The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9b29b6b20376ab64e1b043df6301d8a92378e631 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Jason@zx2c4.com Date: Tue, 7 Jun 2022 09:44:07 +0200 Subject: [PATCH] random: avoid checking crng_ready() twice in random_init()
The current flow expands to:
if (crng_ready()) ... else if (...) if (!crng_ready()) ...
The second crng_ready() call is redundant, but can't so easily be optimized out by the compiler.
This commit simplifies that to:
if (crng_ready() ... else if (...) ...
Fixes: 560181c27b58 ("random: move initialization functions out of hot pages") Cc: stable@vger.kernel.org Cc: Dominik Brodowski linux@dominikbrodowski.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com
diff --git a/drivers/char/random.c b/drivers/char/random.c index b691b9d59503..4862d4d3ec49 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -801,7 +801,7 @@ int __init random_init(const char *command_line) if (crng_ready()) crng_reseed(); else if (trust_cpu) - credit_init_bits(arch_bytes * 8); + _credit_init_bits(arch_bytes * 8); used_arch_random = arch_bytes * 8 >= POOL_READY_BITS;
WARN_ON(register_pm_notifier(&pm_notifier));