Re: [lttng-dev] [PATCH 7/7] Fix: uatomic_or() need retyping to uintptr_t in rculfhash.c

[Mathieu Desnoyers via lttng-dev <lttng-dev@lists.lttng.org>]

On 2023-03-21 10:51, Ondřej Surý via lttng-dev wrote:
> When adding REMOVED_FLAG to the pointers in the rculfhash
> implementation, retype the generic pointer to unsigned long to fix the
> following compiler error:

You will need to update the patch subject as well.

Thanks,

Mathieu

> 
> rculfhash.c:1201:2: error: address argument to atomic operation must be a pointer to integer ('struct cds_lfht_node **' invalid)
>         uatomic_or(&node->next, REMOVED_FLAG);
>         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../include/urcu/uatomic.h:60:8: note: expanded from macro 'uatomic_or'
>         (void)__atomic_or_fetch((addr), (mask), __ATOMIC_RELAXED)
>               ^                 ~~~~~~
> rculfhash.c:1444:3: error: address argument to atomic operation must be a pointer to integer ('struct cds_lfht_node **' invalid)
>                 uatomic_or(&fini_bucket->next, REMOVED_FLAG);
>                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../include/urcu/uatomic.h:60:8: note: expanded from macro 'uatomic_or'
>         (void)__atomic_or_fetch((addr), (mask), __ATOMIC_RELAXED)
>               ^                 ~~~~~~
> 
> This was not a problem before because the way the uatomic_or was
> implemented, but now we directly pass the addr to __atomic_or_fetch()
> and the compiler doesn't like the implicit conversion from pointer to
> pointer to integer.
> 
> Signed-off-by: Ondřej Surý <ondrej@sury.org>
> ---
>   src/rculfhash.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/rculfhash.c b/src/rculfhash.c
> index b456415..5292725 100644
> --- a/src/rculfhash.c
> +++ b/src/rculfhash.c
> @@ -1198,7 +1198,7 @@ int _cds_lfht_del(struct cds_lfht *ht, unsigned long size,
>   	 * Knowing which wins the race will be known after the garbage
>   	 * collection phase, stay tuned!
>   	 */
> -	uatomic_or(&node->next, REMOVED_FLAG);
> +	uatomic_or((unsigned long *)&node->next, REMOVED_FLAG);
>   	/* We performed the (logical) deletion. */
>   
>   	/*
> @@ -1441,7 +1441,7 @@ void remove_table_partition(struct cds_lfht *ht, unsigned long i,
>   		dbg_printf("remove entry: order %lu index %lu hash %lu\n",
>   			   i, j, j);
>   		/* Set the REMOVED_FLAG to freeze the ->next for gc */
> -		uatomic_or(&fini_bucket->next, REMOVED_FLAG);
> +		uatomic_or((unsigned long *)&fini_bucket->next, REMOVED_FLAG);
>   		_cds_lfht_gc_bucket(parent_bucket, fini_bucket);
>   	}
>   	ht->flavor->read_unlock();

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com

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