p, PIDTYPE_PID, pid);
		nr_threads++;
	}

	total_forks++;

/**
 * zfcp_unit_enqueue - enqueue unit to unit list of a port.
 * @port: pointer to port where unit is added
 * @fcp_lun: FCP LUN of unit to be enqueued
 * Returns: pointer to enqueued unit on success, ERR_PTR on error
 * Locks: config_mutex must be held to serialize changes to the unit list
 *
 * Sets up some unit internal structures and creates sysfs entry.
 */
struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, u64 fcp_lun)
{
	struct zfcp_unit *unit;

	read_lock_irq(&zfcp_data.config_lock);
	if (zfcp_get_unit_by_lun(port, fcp_lun)) {
		read_unlock_irq(&zfcp_data.config_lock);
		return ERR_PTR(-EINVAL);
	}
	read_unlock_irq(&zfcp_data.config_lock);

	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
	if (!unit)
		return ERR_PTR(-ENOMEM);

	atomic_set(&unit->refcount, 0);
	init_waitqueue_head(&unit->remove_wq);
	INIT_WORK(&unit->scsi_work, zfcp_scsi_scan_work);

	unit->port = port;
	unit->fcp_lun = fcp_lun;

	if (dev_set_name(&unit->sysfs_device, "0x%016llx",
			 (unsigned long long) fcp_lun)) {
		kfree(unit);
		return ERR_PTR(-ENOMEM);
	}
	unit->sysfs_device.parent = &port->sysfs_device;
	unit->sysfs_device.release = zfcp_sysfs_unit_release;
	dev_set_drvdata(&unit->sysfs_device, unit);

	/* mark unit unusable as long as sysfs registration is not complete */
	atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);

	spin_lock_init(&unit->latencies.lock);
	unit->latencies.write.channel.min = 0xFFFFFFFF;
	unit->latencies.write.fabric.min = 0xFFFFFFFF;
	unit->latencies.read.channel.min = 0xFFFFFFFF;
	unit->latencies.read.fabric.min = 0xFFFFFFFF;
	unit->latencies.cmd.channel.min = 0xFFFFFFFF;
	unit->latencies.cmd.fabric.min = 0xFFFFFFFF;

	if (device_register(&unit->sysfs_device)) {
		put_device(&unit->sysfs_device);
		return ERR_PTR(-EINVAL);
	}

	if (sysfs_create_group(&unit->sysfs_device.kobj,
			       &zfcp_sysfs_unit_attrs)) {
		device_unregister(&unit->sysfs_device);
		return ERR_PTR(-EINVAL);
	}

	zfcp_unit_get(unit);

	write_lock_irq(&zfcp_data.config_lock);
	list_add_tail(&unit->list, &port->unit_list_head);
	atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
	atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);

	write_unlock_irq(&zfcp_data.config_lock);

	zfcp_port_get(port);

	return unit;
}

long sys_ptrace(long request, pid_t pid, long addr, long data)
{
	struct task_struct *child;
	long ret;

	lock_kernel();
	ret = -EPERM;
	if (request == PTRACE_TRACEME) {
		/* are we already being traced? */
		if (current->ptrace & PT_PTRACED)
			goto out;
		/* set the ptrace bit in the process flags. */
		current->ptrace |= PT_PTRACED;
		ret = 0;
		goto out;
	}

	ret = -ESRCH;
	read_lock(&tasklist_lock);
	child = find_task_by_pid(pid);
	if (child)
		get_task_struct(child);
	read_unlock(&tasklist_lock);
	if (!child)
		goto out;
	ret = -EPERM;
	if (pid == 1)		/* no messing around with init! */
		goto out_tsk;

	if (request == PTRACE_ATTACH) {
		if (child == current)
			goto out_tsk;
		if ((!child->dumpable ||
		    (current->uid != child->euid) ||
		    (current->uid != child->suid) ||
		    (current->uid != child->uid) ||
	 	    (current->gid != child->egid) ||
	 	    (current->gid != child->sgid) ||
	 	    (!cap_issubset(child->cap_permitted, current->cap_permitted)) ||
	 	    (current->gid != child->gid)) && !capable(CAP_SYS_PTRACE))
			goto out_tsk;
		/* the same process cannot be attached many times */
		if (child->ptrace & PT_PTRACED)
			goto out_tsk;
		child->ptrace |= PT_PTRACED;
		if (child->p_pptr != current) {
			unsigned long flags;

			write_lock_irqsave(&tasklist_lock, flags);
			REMOVE_LINKS(child);
			child->p_pptr = current;
			SET_LINKS(child);
			write_unlock_irqrestore(&tasklist_lock, flags);
		}
		send_sig(SIGSTOP, child, 1);
		ret = 0;
		goto out_tsk;
	}
	ret = -ESRCH;
	if (!(child->ptrace & PT_PTRACED))
		goto out_tsk;
	if (child->state != TASK_STOPPED) {
		if (request != PTRACE_KILL)
			goto out_tsk;
	}
	if (child->p_pptr != current)
		goto out_tsk;

	switch (request) {
	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
	case PTRACE_PEEKDATA: {
		unsigned long tmp;
		int copied;

