[PATCH v3] lib/ring: do not allow zero size ring

[Konstantin Ananyev]

> this might happen when for instance the ring size is read from
> config, and would cause runtime crash. Do so by using the
> RTE_IS_POWER_OF_2 macro.
> 
> Signed-off-by: Isaac Boukris <iboukris at gmail.com>
> Acked-by: Wathsala Vithanage <wathsala.vithanage at arm.com>
> Acked-by: Morten Brørup <mb at smartsharesystems.com>
> ---
> 
> v3:
> * changed to use the RTE_IS_POWER_OF_2 macro.
> 
> v2:
> * move the fix to the POWEROF2 macro itself.
> * fixed style in the test code.
> 
>  app/test/test_ring.c | 7 +++++++
>  lib/ring/rte_ring.c  | 8 +++-----
>  2 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/app/test/test_ring.c b/app/test/test_ring.c
> index ba1fec1de3..3078348b2f 100644
> --- a/app/test/test_ring.c
> +++ b/app/test/test_ring.c
> @@ -505,6 +505,13 @@ test_ring_negative_tests(void)
>  	struct rte_ring *rt = NULL;
>  	unsigned int i;
> 
> +	/* Test zero size ring */
> +	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
> +	if (rp != NULL) {
> +		printf("Test failed to detect zero size ring\n");
> +		goto test_fail;
> +	}
> +
>  	/* Test with esize not a multiple of 4 */
>  	rp = test_ring_create("test_bad_element_size", 23,
>  				RING_SIZE + 1, SOCKET_ID_ANY, 0);
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index edd63aa535..f10050a1c4 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -25,6 +25,7 @@
>  #include <rte_string_fns.h>
>  #include <rte_tailq.h>
>  #include <rte_telemetry.h>
> +#include <rte_bitops.h>
> 
>  #include "rte_ring.h"
>  #include "rte_ring_elem.h"
> @@ -46,9 +47,6 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
>  		     RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ |	       \
>  		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
> 
> -/* true if x is a power of 2 */
> -#define POWEROF2(x) ((((x)-1) & (x)) == 0)
> -
>  /* by default set head/tail distance as 1/8 of ring capacity */
>  #define HTD_MAX_DEF	8
> 
> @@ -67,7 +65,7 @@ rte_ring_get_memsize_elem(unsigned int esize, unsigned int
> count)
>  	}
> 
>  	/* count must be a power of 2 */
> -	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
> +	if ((!RTE_IS_POWER_OF_2(count)) || (count > RTE_RING_SZ_MASK)) {
>  		RING_LOG(ERR,
>  			"Requested number of elements is invalid, must be power of
> 2, and not exceed %u",
>  			RTE_RING_SZ_MASK);
> @@ -227,7 +225,7 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned
> int count,
>  		r->mask = r->size - 1;
>  		r->capacity = count;
>  	} else {
> -		if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {
> +		if ((!RTE_IS_POWER_OF_2(count)) || (count > RTE_RING_SZ_MASK))
> {
>  			RING_LOG(ERR,
>  				"Requested size is invalid, must be power of 2, and
> not exceed the size limit %u",
>  				RTE_RING_SZ_MASK);
> --

Acked-by: Konstantin Ananyev <konstantin.ananyev at huawei.com>

> 2.49.0