linux-kernel - [PATCH 15/15] random: vDSO: remove ifdeffery

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Message-Id: <20260114-vdso-header-cleanups-v1-15-803b80ee97b4@linutronix.de>
Date: Wed, 14 Jan 2026 09:01:47 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Catalin Marinas <catalin.marinas@....com>, 
 Will Deacon <will@...nel.org>, Russell King <linux@...linux.org.uk>, 
 Madhavan Srinivasan <maddy@...ux.ibm.com>, 
 Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
 "Christophe Leroy (CS GROUP)" <chleroy@...nel.org>, 
 Huacai Chen <chenhuacai@...nel.org>, WANG Xuerui <kernel@...0n.name>, 
 Thomas Bogendoerfer <tsbogend@...ha.franken.de>, 
 Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...nel.org>, 
 Vincenzo Frascino <vincenzo.frascino@....com>, 
 Theodore Ts'o <tytso@....edu>, "Jason A. Donenfeld" <Jason@...c4.com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 linuxppc-dev@...ts.ozlabs.org, loongarch@...ts.linux.dev, 
 linux-mips@...r.kernel.org, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH 15/15] random: vDSO: remove ifdeffery

Recent cleanups of the vDSO headers allow the unconditional inclusion of
vdso/datapage.h and the declarations it provides. This also means that
the declaration of vdso_k_rng_data is always visible and its usage does
not need to be guarded by ifdefs anymore. Instead use IS_ENABLED().

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 drivers/char/random.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index c5122ff33594..64f709fdf434 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -56,9 +56,7 @@
 #include <linux/sched/isolation.h>
 #include <crypto/chacha.h>
 #include <crypto/blake2s.h>
-#ifdef CONFIG_VDSO_GETRANDOM
 #include <vdso/datapage.h>
-#endif
 #include <asm/archrandom.h>
 #include <asm/processor.h>
 #include <asm/irq.h>
@@ -274,7 +272,7 @@ static void crng_reseed(struct work_struct *work)
 	if (next_gen == ULONG_MAX)
 		++next_gen;
 	WRITE_ONCE(base_crng.generation, next_gen);
-#ifdef CONFIG_VDSO_GETRANDOM
+
 	/* base_crng.generation's invalid value is ULONG_MAX, while
 	 * vdso_k_rng_data->generation's invalid value is 0, so add one to the
 	 * former to arrive at the latter. Use smp_store_release so that this
@@ -288,8 +286,9 @@ static void crng_reseed(struct work_struct *work)
 	 * because the vDSO side only checks whether the value changed, without
 	 * actually using or interpreting the value.
 	 */
-	smp_store_release((unsigned long *)&vdso_k_rng_data->generation, next_gen + 1);
-#endif
+	if (IS_ENABLED(CONFIG_VDSO_GETRANDOM))
+		smp_store_release((unsigned long *)&vdso_k_rng_data->generation, next_gen + 1);
+
 	if (!static_branch_likely(&crng_is_ready))
 		crng_init = CRNG_READY;
 	spin_unlock_irqrestore(&base_crng.lock, flags);
@@ -742,9 +741,8 @@ static void __cold _credit_init_bits(size_t bits)
 		if (system_dfl_wq)
 			queue_work(system_dfl_wq, &set_ready);
 		atomic_notifier_call_chain(&random_ready_notifier, 0, NULL);
-#ifdef CONFIG_VDSO_GETRANDOM
-		WRITE_ONCE(vdso_k_rng_data->is_ready, true);
-#endif
+		if (IS_ENABLED(CONFIG_VDSO_GETRANDOM))
+			WRITE_ONCE(vdso_k_rng_data->is_ready, true);
 		wake_up_interruptible(&crng_init_wait);
 		kill_fasync(&fasync, SIGIO, POLL_IN);
 		pr_notice("crng init done\n");

-- 
2.52.0