From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1519860181; cv=none; d=google.com; s=arc-20160816; b=b7UOrkfngbGb7VzJIUPNLm9u2oCb4QQYTlN2UKVxPaZ61W0O2FABdmBXlHkE0+uGb6 YDW5sTWX+FLa4I/V9sa9Q1En7+xJtsg2J7ntt24v4P2THBWpXjDKxh2JjG75qm7ayynk ImBLwHEUmu1tybnF8v3hhSrJeCZMHEMhuCHvas8YqLtSO+LJ1dkwIdIxx0g6B+Rlh4hS Wc1tiSaFstLua3Z83Sot/irbPnkdJjAWU9vERV30FTEuuMC4BgJ6KFxwM5CGErXvfiaD jVKHDb1f2C6kVr95SzZ/dPN8lTHamPca8MOCUoXBjilTezQfv6roSFFoamiJWCMqCgEh 889w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:subject:cc:to:from:dkim-signature :arc-authentication-results; bh=y4lIwZBy83kkAtY3JWGGMiDSThgTEzVLEUw27b5wT4I=; b=fxrLT15MJTgpevpBBpB914iAnnWioE0AD2n2dFzllKZWWaqvNqB6FeSJd/wPaocL0T Ui9jYx6/1QPNmsOiYT3l+a6RGimquhwPO5SY7Bq5tIINRJbVMDYorzxh/mSWlNbBxVfs HlnxPy/alvynbsShS2bRSxSWABHba3mAvi+qg+M9CizL3EbGPFOERQ4sb7vPSy4mQKHu E3YLUoFtODKqM+pKJTVPzS1RV7d58FLcendF4A17oRPY1ZviVa7Gc9KuOYN1KkVHaLHP 3JVw32uzHMlL6cksNnMOqcBurz0UFR2zBp8wip4esCn018FIHM1J/aDXTe2kXl6FbHDd ehZg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@rasmusvillemoes.dk header.s=google header.b=T0ZAYtt5; spf=pass (google.com: domain of linux@rasmusvillemoes.dk designates 209.85.220.65 as permitted sender) smtp.mailfrom=linux@rasmusvillemoes.dk Authentication-Results: mx.google.com; dkim=pass header.i=@rasmusvillemoes.dk header.s=google header.b=T0ZAYtt5; spf=pass (google.com: domain of linux@rasmusvillemoes.dk designates 209.85.220.65 as permitted sender) smtp.mailfrom=linux@rasmusvillemoes.dk X-Google-Smtp-Source: AG47ELufW4cBhinitqkFKK+tTrXKvqgAREsZJvzkQ2ts16CewFMmVsVa8i5MA+By6defXlTkiJlr0w== From: Rasmus Villemoes To: "Theodore Ts'o" , Arnd Bergmann , Greg Kroah-Hartman Cc: Rasmus Villemoes , linux-kernel@vger.kernel.org Subject: [PATCH resend] drivers/char/random.c: remove unused dont_count_entropy Date: Thu, 1 Mar 2018 00:22:47 +0100 Message-Id: <20180228232247.16368-1-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.15.1 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1593688909749149990?= X-GMAIL-MSGID: =?utf-8?q?1593688909749149990?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Ever since "random: kill dead extract_state struct" [1], the dont_count_entropy member of struct timer_rand_state has been effectively unused. Since it hasn't found a new use in 12 years, it's probably safe to finally kill it. [1] Pre-git, https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=c1c48e61c251f57e7a3f1bf11b3c462b2de9dcb5 Signed-off-by: Rasmus Villemoes --- drivers/char/random.c | 53 ++++++++++++++++++++++++--------------------------- 1 file changed, 25 insertions(+), 28 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index e5b3d3ba4660..767c6c10f9a3 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -963,7 +963,6 @@ static ssize_t extract_crng_user(void __user *buf, size_t nbytes) struct timer_rand_state { cycles_t last_time; long last_delta, last_delta2; - unsigned dont_count_entropy:1; }; #define INIT_TIMER_RAND_STATE { INITIAL_JIFFIES, }; @@ -1029,35 +1028,33 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) * We take into account the first, second and third-order deltas * in order to make our estimate. */ + delta = sample.jiffies - state->last_time; + state->last_time = sample.jiffies; + + delta2 = delta - state->last_delta; + state->last_delta = delta; + + delta3 = delta2 - state->last_delta2; + state->last_delta2 = delta2; + + if (delta < 0) + delta = -delta; + if (delta2 < 0) + delta2 = -delta2; + if (delta3 < 0) + delta3 = -delta3; + if (delta > delta2) + delta = delta2; + if (delta > delta3) + delta = delta3; - if (!state->dont_count_entropy) { - delta = sample.jiffies - state->last_time; - state->last_time = sample.jiffies; - - delta2 = delta - state->last_delta; - state->last_delta = delta; - - delta3 = delta2 - state->last_delta2; - state->last_delta2 = delta2; - - if (delta < 0) - delta = -delta; - if (delta2 < 0) - delta2 = -delta2; - if (delta3 < 0) - delta3 = -delta3; - if (delta > delta2) - delta = delta2; - if (delta > delta3) - delta = delta3; + /* + * delta is now minimum absolute delta. + * Round down by 1 bit on general principles, + * and limit entropy entimate to 12 bits. + */ + credit_entropy_bits(r, min_t(int, fls(delta>>1), 11)); - /* - * delta is now minimum absolute delta. - * Round down by 1 bit on general principles, - * and limit entropy entimate to 12 bits. - */ - credit_entropy_bits(r, min_t(int, fls(delta>>1), 11)); - } preempt_enable(); } -- 2.15.1