Re: [dpdk-dev] [PATCH] cryptodev: fix invalid dev_id after a pmd close

[Akhil Goyal <akhil.goyal@nxp.com>]

Hi Julien

> 
> Each cryptodev are indexed with its dev_id in the global
> rte_crypto_devices variable. nb_devs is incremented / decremented each
> time a cryptodev is created / deleted. The goal of nb_devs is to prevent
> the user to get an invalid dev_id.
> 
> Let's imagine DPDK has configured N cryptodevs. If the cryptodev=1 is
> removed at runtime, the latest cryptodev N cannot be accessible, because
> nb_devs=N-1.
> 
> In order to prevent this kind of behavior, let's remove the check with
> nb_devs and iterate in all the rte_crypto_devices elements: if data is
> not NULL, that means a valid cryptodev is available.
> 
> Fixes: d11b0f30df88 ("cryptodev: introduce API and framework for crypto
> devices")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Julien Meunier <julien.meunier@nokia.com>
> ---
>  lib/librte_cryptodev/rte_cryptodev.c | 42 ++++++++++++++++++++++++----------
> --
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/lib/librte_cryptodev/rte_cryptodev.c
> b/lib/librte_cryptodev/rte_cryptodev.c
> index 43bc335..c8c7ffd 100644
> --- a/lib/librte_cryptodev/rte_cryptodev.c
> +++ b/lib/librte_cryptodev/rte_cryptodev.c
> @@ -49,9 +49,7 @@ struct rte_cryptodev *rte_cryptodevs = rte_crypto_devices;
> 
>  static struct rte_cryptodev_global cryptodev_globals = {
>  		.devs			= rte_crypto_devices,
> -		.data			= { NULL },
> -		.nb_devs		= 0,
> -		.max_devs		= RTE_CRYPTO_MAX_DEVS
> +		.data			= { NULL }
>  };
> 
>  /* spinlock for crypto device callbacks */
> @@ -512,7 +510,7 @@ rte_cryptodev_pmd_get_named_dev(const char *name)
>  	if (name == NULL)
>  		return NULL;
> 
> -	for (i = 0; i < cryptodev_globals.max_devs; i++) {
> +	for (i = 0; i < RTE_CRYPTO_MAX_DEVS; i++) {
>  		dev = &cryptodev_globals.devs[i];
> 
>  		if ((dev->attached == RTE_CRYPTODEV_ATTACHED) &&
> @@ -523,12 +521,21 @@ rte_cryptodev_pmd_get_named_dev(const char
> *name)
>  	return NULL;
>  }
> 
> +static uint8_t
> +rte_cryptodev_is_valid_device_data(uint8_t dev_id)
> +{
> +	if (rte_crypto_devices[dev_id].data == NULL)
> +		return 0;
> +
> +	return 1;
> +}
> +
>  unsigned int
>  rte_cryptodev_pmd_is_valid_dev(uint8_t dev_id)
>  {
>  	struct rte_cryptodev *dev = NULL;
> 
> -	if (dev_id >= cryptodev_globals.nb_devs)
> +	if (!rte_cryptodev_is_valid_device_data(dev_id))
>  		return 0;
> 
>  	dev = rte_cryptodev_pmd_get_dev(dev_id);
> @@ -547,12 +554,15 @@ rte_cryptodev_get_dev_id(const char *name)
>  	if (name == NULL)
>  		return -1;
> 
> -	for (i = 0; i < cryptodev_globals.nb_devs; i++)
> +	for (i = 0; i < RTE_CRYPTO_MAX_DEVS; i++) {
> +		if (!rte_cryptodev_is_valid_device_data(i))
> +			continue;
>  		if ((strcmp(cryptodev_globals.devs[i].data->name, name)
>  				== 0) &&
>  				(cryptodev_globals.devs[i].attached ==
>  						RTE_CRYPTODEV_ATTACHED))
>  			return i;
> +	}
> 
>  	return -1;
>  }
> @@ -560,7 +570,13 @@ rte_cryptodev_get_dev_id(const char *name)
>  uint8_t
>  rte_cryptodev_count(void)
>  {
> -	return cryptodev_globals.nb_devs;
> +	uint8_t i, dev_count = 0;
> +
> +	for (i = 0; i < RTE_CRYPTO_MAX_DEVS; i++)
> +		if (cryptodev_globals.devs[i].data != NULL)
> +			dev_count++;
> +
> +	return dev_count;
>  }

Why do you want to remove the nb_devs? We can have it updated (incremented/decremented)
While allocate/release of the device.
The point is, whenever somebody call rte_cryptodev_count() it will do a lookup of valid data
pointer.

> 
>  uint8_t
> @@ -568,7 +584,7 @@ rte_cryptodev_device_count_by_driver(uint8_t
> driver_id)
>  {
>  	uint8_t i, dev_count = 0;
> 
> -	for (i = 0; i < cryptodev_globals.max_devs; i++)
> +	for (i = 0; i < RTE_CRYPTO_MAX_DEVS; i++)
>  		if (cryptodev_globals.devs[i].driver_id == driver_id &&
>  			cryptodev_globals.devs[i].attached ==
>  					RTE_CRYPTODEV_ATTACHED)
> @@ -583,9 +599,10 @@ rte_cryptodev_devices_get(const char *driver_name,
> uint8_t *devices,
>  {
>  	uint8_t i, count = 0;
>  	struct rte_cryptodev *devs = cryptodev_globals.devs;
> -	uint8_t max_devs = cryptodev_globals.max_devs;
> 
> -	for (i = 0; i < max_devs && count < nb_devices;	i++) {
> +	for (i = 0; i < RTE_CRYPTO_MAX_DEVS && count < nb_devices; i++) {
> +		if (!rte_cryptodev_is_valid_device_data(i))
> +			continue;
> 
>  		if (devs[i].attached == RTE_CRYPTODEV_ATTACHED) {
>  			int cmp;
> @@ -736,8 +753,6 @@ rte_cryptodev_pmd_allocate(const char *name, int
> socket_id)
>  		TAILQ_INIT(&(cryptodev->link_intr_cbs));
> 
>  		cryptodev->attached = RTE_CRYPTODEV_ATTACHED;
> -
> -		cryptodev_globals.nb_devs++;
>  	}
> 
>  	return cryptodev;
> @@ -766,7 +781,6 @@ rte_cryptodev_pmd_release_device(struct
> rte_cryptodev *cryptodev)
>  		return ret;
> 
>  	cryptodev->attached = RTE_CRYPTODEV_DETACHED;
> -	cryptodev_globals.nb_devs--;
>  	return 0;
>  }
> 
> @@ -1099,7 +1113,7 @@ rte_cryptodev_info_get(uint8_t dev_id, struct
> rte_cryptodev_info *dev_info)
>  {
>  	struct rte_cryptodev *dev;
> 
> -	if (dev_id >= cryptodev_globals.nb_devs) {
> +	if (!rte_cryptodev_pmd_is_valid_dev(dev_id)) {
>  		CDEV_LOG_ERR("Invalid dev_id=%d", dev_id);
>  		return;
>  	}
> --
> 2.10.2