From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424873AbcFMPtz (ORCPT ); Mon, 13 Jun 2016 11:49:55 -0400 Received: from imap.thunk.org ([74.207.234.97]:45070 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424680AbcFMPt3 (ORCPT ); Mon, 13 Jun 2016 11:49:29 -0400 From: "Theodore Ts'o" To: Linux Kernel Developers List Cc: linux-crypto@vger.kernel.org, smueller@chronox.de, herbert@gondor.apana.org.au, andi@firstfloor.org, sandyinchina@gmail.com, jsd@av8n.com, hpa@zytor.com, "Theodore Ts'o" , stable@kernel.org Subject: [PATCH 1/7] random: initialize the non-blocking pool via add_hwgenerator_randomness() Date: Mon, 13 Jun 2016 11:48:33 -0400 Message-Id: <1465832919-11316-2-git-send-email-tytso@mit.edu> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1465832919-11316-1-git-send-email-tytso@mit.edu> References: <1465832919-11316-1-git-send-email-tytso@mit.edu> X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we have a hardware RNG and are using the in-kernel rngd, we should use this to initialize the non-blocking pool so that getrandom(2) doesn't block unnecessarily. Cc: stable@kernel.org Signed-off-by: Theodore Ts'o --- drivers/char/random.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 0158d3b..4e2627a 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1849,12 +1849,18 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, { struct entropy_store *poolp = &input_pool; - /* Suspend writing if we're above the trickle threshold. - * We'll be woken up again once below random_write_wakeup_thresh, - * or when the calling thread is about to terminate. - */ - wait_event_interruptible(random_write_wait, kthread_should_stop() || + if (unlikely(nonblocking_pool.initialized == 0)) + poolp = &nonblocking_pool; + else { + /* Suspend writing if we're above the trickle + * threshold. We'll be woken up again once below + * random_write_wakeup_thresh, or when the calling + * thread is about to terminate. + */ + wait_event_interruptible(random_write_wait, + kthread_should_stop() || ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits); + } mix_pool_bytes(poolp, buffer, count); credit_entropy_bits(poolp, entropy); } -- 2.5.0