random: If we have arch_get_random_seed*(), try it before blocking

}

#endif

/*

 * Attempt an emergency refill using arch_get_random_seed_long().

 *

 * As with add_interrupt_randomness() be paranoid and only

 * credit the output as 50% entropic.

 */

static int arch_random_refill(void)

{

	const unsigned int nlongs = 64;	/* Arbitrary number */

	unsigned int n = 0;

	unsigned int i;

	unsigned long buf[nlongs];

	for (i = 0; i < nlongs; i++) {

		if (arch_get_random_seed_long(&buf[n]))

			n++;

	}

	if (n) {

		unsigned int rand_bytes = n * sizeof(unsigned long);

		mix_pool_bytes(&input_pool, buf, rand_bytes, NULL);

		credit_entropy_bits(&input_pool, rand_bytes*4);

	}

	return n;

}

static ssize_t

random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)

{

				  ENTROPY_BITS(&input_pool));

		if (n > 0)

			return n;

		/* Pool is (near) empty.  Maybe wait and retry. */

		/* First try an emergency refill */

		if (arch_random_refill())

			continue;

		if (file->f_flags & O_NONBLOCK)

			return -EAGAIN;