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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Dominik Brodowski <linux@dominikbrodowski.net>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH 5.15 241/247] random: avoid checking crng_ready() twice in random_init()
Date:   Mon, 13 Jun 2022 12:12:23 +0200
Message-Id: <20220613094930.257227164@linuxfoundation.org>
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From: "Jason A. Donenfeld" <Jason@zx2c4.com>

commit 9b29b6b20376ab64e1b043df6301d8a92378e631 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/random.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -838,7 +838,7 @@ int __init random_init(const char *comma
 	if (crng_ready())
 		crng_reseed();
 	else if (trust_cpu)
-		credit_init_bits(arch_bytes * 8);
+		_credit_init_bits(arch_bytes * 8);
 
 	return 0;
 }