linux-kernel - [PATCH RFC] random: Reduce preempt disabled region

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Message-Id: <20180504113947.26254-1-bigeasy@linutronix.de>
Date:   Fri,  4 May 2018 13:39:47 +0200
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, Ingo Molnar <mingo@...e.hu>,
        "Theodore Ts'o" <tytso@....edu>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH RFC] random: Reduce preempt disabled region

From: Ingo Molnar <mingo@...e.hu>

No need to keep preemption disabled across the whole function.

Cc: "Theodore Ts'o" <tytso@....edu>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 drivers/char/random.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1122,8 +1122,6 @@ static void add_timer_randomness(struct
 	} sample;
 	long delta, delta2, delta3;
 
-	preempt_disable();
-
 	sample.jiffies = jiffies;
 	sample.cycles = random_get_entropy();
 	sample.num = num;
@@ -1161,8 +1159,6 @@ static void add_timer_randomness(struct
 	 * and limit entropy entimate to 12 bits.
 	 */
 	credit_entropy_bits(r, min_t(int, fls(delta>>1), 11));
-
-	preempt_enable();
 }
 
 void add_input_randomness(unsigned int type, unsigned int code,