linux-kernel - [PATCH RT 1/9] Revert "random: Use local locks for crng context access"

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Message-Id: <20221024104425.16423-2-wagi@monom.org>
Date:   Mon, 24 Oct 2022 12:44:17 +0200
From:   Daniel Wagner <wagi@...om.org>
To:     LKML <linux-kernel@...r.kernel.org>,
        linux-rt-users <linux-rt-users@...r.kernel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Carsten Emde <C.Emde@...dl.org>,
        John Kacur <jkacur@...hat.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Clark Williams <williams@...hat.com>,
        Pavel Machek <pavel@...x.de>
Cc:     Daniel Wagner <wagi@...om.org>
Subject: [PATCH RT 1/9] Revert "random: Use local locks for crng context access"

v4.19.255-rt114-rc1 stable review patch.
If anyone has any objections, please let me know.

-----------


This reverts commit af5469c6f4f85f60f3ecc9bd541adfb6bdbeaff2.
---
 drivers/char/random.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index c06705a32246..2be38780a7f7 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -53,7 +53,6 @@
 #include <linux/uaccess.h>
 #include <linux/siphash.h>
 #include <linux/uio.h>
-#include <linux/locallock.h>
 #include <crypto/chacha20.h>
 #include <crypto/blake2s.h>
 #include <asm/processor.h>
@@ -235,7 +234,6 @@ struct crng {
 static DEFINE_PER_CPU(struct crng, crngs) = {
 	.generation = ULONG_MAX
 };
-DEFINE_LOCAL_IRQ_LOCK(crngs_lock);
 
 /* Used by crng_reseed() and crng_make_state() to extract a new seed from the input pool. */
 static void extract_entropy(void *buf, size_t len);
@@ -364,7 +362,7 @@ static void crng_make_state(u32 chacha_state[CHACHA20_BLOCK_SIZE / sizeof(u32)],
 	if (unlikely(crng_has_old_seed()))
 		crng_reseed();
 
-	local_lock_irqsave(crngs_lock, flags);
+	local_irq_save(flags);
 	crng = raw_cpu_ptr(&crngs);
 
 	/*
@@ -389,7 +387,7 @@ static void crng_make_state(u32 chacha_state[CHACHA20_BLOCK_SIZE / sizeof(u32)],
 	 * should wind up here immediately.
 	 */
 	crng_fast_key_erasure(crng->key, chacha_state, random_data, random_data_len);
-	local_unlock_irqrestore(crngs_lock, flags);
+	local_irq_restore(flags);
 }
 
 static void _get_random_bytes(void *buf, size_t len)
@@ -514,7 +512,6 @@ struct batch_ ##type {								\
 static DEFINE_PER_CPU(struct batch_ ##type, batched_entropy_ ##type) = {	\
 	.position = UINT_MAX							\
 };										\
-static DEFINE_LOCAL_IRQ_LOCK(batched_entropy_lock_ ##type);			\
 										\
 type get_random_ ##type(void)							\
 {										\
@@ -530,7 +527,7 @@ type get_random_ ##type(void)							\
 		return ret;							\
 	}									\
 										\
-	local_lock_irqsave(batched_entropy_lock_ ##type, flags);		\
+	local_irq_save(flags);		\
 	batch = raw_cpu_ptr(&batched_entropy_##type);				\
 										\
 	next_gen = READ_ONCE(base_crng.generation);				\
@@ -544,7 +541,7 @@ type get_random_ ##type(void)							\
 	ret = batch->entropy[batch->position];					\
 	batch->entropy[batch->position] = 0;					\
 	++batch->position;							\
-	local_unlock_irqrestore(batched_entropy_lock_ ##type, flags);		\
+	local_irq_restore(flags);		\
 	return ret;								\
 }										\
 EXPORT_SYMBOL(get_random_ ##type);
-- 
2.38.0