From patchwork Wed Apr 30 15:25:53 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 886174 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 50C1117C21B; Wed, 30 Apr 2025 15:26:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746026765; cv=none; b=KHSROh7obxkWLX6Rfd72r+4DIBmR8W03HAq6LHDVVNXIExXob1HhoUXla10X3LWqokzPXKTGqxCMXQGBsgjwwpm/hlnV+3blev1DKoBAhr8xF/lwEXf/JXP6C09hwR1SidkaNx6WhYGg7N26rl/ftvlHLXfZfFgnuVZi1rBHxSg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746026765; c=relaxed/simple; bh=9BnNSNbGk/SH1Jqts3LNDoiGPJQv2lBeVhQ2pLakZsw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Zq7t3SHQCkqiUq5Ka3oZqe7teB2/l88QA5eUu7QkrJzQbOlNEXsHtGNGOzzXB5YsalDNjD09yTz6mPIP67jNeIJkt0o7ts/fYBCpJ607iYAWoL909e/r6aLbzl7sLCMpICsaCaXPejJ7ctIZENUbUUnkP7maHjjOID0zgjFHd/s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iM4NQQ9a; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iM4NQQ9a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49966C4CEE7; Wed, 30 Apr 2025 15:26:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746026764; bh=9BnNSNbGk/SH1Jqts3LNDoiGPJQv2lBeVhQ2pLakZsw=; h=From:To:Cc:Subject:Date:From; b=iM4NQQ9aK4CcuaIjYAyxqodWnUl+aox9OAEYJdvXBTMwtwGmpzFk19Y6IzVhayOF5 RP0a7qLN+VGxIQKn1td/abgVsoTSc+6eJ/sQpcdXyJ+KCj9PgPzj3c7DtakarSxnvV 6uNZU4P666ukUB553+c4yN7mBIEsuCYB9HaF+Zp5/BmoHe4pXtBlHzfaXSolkQVpOz XG4KUcCIl5szp+HHlw5nc1um/+KJI8qHsw8bqKy2jQE4pO/dN1X8hOBU1pZNS0oU6Z V4N2f1MzKqHSM9Peo7UiqF298c2ZmKdx/69w61O50Pp6QrRdGvNO/XgFieetKB8vGF NszNzEM/uon1w== From: Jarkko Sakkinen To: keyrings@vger.kernel.org Cc: Jarkko Sakkinen , David Howells , Lukas Wunner , Ignat Korchagin , Herbert Xu , "David S. Miller" , Peter Huewe , Jason Gunthorpe , Paul Moore , James Morris , "Serge E. Hallyn" , James Bottomley , Mimi Zohar , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH] KEYS: Reduce smp_mb() calls in key_put() Date: Wed, 30 Apr 2025 18:25:53 +0300 Message-ID: <20250430152554.23646-1-jarkko@kernel.org> X-Mailer: git-send-email 2.47.2 Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Rely only on the memory ordering of spin_unlock() when setting KEY_FLAG_FINAL_PUT under key->user->lock in key_put(). Signed-off-by: Jarkko Sakkinen --- security/keys/key.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/security/keys/key.c b/security/keys/key.c index 7198cd2ac3a3..aecbd624612d 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -656,10 +656,12 @@ void key_put(struct key *key) spin_lock_irqsave(&key->user->lock, flags); key->user->qnkeys--; key->user->qnbytes -= key->quotalen; + set_bit(KEY_FLAG_FINAL_PUT, &key->flags); spin_unlock_irqrestore(&key->user->lock, flags); + } else { + set_bit(KEY_FLAG_FINAL_PUT, &key->flags); + smp_mb(); /* key->user before FINAL_PUT set. */ } - smp_mb(); /* key->user before FINAL_PUT set. */ - set_bit(KEY_FLAG_FINAL_PUT, &key->flags); schedule_work(&key_gc_work); } }