linux-kernel - Re: [PATCH v3] keys: update key quotas in key

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Message-ID: <3007646.1707134664@warthog.procyon.org.uk>
Date: Mon, 05 Feb 2024 12:04:24 +0000
From: David Howells <dhowells@...hat.com>
To: Luis Henriques <lhenriques@...e.de>
Cc: dhowells@...hat.com, Jarkko Sakkinen <jarkko@...nel.org>,
    Eric Biggers <ebiggers@...nel.org>, keyrings@...r.kernel.org,
    linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] keys: update key quotas in key_put()

Luis Henriques <lhenriques@...e.de> wrote:

> Delaying key quotas update when key's refcount reaches 0 in key_put() has
> been causing some issues in fscrypt testing, specifically in fstest
> generic/581.  This commit fixes this test flakiness by dealing with the
> quotas immediately, and leaving all the other clean-ups to the key garbage
> collector.

Okay, I'll accept this.

> This is done by moving the updates to the qnkeys and qnbytes fields in
> struct key_user from key_gc_unused_keys() into key_put().  Unfortunately,
> this also means that we need to switch to the irq-version of the spinlock
> that protects these fields and use spin_lock_{irqsave,irqrestore} in all the
> code that touches these fields.

.. Which shouldn't be that often.  It only happens when a key is created or
finally let go of.

> Signed-off-by: Luis Henriques <lhenriques@...e.de>

Acked-by: David Howells <dhowells@...hat.com>

Jarkko - could you pick this up?