1 files changed, 73 insertions, 0 deletions
diff --git a/mm/failslab.c b/mm/failslab.c
new file mode 100644
index 000000000..ffc420c0e
--- /dev/null
+++ b/mm/failslab.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fault-inject.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include "slab.h"
+
+static struct {
+	struct fault_attr attr;
+	bool ignore_gfp_reclaim;
+	bool cache_filter;
+} failslab = {
+	.attr = FAULT_ATTR_INITIALIZER,
+	.ignore_gfp_reclaim = true,
+	.cache_filter = false,
+};
+
+bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
+{
+	int flags = 0;
+
+	/* No fault-injection for bootstrap cache */
+	if (unlikely(s == kmem_cache))
+		return false;
+
+	if (gfpflags & __GFP_NOFAIL)
+		return false;
+
+	if (failslab.ignore_gfp_reclaim &&
+			(gfpflags & __GFP_DIRECT_RECLAIM))
+		return false;
+
+	if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
+		return false;
+
+	/*
+	 * In some cases, it expects to specify __GFP_NOWARN
+	 * to avoid printing any information(not just a warning),
+	 * thus avoiding deadlocks. See commit 6b9dbedbe349 for
+	 * details.
+	 */
+	if (gfpflags & __GFP_NOWARN)
+		flags |= FAULT_NOWARN;
+
+	return should_fail_ex(&failslab.attr, s->object_size, flags);
+}
+
+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)
+{
+	struct dentry *dir;
+	umode_t mode = S_IFREG | 0600;
+
+	dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	debugfs_create_bool("ignore-gfp-wait", mode, dir,
+			    &failslab.ignore_gfp_reclaim);
+	debugfs_create_bool("cache-filter", mode, dir,
+			    &failslab.cache_filter);
+
+	return 0;
+}
+
+late_initcall(failslab_debugfs_init);
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */