[PATCH] net/failsafe: fix interrupt handle leak

[Ferruh Yigit]

On 3/24/2022 3:09 PM, David Marchand wrote:
> A intr_handle is being allocated as a hack to get a (proxy) eventfd from
> the Linux interrupt implementation.
> But this handle is never freed.
> 
> Remove this convoluted hack and create an eventfd in Linux case.
> 
> Fixes: d61138d4f0e2 ("drivers: remove direct access to interrupt handle")
> Cc: stable at dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand at redhat.com>
> ---
>   drivers/net/failsafe/failsafe_ops.c | 32 ++++++++++-------------------
>   1 file changed, 11 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/net/failsafe/failsafe_ops.c b/drivers/net/failsafe/failsafe_ops.c
> index 55e21d635c..2c23d0e70a 100644
> --- a/drivers/net/failsafe/failsafe_ops.c
> +++ b/drivers/net/failsafe/failsafe_ops.c
> @@ -6,6 +6,9 @@
>   #include <stdbool.h>
>   #include <stdint.h>
>   #include <unistd.h>
> +#ifdef RTE_EXEC_ENV_LINUX
> +#include <sys/eventfd.h>
> +#endif
>   
>   #include <rte_debug.h>
>   #include <rte_atomic.h>
> @@ -387,28 +390,11 @@ fs_rx_queue_setup(struct rte_eth_dev *dev,
>   		const struct rte_eth_rxconf *rx_conf,
>   		struct rte_mempool *mb_pool)
>   {
> -	/*
> -	 * FIXME: Add a proper interface in rte_eal_interrupts for
> -	 * allocating eventfd as an interrupt vector.
> -	 * For the time being, fake as if we are using MSIX interrupts,
> -	 * this will cause rte_intr_efd_enable to allocate an eventfd for us.
> -	 */
> -	struct rte_intr_handle *intr_handle;
>   	struct sub_device *sdev;
>   	struct rxq *rxq;
>   	uint8_t i;
>   	int ret;
>   
> -	intr_handle = rte_intr_instance_alloc(RTE_INTR_INSTANCE_F_PRIVATE);
> -	if (intr_handle == NULL)
> -		return -ENOMEM;
> -
> -	if (rte_intr_type_set(intr_handle, RTE_INTR_HANDLE_VFIO_MSIX))
> -		return -rte_errno;
> -
> -	if (rte_intr_efds_index_set(intr_handle, 0, -1))
> -		return -rte_errno;
> -
>   	fs_lock(dev, 0);
>   	if (rx_conf->rx_deferred_start) {
>   		FOREACH_SUBDEV_STATE(sdev, i, dev, DEV_PROBED) {
> @@ -442,12 +428,16 @@ fs_rx_queue_setup(struct rte_eth_dev *dev,
>   	rxq->info.nb_desc = nb_rx_desc;
>   	rxq->priv = PRIV(dev);
>   	rxq->sdev = PRIV(dev)->subs;
> -	ret = rte_intr_efd_enable(intr_handle, 1);
> -	if (ret < 0) {
> +#ifdef RTE_EXEC_ENV_LINUX
> +	rxq->event_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
> +	if (rxq->event_fd < 0) {
> +		ERROR("Failed to create an eventfd: %s", strerror(errno));
>   		fs_unlock(dev, 0);
> -		return ret;
> +		return -errno;
>   	}
> -	rxq->event_fd = rte_intr_efds_index_get(intr_handle, 0);
> +#else
> +	rxq->event_fd = -1;
> +#endif

How this impacts the BSD? I don't know if driver used on BSD but 
technically it looks supported.

@Gaetan, any objection to the change?