[Intel-gfx] [PATCH v4 04/38] lib: Add a simple prime number generator

[Joonas Lahtinen]

On to, 2016-12-22 at 08:36 +0000, Chris Wilson wrote:
> Prime numbers are interesting for testing components that use multiplies
> and divides, such as testing DRM's struct drm_mm alignment computations.
> 
> v2: Move to lib/, add selftest
> v3: Fix initial constants (exclude 0/1 from being primes)
> v4: More RCU markup to keep 0day/sparse happy
> v5: Fix RCU unwind on module exit, add to kselftests
> v6: Tidy computation of bitmap size
> v7: for_each_prime_number_from()
> v8: Compose small-primes using BIT() for easier verification
> v9: Move rcu dance entirely into callers.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Lukas Wunner <lukas at wunner.de>

<SNIP>

> +static bool expand_to_next_prime(unsigned long x)
> +{
> +	const struct primes *p;
> +	struct primes *new;
> +	unsigned long sz, y;
> +
> +	/* Betrand's Theorem states:

"From Bertrand's postulate:"

> +	 * 	For all n > 1, there exists a prime p: n < p <= 2*n.

"n < p < 2*n"

> +	 */
> +	sz = 2 * x + 1;

And I'd also drop the + 1, not that it matters much.

Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation