Re: [PATCH] [v2] enic: fix build warning without CONFIG_CPUMASK_OFFSTACK

[Nathan Chancellor <natechancellor@gmail.com>]

On Thu, Mar 07, 2019 at 04:52:24PM +0100, Arnd Bergmann wrote:
> The enic driver relies on the CONFIG_CPUMASK_OFFSTACK feature to
> dynamically allocate a struct member, but this is normally intended for
> local variables.
> 
> Building with clang, I get a warning for a few locations that check the
> address of the cpumask_var_t:
> 
> drivers/net/ethernet/cisco/enic/enic_main.c:122:22: error: address of array 'enic->msix[i].affinity_mask' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
> 
> As far as I can tell, the code is still correct, as the truth value of
> the pointer is what we need in this configuration. To get rid of
> the warning, use cpumask_available() instead of checking the
> pointer directly.
> 
> Fixes: 322cf7e3a4e8 ("enic: assign affinity hint to interrupts")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

> ---
> v2: use cpumask_available() instead of open-coding a copy
> ---
>  drivers/net/ethernet/cisco/enic/enic_main.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
> index 9a7f70db20c7..733d9172425b 100644
> --- a/drivers/net/ethernet/cisco/enic/enic_main.c
> +++ b/drivers/net/ethernet/cisco/enic/enic_main.c
> @@ -119,7 +119,7 @@ static void enic_init_affinity_hint(struct enic *enic)
>  
>  	for (i = 0; i < enic->intr_count; i++) {
>  		if (enic_is_err_intr(enic, i) || enic_is_notify_intr(enic, i) ||
> -		    (enic->msix[i].affinity_mask &&
> +		    (cpumask_available(enic->msix[i].affinity_mask) &&
>  		     !cpumask_empty(enic->msix[i].affinity_mask)))
>  			continue;
>  		if (zalloc_cpumask_var(&enic->msix[i].affinity_mask,
> @@ -148,7 +148,7 @@ static void enic_set_affinity_hint(struct enic *enic)
>  	for (i = 0; i < enic->intr_count; i++) {
>  		if (enic_is_err_intr(enic, i)		||
>  		    enic_is_notify_intr(enic, i)	||
> -		    !enic->msix[i].affinity_mask	||
> +		    !cpumask_available(enic->msix[i].affinity_mask) ||
>  		    cpumask_empty(enic->msix[i].affinity_mask))
>  			continue;
>  		err = irq_set_affinity_hint(enic->msix_entry[i].vector,
> @@ -161,7 +161,7 @@ static void enic_set_affinity_hint(struct enic *enic)
>  	for (i = 0; i < enic->wq_count; i++) {
>  		int wq_intr = enic_msix_wq_intr(enic, i);
>  
> -		if (enic->msix[wq_intr].affinity_mask &&
> +		if (cpumask_available(enic->msix[wq_intr].affinity_mask) &&
>  		    !cpumask_empty(enic->msix[wq_intr].affinity_mask))
>  			netif_set_xps_queue(enic->netdev,
>  					    enic->msix[wq_intr].affinity_mask,
> -- 
> 2.20.0
>