Re: [patch 14/32] s390/pci: Rework MSI descriptor walk

[Niklas Schnelle]

On Sat, 2021-11-27 at 02:23 +0100, Thomas Gleixner wrote:
> Replace the about to vanish iterators and make use of the filtering.
> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
>  arch/s390/pci/pci_irq.c |    6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> --- a/arch/s390/pci/pci_irq.c
> +++ b/arch/s390/pci/pci_irq.c
> @@ -303,7 +303,7 @@ int arch_setup_msi_irqs(struct pci_dev *
>  
>  	/* Request MSI interrupts */
>  	hwirq = bit;
> -	for_each_pci_msi_entry(msi, pdev) {
> +	msi_for_each_desc(msi, &pdev->dev, MSI_DESC_NOTASSOCIATED) {
>  		rc = -EIO;
>  		if (hwirq - bit >= msi_vecs)
>  			break;
> @@ -362,9 +362,7 @@ void arch_teardown_msi_irqs(struct pci_d
>  		return;
>  
>  	/* Release MSI interrupts */
> -	for_each_pci_msi_entry(msi, pdev) {
> -		if (!msi->irq)
> -			continue;
> +	msi_for_each_desc(msi, &pdev->dev, MSI_DESC_ASSOCIATED) {
>  		irq_set_msi_desc(msi->irq, NULL);
>  		irq_free_desc(msi->irq);
>  		msi->msg.address_lo = 0;
> 

Hi Thomas,

while the change looks good to me I ran into some trouble trying to
test it. I tried with the git repository you linked in the cover
letter:
git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-3

But with that I get the following linker error on s390:

s390x-11.2.0-ld: drivers/pci/msi/legacy.o: in function `pci_msi_legacy_setup_msi_irqs':
/home/nschnelle/mainline/drivers/pci/msi/legacy.c:72: undefined reference to `msi_device_populate_sysfs'
s390x-11.2.0-ld: drivers/pci/msi/legacy.o: in function `pci_msi_legacy_teardown_msi_irqs':
/home/nschnelle/mainline/drivers/pci/msi/legacy.c:78: undefined reference to `msi_device_destroy_sysfs'
make: *** [Makefile:1161: vmlinux] Error 1

This is caused by a misspelling of CONFIG_PCI_MSI_ARCH_FALLBACKS
(missing the final S) in kernel/irq/msi.c. With that fixed everything
builds and MSI IRQs work fine. So with that fixed you have my

Acked-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
Tested-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>

Best regards,
Niklas