On Thu, 2018-02-22 at 04:19 +0000, Damien Le Moal wrote:
> It looks OK to me, at least if CONFIG_DEBUG_OBJECTS_RCU_HEAD is turned
> off since the init_rcu_head() and destroy_rcu_head() functions only care
> about that.
>
> With rcu head debug turned on, I am not so sure. The object debug code
> will have references to unused rcu heads left behind for unused scsi
> cmds, which are indeed dynamically allocated for a device together with
> requests when the device is initialized, but they are never freed until
> the device is removed. So "dynamically allocated object", yes, but that
> does not match the use of the object done in scsi (i.e. alloc before use
> + free after use).
Hello Damien,
Please have a look at the following part of
Documentation/RCU/Design/Requirements/Requirements.html:
Similarly, statically allocated non-stack <tt>rcu_head</tt>
structures must be initialized with <tt>init_rcu_head()</tt>
and cleaned up with <tt>destroy_rcu_head()</tt>.
Thanks,
Bart.
