random: Avoid open-coded use of ratelimit_state structure's ->missed field

The _credit_init_bits() function directly accesses the ratelimit_state
structure's ->missed field, which works, but which also makes it
more difficult to change this field.  Therefore, make use of the
ratelimit_state_get_miss() and ratelimit_state_inc_miss() functions
instead of directly accessing the ->missed field.

Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
"Jason A. Donenfeld" <Jason@zx2c4.com>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 38f2fab29c569cb92318e8dc1085a63848611eea..416dac0ab565d7bb27d7621ce0bc16cbff620a27 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -726,6 +726,7 @@ static void __cold _credit_init_bits(size_t bits)
        static DECLARE_WORK(set_ready, crng_set_ready);
        unsigned int new, orig, add;
        unsigned long flags;
+       int m;
 
        if (!bits)
                return;
@@ -748,9 +749,9 @@ static void __cold _credit_init_bits(size_t bits)
                wake_up_interruptible(&crng_init_wait);
                kill_fasync(&fasync, SIGIO, POLL_IN);
                pr_notice("crng init done\n");
-               if (urandom_warning.missed)
-                       pr_notice("%d urandom warning(s) missed due to ratelimiting\n",
-                                 urandom_warning.missed);
+               m = ratelimit_state_get_miss(&urandom_warning);
+               if (m)
+                       pr_notice("%d urandom warning(s) missed due to ratelimiting\n", m);
        } else if (orig < POOL_EARLY_BITS && new >= POOL_EARLY_BITS) {
                spin_lock_irqsave(&base_crng.lock, flags);
                /* Check if crng_init is CRNG_EMPTY, to avoid race with crng_reseed(). */
@@ -1466,7 +1467,7 @@ static ssize_t urandom_read_iter(struct kiocb *kiocb, struct iov_iter *iter)
 
        if (!crng_ready()) {
                if (!ratelimit_disable && maxwarn <= 0)
-                       ++urandom_warning.missed;
+                       ratelimit_state_inc_miss(&urandom_warning);
                else if (ratelimit_disable || __ratelimit(&urandom_warning)) {
                        --maxwarn;
                        pr_notice("%s: uninitialized urandom read (%zu bytes read)\n",