#include <linux/fault-inject.h>
#include <linux/gfp.h>
#include <linux/slab.h>

static struct {
	struct fault_attr attr;
	u32 ignore_gfp_wait;
	int cache_filter;
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
	struct dentry *ignore_gfp_wait_file;
	struct dentry *cache_filter_file;
#endif
} failslab = {
	.attr = FAULT_ATTR_INITIALIZER,
	.ignore_gfp_wait = 1,
	.cache_filter = 0,
};

bool should_failslab(size_t size, gfp_t gfpflags, unsigned long cache_flags)
{
	if (gfpflags & __GFP_NOFAIL)
		return false;

        if (failslab.ignore_gfp_wait && (gfpflags & __GFP_WAIT))
		return false;

	if (failslab.cache_filter && !(cache_flags & SLAB_FAILSLAB))
		return false;

	return should_fail(&failslab.attr, size);
}

static int __init setup_failslab(char *str)
{
	return setup_fault_attr(&failslab.attr, str);
}
__setup("failslab=", setup_failslab);

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int __init failslab_debugfs_init(void)
{
	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;
	int err;

	err = init_fault_attr_dentries(&failslab.attr, "failslab");
	if (err)
		return err;
	dir = failslab.attr.dentries.dir;

	failslab.ignore_gfp_wait_file =
		debugfs_create_bool("ignore-gfp-wait", mode, dir,
				      &failslab.ignore_gfp_wait);

	failslab.cache_filter_file =
		debugfs_create_bool("cache-filter", mode, dir,
				      &failslab.cache_filter);

	if (!failslab.ignore_gfp_wait_file ||
	    !failslab.cache_filter_file) {
		err = -ENOMEM;
		debugfs_remove(failslab.cache_filter_file);
		debugfs_remove(failslab.ignore_gfp_wait_file);
		cleanup_fault_attr_dentries(&failslab.attr);
	}

	return err;
}

late_initcall(failslab_debugfs_init);

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */