| From 20690515ca3fd9baa92a3c915c74b14290fef13c Mon Sep 17 00:00:00 2001 |
| From: Ingo Molnar <mingo@elte.hu> |
| Date: Fri, 3 Jul 2009 08:29:30 -0500 |
| Subject: [PATCH] random: Remove preempt disabled region |
| |
| No need to keep preemption disabled across the whole function. |
| |
| mix_pool_bytes() uses a spin_lock() to protect the pool and there are |
| other places like write_pool() whhich invoke mix_pool_bytes() without |
| disabling preemption. |
| credit_entropy_bits() is invoked from other places like |
| add_hwgenerator_randomness() without disabling preemption. |
| |
| Before commit 95b709b6be49 ("random: drop trickle mode") the function |
| used __this_cpu_inc_return() which would require disabled preemption. |
| The preempt_disable() section was added in commit 43d5d3018c37 ("[PATCH] |
| random driver preempt robustness", history tree). It was claimed that |
| the code relied on "vt_ioctl() being called under BKL". |
| |
| Cc: "Theodore Ts'o" <tytso@mit.edu> |
| Signed-off-by: Ingo Molnar <mingo@elte.hu> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| [bigeasy: enhance the commit message] |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| drivers/char/random.c | 3 --- |
| 1 file changed, 3 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; |
| @@ -1164,7 +1162,6 @@ static void add_timer_randomness(struct |
| */ |
| credit_entropy_bits(r, min_t(int, fls(delta>>1), 11)); |
| } |
| - preempt_enable(); |
| } |
| |
| void add_input_randomness(unsigned int type, unsigned int code, |
