On 02/02/2017 02:19 AM, Paolo Valente wrote:

The scheme is clear.  One comment, in case it could make sense and
avoid more complexity: since put_rq_priv is invoked in two different
contexts, process or interrupt, I didn't feel so confusing that, when
put_rq_priv is invoked in the context where the lock cannot be held
(unless one is willing to pay with irq disabling all the times), the
lock is not held, while, when invoked in the context where the lock
can be held, the lock is actually held, or must be taken.

If you grab the same lock from put_rq_priv, yes, you must make it IRQ
disabling in all contexts, and use _irqsave() from put_rq_priv. If it's
just freeing resources, you could potentially wait and do that when
someone else needs them, since that part will come from proces context.
That would need two locks, though.

As I said above, I would not worry about the IRQ disabling lock.

-- 
Jens Axboe