C++ (Cpp) alloc_io_context Examples

Example #1

int set_task_ioprio(struct task_struct *task, int ioprio)
{
#ifdef CONFIG_IOSCHED_BFQ
	int err, i;
#else
	int err;
#endif
	struct io_context *ioc;
	const struct cred *cred = current_cred(), *tcred;

	rcu_read_lock();
	tcred = __task_cred(task);
	if (tcred->uid != cred->euid &&
	    tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) {
		rcu_read_unlock();
		return -EPERM;
	}
	rcu_read_unlock();

	err = security_task_setioprio(task, ioprio);
	if (err)
		return err;

	task_lock(task);
	do {
		ioc = task->io_context;
		/* see wmb() in current_io_context() */
		smp_read_barrier_depends();
		if (ioc)
			break;

		ioc = alloc_io_context(GFP_ATOMIC, -1);
		if (!ioc) {
			err = -ENOMEM;
			break;
		}
#ifdef CONFIG_IOSCHED_BFQ
		/* let other ioc users see the new values */
		smp_wmb();
#endif
		task->io_context = ioc;
	} while (1);

	if (!err) {
		ioc->ioprio = ioprio;
#ifdef CONFIG_IOSCHED_BFQ
		/* make sure schedulers see the new ioprio value */
		wmb();
		for (i = 0; i < IOC_IOPRIO_CHANGED_BITS; i++)
			set_bit(i, ioc->ioprio_changed);
#else
		ioc->ioprio_changed = 1;
#endif
	}

	task_unlock(task);
	return err;
}

Example #2

File: ioprio.c Project: hounjini/htc-rider-cm-kernel

int set_task_ioprio(struct task_struct *task, int ioprio)
{
	int err, i;
	struct io_context *ioc;
	const struct cred *cred = current_cred(), *tcred;

	rcu_read_lock();
	tcred = __task_cred(task);
	if (tcred->uid != cred->euid &&
	    tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) {
		rcu_read_unlock();
		return -EPERM;
	}
	rcu_read_unlock();

	err = security_task_setioprio(task, ioprio);
	if (err)
		return err;

	task_lock(task);
	do {
		ioc = task->io_context;
		/* see wmb() in current_io_context() */
		smp_read_barrier_depends();
		if (ioc)
			break;

		ioc = alloc_io_context(GFP_ATOMIC, -1);
		if (!ioc) {
			err = -ENOMEM;
			break;
		}
		smp_wmb();
		task->io_context = ioc;
	} while (1);

	if (!err) {
		ioc->ioprio = ioprio;
		wmb();
		for (i = 0; i < IOC_IOPRIO_CHANGED_BITS; i++)
			set_bit(i, ioc->ioprio_changed);
	}

	task_unlock(task);
	return err;
}

Example #3

File: blk-ioc.c Project: mbin/LiteKernel---Glide

/*
 * If the current task has no IO context then create one and initialise it.
 * Otherwise, return its existing IO context.
 *
 * This returned IO context doesn't have a specifically elevated refcount,
 * but since the current task itself holds a reference, the context can be
 * used in general code, so long as it stays within `current` context.
 */
struct io_context *current_io_context(gfp_t gfp_flags, int node)
{
	struct task_struct *tsk = current;
	struct io_context *ret;

	ret = tsk->io_context;
	if (likely(ret))
		return ret;

	ret = alloc_io_context(gfp_flags, node);
	if (ret) {
		/* make sure set_task_ioprio() sees the settings above */
		smp_wmb();
		tsk->io_context = ret;
	}

	return ret;
}

Example #4

File: fork.c Project: genua/anoubis_os

static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
{
#ifdef CONFIG_BLOCK
	struct io_context *ioc = current->io_context;

	if (!ioc)
		return 0;
	/*
	 * Share io context with parent, if CLONE_IO is set
	 */
	if (clone_flags & CLONE_IO) {
		tsk->io_context = ioc_task_link(ioc);
		if (unlikely(!tsk->io_context))
			return -ENOMEM;
	} else if (ioprio_valid(ioc->ioprio)) {
		tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
		if (unlikely(!tsk->io_context))
			return -ENOMEM;

		tsk->io_context->ioprio = ioc->ioprio;
	}
#endif
	return 0;
}