1 files changed, 112 insertions, 0 deletions

diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c
new file mode 100644
index 000000000000..44b92cb6224f
--- /dev/null
+++ b/lib/notifier-error-inject.c
@@ -0,0 +1,112 @@
+#include <linux/module.h>
+
+#include "notifier-error-inject.h"
+
+static int debugfs_errno_set(void *data, u64 val)
+{
+        *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
+        return 0;
+}
+
+static int debugfs_errno_get(void *data, u64 *val)
+{
+        *val = *(int *)data;
+        return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
+                        "%lld\n");
+
+static struct dentry *debugfs_create_errno(const char *name, mode_t mode,
+                                struct dentry *parent, int *value)
+{
+        return debugfs_create_file(name, mode, parent, value, &fops_errno);
+}
+
+static int notifier_err_inject_callback(struct notifier_block *nb,
+                                unsigned long val, void *p)
+{
+        int err = 0;
+        struct notifier_err_inject *err_inject =
+                container_of(nb, struct notifier_err_inject, nb);
+        struct notifier_err_inject_action *action;
+
+        for (action = err_inject->actions; action->name; action++) {
+                if (action->val == val) {
+                        err = action->error;
+                        break;
+                }
+        }
+        if (err)
+                pr_info("Injecting error (%d) to %s\n", err, action->name);
+
+        return notifier_from_errno(err);
+}
+
+struct dentry *notifier_err_inject_dir;
+EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
+
+struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
+                        struct notifier_err_inject *err_inject, int priority)
+{
+        struct notifier_err_inject_action *action;
+        mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
+        struct dentry *dir;
+        struct dentry *actions_dir;
+
+        err_inject->nb.notifier_call = notifier_err_inject_callback;
+        err_inject->nb.priority = priority;
+
+        dir = debugfs_create_dir(name, parent);
+        if (!dir)
+                return ERR_PTR(-ENOMEM);
+
+        actions_dir = debugfs_create_dir("actions", dir);
+        if (!actions_dir)
+                goto fail;
+
+        for (action = err_inject->actions; action->name; action++) {
+                struct dentry *action_dir;
+
+                action_dir = debugfs_create_dir(action->name, actions_dir);
+                if (!action_dir)
+                        goto fail;
+
+                /*
+                 * Create debugfs r/w file containing action->error. If
+                 * notifier call chain is called with action->val, it will
+                 * fail with the error code
+                 */
+                if (!debugfs_create_errno("error", mode, action_dir,
+                                        &action->error))
+                        goto fail;
+        }
+        return dir;
+fail:
+        debugfs_remove_recursive(dir);
+        return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(notifier_err_inject_init);
+
+static int __init err_inject_init(void)
+{
+        notifier_err_inject_dir =
+                debugfs_create_dir("notifier-error-inject", NULL);
+
+        if (!notifier_err_inject_dir)
+                return -ENOMEM;
+
+        return 0;
+}
+
+static void __exit err_inject_exit(void)
+{
+        debugfs_remove_recursive(notifier_err_inject_dir);
+}
+
+module_init(err_inject_init);
+module_exit(err_inject_exit);
+
+MODULE_DESCRIPTION("Notifier error injection module");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");