Re: [PATCH v6 5/7] bus: add helper to handle sigbus

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 09.07.2018 09:01, Jeff Guo wrote:
> This patch aim to add a helper to iterate all buses to find the
> corresponding bus to handle the sigbus error.
>
> Signed-off-by: Jeff Guo <jia.guo@intel.com>
> Acked-by: Shaopeng He <shaopeng.he@intel.com>
> ---
> v6->v5:
> refine some coding style.
> ---
>   lib/librte_eal/common/eal_common_bus.c | 42 ++++++++++++++++++++++++++++++++++
>   lib/librte_eal/common/eal_private.h    | 12 ++++++++++
>   2 files changed, 54 insertions(+)
>
> diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
> index 0943851..8856adc 100644
> --- a/lib/librte_eal/common/eal_common_bus.c
> +++ b/lib/librte_eal/common/eal_common_bus.c
> @@ -37,6 +37,7 @@
>   #include <rte_bus.h>
>   #include <rte_debug.h>
>   #include <rte_string_fns.h>
> +#include <rte_errno.h>
>   
>   #include "eal_private.h"
>   
> @@ -242,3 +243,44 @@ rte_bus_get_iommu_class(void)
>   	}
>   	return mode;
>   }
> +
> +static int
> +bus_handle_sigbus(const struct rte_bus *bus,
> +			const void *failure_addr)
> +{
> +	int ret;
> +
> +	if (!bus->sigbus_handler) {
> +		RTE_LOG(ERR, EAL, "Function sigbus_handler not supported by "
> +			"bus (%s)\n", bus->name);
> +		return -1;
> +	}
> +
> +	ret = bus->sigbus_handler(failure_addr);
> +	rte_errno = ret;
> +
> +	return !(bus->sigbus_handler && ret <= 0);

Since bus->sigbus_handler is checked above, there is no point to check 
it here.

> +}
> +
> +int
> +rte_bus_sigbus_handler(const void *failure_addr)
> +{
> +	struct rte_bus *bus;
> +
> +	int ret = 0;
> +	int old_errno = rte_errno;
> +
> +	rte_errno = 0;
> +
> +	bus = rte_bus_find(NULL, bus_handle_sigbus, failure_addr);
> +	/* failed to handle the sigbus, pass the new errno. */
> +	if (!bus)
> +		ret = 1;
> +	else if (rte_errno == -1)

Is it OK to preserve negative value in rte_errno here? I think no.
rte_errno should have value from corresponding set of errno values.

> +		return -1;
> +
> +	/* otherwise restore the old errno. */
> +	rte_errno = old_errno;
> +
> +	return ret;
> +}
> diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
> index bdadc4d..2337e71 100644
> --- a/lib/librte_eal/common/eal_private.h
> +++ b/lib/librte_eal/common/eal_private.h
> @@ -258,4 +258,16 @@ int rte_mp_channel_init(void);
>    */
>   void dev_callback_process(char *device_name, enum rte_dev_event_type event);
>   
> +/**
> + * Iterate all buses to find the corresponding bus, to handle the sigbus error.
> + * @param failure_addr
> + *	Pointer of the fault address of the sigbus error.
> + *
> + * @return
> + *	 0 success to handle the sigbus.
> + *	-1 failed to handle the sigbus
> + *	 1 no bus can handler the sigbus
> + */
> +int rte_bus_sigbus_handler(const void *failure_addr);
> +
>   #endif /* _EAL_PRIVATE_H_ */