static void record_obj(unsigned long handle, unsigned long obj)
{
- *(unsigned long *)handle = obj;
+ /*
+ * lsb of @obj represents handle lock while other bits
+ * represent object value the handle is pointing so
+ * updating shouldn't do store tearing.
+ */
+ WRITE_ONCE(*(unsigned long *)handle, obj);
}
/* zpool driver */
free_obj = obj_malloc(d_page, class, handle);
zs_object_copy(free_obj, used_obj, class);
index++;
+ /*
+ * record_obj updates handle's value to free_obj and it will
+ * invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which
+ * breaks synchronization using pin_tag(e,g, zs_free) so
+ * let's keep the lock bit.
+ */
+ free_obj |= BIT(HANDLE_PIN_BIT);
record_obj(handle, free_obj);
unpin_tag(handle);
obj_free(pool, class, used_obj);