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    Subject[PATCH 4.9 088/264] random: use IS_ENABLED(CONFIG_NUMA) instead of ifdefs
    Date
    From: "Jason A. Donenfeld" <Jason@zx2c4.com>

    commit 7b87324112df2e1f9b395217361626362dcfb9fb upstream.

    Rather than an awkward combination of ifdefs and __maybe_unused, we can
    ensure more source gets parsed, regardless of the configuration, by
    using IS_ENABLED for the CONFIG_NUMA conditional code. This makes things
    cleaner and easier to follow.

    I've confirmed that on !CONFIG_NUMA, we don't wind up with excess code
    by accident; the generated object file is the same.

    Reviewed-by: 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 | 32 ++++++++++++--------------------
    1 file changed, 12 insertions(+), 20 deletions(-)

    --- a/drivers/char/random.c
    +++ b/drivers/char/random.c
    @@ -762,7 +762,6 @@ static int credit_entropy_bits_safe(stru

    static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);

    -#ifdef CONFIG_NUMA
    /*
    * Hack to deal with crazy userspace progams when they are all trying
    * to access /dev/urandom in parallel. The programs are almost
    @@ -770,7 +769,6 @@ static DECLARE_WAIT_QUEUE_HEAD(crng_init
    * their brain damage.
    */
    static struct crng_state **crng_node_pool __read_mostly;
    -#endif

    static void invalidate_batched_entropy(void);

    @@ -817,7 +815,7 @@ static bool __init crng_init_try_arch_ea
    return arch_init;
    }

    -static void __maybe_unused crng_initialize_secondary(struct crng_state *crng)
    +static void crng_initialize_secondary(struct crng_state *crng)
    {
    memcpy(&crng->state[0], "expand 32-byte k", 16);
    _get_random_bytes(&crng->state[4], sizeof(__u32) * 12);
    @@ -868,7 +866,6 @@ static void crng_finalize_init(struct cr
    }
    }

    -#ifdef CONFIG_NUMA
    static void do_numa_crng_init(struct work_struct *work)
    {
    int i;
    @@ -895,29 +892,24 @@ static DECLARE_WORK(numa_crng_init_work,

    static void numa_crng_init(void)
    {
    - schedule_work(&numa_crng_init_work);
    + if (IS_ENABLED(CONFIG_NUMA))
    + schedule_work(&numa_crng_init_work);
    }

    static struct crng_state *select_crng(void)
    {
    - struct crng_state **pool;
    - int nid = numa_node_id();
    -
    - /* pairs with cmpxchg_release() in do_numa_crng_init() */
    - pool = READ_ONCE(crng_node_pool);
    - if (pool && pool[nid])
    - return pool[nid];
    -
    - return &primary_crng;
    -}
    -#else
    -static void numa_crng_init(void) {}
    + if (IS_ENABLED(CONFIG_NUMA)) {
    + struct crng_state **pool;
    + int nid = numa_node_id();
    +
    + /* pairs with cmpxchg_release() in do_numa_crng_init() */
    + pool = READ_ONCE(crng_node_pool);
    + if (pool && pool[nid])
    + return pool[nid];
    + }

    -static struct crng_state *select_crng(void)
    -{
    return &primary_crng;
    }
    -#endif

    /*
    * crng_fast_load() can be called by code in the interrupt service

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