Re: [patch 02/17] Kernel Tracepoints

[Steven Rostedt]

On Tue, 15 Jul 2008, Mathieu Desnoyers wrote:
> +static void *
> +tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
> +{
> +	int nr_probes = 0, nr_del = 0, i;
> +	void **old, **new;
> +
> +	old = entry->funcs;
> +
> +	debug_print_probes(entry);
> +	/* (N -> M), (N > 1, M >= 0) probes */
> +	for (nr_probes = 0; old[nr_probes]; nr_probes++) {
> +		if ((!probe || old[nr_probes] == probe))
> +			nr_del++;
> +	}
> +
> +	if (nr_probes - nr_del == 0) {
> +		/* N -> 0, (N > 1) */
> +		entry->funcs = NULL;
> +		entry->refcount = 0;
> +		debug_print_probes(entry);
> +		return old;
> +	} else {
> +		int j = 0;
> +		/* N -> M, (N > 1, M > 0) */
> +		/* + 1 for NULL */
> +		new = kzalloc((nr_probes - nr_del + 1)
> +			* sizeof(void *), GFP_KERNEL);
> +		if (new == NULL)
> +			return ERR_PTR(-ENOMEM);

Hmm, on failure of allocating a new array, we could simply use the
old array, and remove the one probe from it instead of just failing.

-- Steve

> +		for (i = 0; old[i]; i++)
> +			if ((probe && old[i] != probe))
> +				new[j++] = old[i];
> +		entry->refcount = nr_probes - nr_del;
> +		entry->funcs = new;
> +	}
> +	debug_print_probes(entry);
> +	return old;
> +}
> +
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/