Re: [PATCH V5 1/3] driver core: add device_has_managed_msi_irq

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Jul 21, 2021 at 05:17:21PM +0800, Ming Lei wrote:
> irq vector allocation with managed affinity may be used by driver, and
> blk-mq needs this info for draining queue because genirq core will shutdown
> managed irq when all CPUs in the affinity mask are offline.
> 
> The info of using managed irq is often produced by drivers, and it is
> consumed by blk-mq, so different subsystems are involved in this info flow.
> 
> Address this issue by adding one helper of device_has_managed_msi_irq()
> which is suggested by John Garry.
> 
> Suggested-by: John Garry <john.garry@huawei.com>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  drivers/base/core.c    | 15 +++++++++++++++
>  include/linux/device.h |  2 ++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index cadcade65825..41daf9fabdfb 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -29,6 +29,7 @@
>  #include <linux/sched/mm.h>
>  #include <linux/sysfs.h>
>  #include <linux/dma-map-ops.h> /* for dma_default_coherent */
> +#include <linux/msi.h> /* for device_has_managed_irq */
>  
>  #include "base.h"
>  #include "power/power.h"
> @@ -4797,3 +4798,17 @@ int device_match_any(struct device *dev, const void *unused)
>  	return 1;
>  }
>  EXPORT_SYMBOL_GPL(device_match_any);
> +
> +bool device_has_managed_msi_irq(struct device *dev)
> +{
> +	struct msi_desc *desc;
> +
> +	if (IS_ENABLED(CONFIG_GENERIC_MSI_IRQ)) {
> +		for_each_msi_entry(desc, dev) {
> +			if (desc->affinity && desc->affinity->is_managed)
> +				return true;
> +		}
> +	}
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(device_has_managed_msi_irq);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 59940f1744c1..b1255524ce8b 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -981,4 +981,6 @@ extern long sysfs_deprecated;
>  #define sysfs_deprecated 0
>  #endif
>  
> +bool device_has_managed_msi_irq(struct device *dev);

This really belongs in msi.h, not device.h, as it is very MSI specific.

Same for the .c change.

thanks,

greg k-h