		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
		ret = -EIO;
		if (copied != sizeof(tmp))
			goto out_tsk;
		ret = put_user(tmp,(unsigned long *) data);
		goto out_tsk;
	}

	/* when I and D space are separate, this will have to be fixed. */
	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA:
		ret = 0;
		if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
			goto out_tsk;
		ret = -EIO;
		goto out_tsk;

	/* Read the word at location addr in the USER area.  This will need
	   to change when the kernel no longer saves all regs on a syscall. */
	case PTRACE_PEEKUSR: {
		unsigned long tmp;

		ret = -EIO;
		if ((addr & 3) || (unsigned long) addr >= sizeof(struct pt_regs))
			goto out_tsk;

//.........这里部分代码省略.........

static int ptrace_attach(struct task_struct *task)
{
	bool wait_trap = false;
	int retval;

	audit_ptrace(task);

	retval = -EPERM;
	if (unlikely(task->flags & PF_KTHREAD))
		goto out;
	if (same_thread_group(task, current))
		goto out;

	/*
	 * Protect exec's credential calculations against our interference;
	 * interference; SUID, SGID and LSM creds get determined differently
	 * under ptrace.
	 */
	retval = -ERESTARTNOINTR;
	if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
		goto out;

	task_lock(task);
	retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
	task_unlock(task);
	if (retval)
		goto unlock_creds;

	write_lock_irq(&tasklist_lock);
	retval = -EPERM;
	if (unlikely(task->exit_state))
		goto unlock_tasklist;
	if (task->ptrace)
		goto unlock_tasklist;

	task->ptrace = PT_PTRACED;
	if (task_ns_capable(task, CAP_SYS_PTRACE))
		task->ptrace |= PT_PTRACE_CAP;

	__ptrace_link(task, current);
	send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);

	spin_lock(&task->sighand->siglock);

	/*
	 * If the task is already STOPPED, set GROUP_STOP_PENDING and
	 * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
	 * will be cleared if the child completes the transition or any
	 * event which clears the group stop states happens.  We'll wait
	 * for the transition to complete before returning from this
	 * function.
	 *
	 * This hides STOPPED -> RUNNING -> TRACED transition from the
	 * attaching thread but a different thread in the same group can
	 * still observe the transient RUNNING state.  IOW, if another
	 * thread's WNOHANG wait(2) on the stopped tracee races against
	 * ATTACH, the wait(2) may fail due to the transient RUNNING.
	 *
	 * The following task_is_stopped() test is safe as both transitions
	 * in and out of STOPPED are protected by siglock.
	 */
	if (task_is_stopped(task)) {
		task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING;
		signal_wake_up(task, 1);
		wait_trap = true;
	}

	spin_unlock(&task->sighand->siglock);

	retval = 0;
unlock_tasklist:
	write_unlock_irq(&tasklist_lock);
unlock_creds:
	mutex_unlock(&task->signal->cred_guard_mutex);
out:
	if (wait_trap)
		wait_event(current->signal->wait_chldexit,
			   !(task->group_stop & GROUP_STOP_TRAPPING));
	return retval;
}

/**
 * zfcp_unit_enqueue - enqueue unit to unit list of a port.
 * @port: pointer to port where unit is added
 * @fcp_lun: FCP LUN of unit to be enqueued
 * Returns: pointer to enqueued unit on success, ERR_PTR on error
 *
 * Sets up some unit internal structures and creates sysfs entry.
 */
struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, u64 fcp_lun)
{
	struct zfcp_unit *unit;
	int retval = -ENOMEM;

	get_device(&port->dev);

	unit = zfcp_get_unit_by_lun(port, fcp_lun);
	if (unit) {
		put_device(&unit->dev);
		retval = -EEXIST;
		goto err_out;
	}

	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
	if (!unit)
		goto err_out;

	unit->port = port;
	unit->fcp_lun = fcp_lun;
	unit->dev.parent = &port->dev;
	unit->dev.release = zfcp_unit_release;

	if (dev_set_name(&unit->dev, "0x%016llx",
			 (unsigned long long) fcp_lun)) {
		kfree(unit);
		goto err_out;
	}
	retval = -EINVAL;

	INIT_WORK(&unit->scsi_work, zfcp_scsi_scan);

	spin_lock_init(&unit->latencies.lock);
	unit->latencies.write.channel.min = 0xFFFFFFFF;
	unit->latencies.write.fabric.min = 0xFFFFFFFF;
	unit->latencies.read.channel.min = 0xFFFFFFFF;
	unit->latencies.read.fabric.min = 0xFFFFFFFF;
	unit->latencies.cmd.channel.min = 0xFFFFFFFF;
	unit->latencies.cmd.fabric.min = 0xFFFFFFFF;

	if (device_register(&unit->dev)) {
		put_device(&unit->dev);
		goto err_out;
	}

	if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs))
		goto err_out_put;

	write_lock_irq(&port->unit_list_lock);
	list_add_tail(&unit->list, &port->unit_list);
	write_unlock_irq(&port->unit_list_lock);

	atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);

	return unit;

err_out_put:
	device_unregister(&unit->dev);
err_out:
	put_device(&port->dev);
	return ERR_PTR(retval);
}

/**
 * zfcp_port_enqueue - enqueue port to port list of adapter
 * @adapter: adapter where remote port is added
 * @wwpn: WWPN of the remote port to be enqueued
 * @status: initial status for the port
 * @d_id: destination id of the remote port to be enqueued
 * Returns: pointer to enqueued port on success, ERR_PTR on error
 *
 * All port internal structures are set up and the sysfs entry is generated.
 * d_id is used to enqueue ports with a well known address like the Directory
 * Service for nameserver lookup.
 */
struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
				     u32 status, u32 d_id)
{
	struct zfcp_port *port;
	int retval = -ENOMEM;

	kref_get(&adapter->ref);

	port = zfcp_get_port_by_wwpn(adapter, wwpn);
	if (port) {
		put_device(&port->dev);
		retval = -EEXIST;
		goto err_out;
	}

	port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
	if (!port)
		goto err_out;

	rwlock_init(&port->unit_list_lock);
	INIT_LIST_HEAD(&port->unit_list);

	INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
	INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
	INIT_WORK(&port->rport_work, zfcp_scsi_rport_work);

	port->adapter = adapter;
	port->d_id = d_id;
	port->wwpn = wwpn;
	port->rport_task = RPORT_NONE;
	port->dev.parent = &adapter->ccw_device->dev;
	port->dev.release = zfcp_port_release;

	if (dev_set_name(&port->dev, "0x%016llx", (unsigned long long)wwpn)) {
		kfree(port);
		goto err_out;
	}
	retval = -EINVAL;

	if (device_register(&port->dev)) {
		put_device(&port->dev);
		goto err_out;
	}

	if (sysfs_create_group(&port->dev.kobj,
			       &zfcp_sysfs_port_attrs))
		goto err_out_put;

	write_lock_irq(&adapter->port_list_lock);
	list_add_tail(&port->list, &adapter->port_list);
	write_unlock_irq(&adapter->port_list_lock);

	atomic_set_mask(status | ZFCP_STATUS_COMMON_RUNNING, &port->status);

	return port;

err_out_put:
	device_unregister(&port->dev);
err_out:
	zfcp_ccw_adapter_put(adapter);
	return ERR_PTR(retval);
}

//.........这里部分代码省略.........
	 * The task hasn't been attached yet, so its cpus_allowed mask will
	 * not be changed, nor will its assigned CPU.
	 *
	 * The cpus_allowed mask of the parent may have changed after it was
	 * copied first time - so re-copy it here, then check the child's CPU
	 * to ensure it is on a valid CPU (and if not, just force it back to
	 * parent's CPU). This avoids alot of nasty races.
	 */
	p->cpus_allowed = current->cpus_allowed;
	if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
			!cpu_online(task_cpu(p))))
		set_task_cpu(p, smp_processor_id());

	/* CLONE_PARENT re-uses the old parent */
	if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
		p->real_parent = current->real_parent;
	else
		p->real_parent = current;
	p->parent = p->real_parent;

	spin_lock(&current->sighand->siglock);

	/*
	 * Process group and session signals need to be delivered to just the
	 * parent before the fork or both the parent and the child after the
	 * fork. Restart if a signal comes in before we add the new process to
	 * it's process group.
	 * A fatal signal pending means that current will exit, so the new
	 * thread can't slip out of an OOM kill (or normal SIGKILL).
 	 */
 	recalc_sigpending();
	if (signal_pending(current)) {
		spin_unlock(&current->sighand->siglock);
		write_unlock_irq(&tasklist_lock);
		retval = -ERESTARTNOINTR;
		goto bad_fork_cleanup_namespaces;
	}

	if (clone_flags & CLONE_THREAD) {
		p->group_leader = current->group_leader;
		list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);

		if (!cputime_eq(current->signal->it_virt_expires,
				cputime_zero) ||
		    !cputime_eq(current->signal->it_prof_expires,
				cputime_zero) ||
		    current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY ||
		    !list_empty(&current->signal->cpu_timers[0]) ||
		    !list_empty(&current->signal->cpu_timers[1]) ||
		    !list_empty(&current->signal->cpu_timers[2])) {
			/*
			 * Have child wake up on its first tick to check
			 * for process CPU timers.
			 */
			p->it_prof_expires = jiffies_to_cputime(1);
		}
	}

	if (likely(p->pid)) {
		add_parent(p);
		if (unlikely(p->ptrace & PT_PTRACED))
			__ptrace_link(p, current->parent);

		if (thread_group_leader(p)) {
			p->signal->tty = current->signal->tty;
			p->signal->pgrp = process_group(current);

/**
 * write_one_page - write out a single page and optionally wait on I/O
 * @page: the page to write
 * @wait: if true, wait on writeout
 *
 * The page must be locked by the caller and will be unlocked upon return.
 *
 * write_one_page() returns a negative error code if I/O failed.
 */
int write_one_page(struct page *page, int wait)
{
	struct address_space *mapping = page->mapping;
	int ret = 0;
	struct writeback_control wbc = {
		.sync_mode = WB_SYNC_ALL,
		.nr_to_write = 1,
	};

	BUG_ON(!PageLocked(page));

	if (wait)
		wait_on_page_writeback(page);

	if (clear_page_dirty_for_io(page)) {
		page_cache_get(page);
		ret = mapping->a_ops->writepage(page, &wbc);
		if (ret == 0 && wait) {
			wait_on_page_writeback(page);
			if (PageError(page))
				ret = -EIO;
		}
		page_cache_release(page);
	} else {
		unlock_page(page);
	}
	return ret;
}
EXPORT_SYMBOL(write_one_page);

/*
 * For address_spaces which do not use buffers nor write back.
 */
int __set_page_dirty_no_writeback(struct page *page)
{
	if (!PageDirty(page))
		SetPageDirty(page);
	return 0;
}

/*
 * For address_spaces which do not use buffers.  Just tag the page as dirty in
 * its radix tree.
 *
 * This is also used when a single buffer is being dirtied: we want to set the
 * page dirty in that case, but not all the buffers.  This is a "bottom-up"
 * dirtying, whereas __set_page_dirty_buffers() is a "top-down" dirtying.
 *
 * Most callers have locked the page, which pins the address_space in memory.
 * But zap_pte_range() does not lock the page, however in that case the
 * mapping is pinned by the vma's ->vm_file reference.
 *
 * We take care to handle the case where the page was truncated from the
 * mapping by re-checking page_mapping() insode tree_lock.
 */
int __set_page_dirty_nobuffers(struct page *page)
{
	if (!TestSetPageDirty(page)) {
		struct address_space *mapping = page_mapping(page);
		struct address_space *mapping2;

		if (!mapping)
			return 1;

		write_lock_irq(&mapping->tree_lock);
		mapping2 = page_mapping(page);
		if (mapping2) { /* Race with truncate? */
			BUG_ON(mapping2 != mapping);
			WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
			if (mapping_cap_account_dirty(mapping)) {
				__inc_zone_page_state(page, NR_FILE_DIRTY);
				task_io_account_write(PAGE_CACHE_SIZE);
			}
			radix_tree_tag_set(&mapping->page_tree,
				page_index(page), PAGECACHE_TAG_DIRTY);
		}
		write_unlock_irq(&mapping->tree_lock);
		if (mapping->host) {
			/* !PageAnon && !swapper_space */
			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
		}
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL(__set_page_dirty_nobuffers);

/*
 * When a writepage implementation decides that it doesn't want to write this
 * page for some reason, it should redirty the locked page via
 * redirty_page_for_writepage() and it should then unlock the page and return 0
//.........这里部分代码省略.........