On 10/02/2013 03:29 AM, Alexander Gordeev wrote:

As result, device drivers will cease to use the overcomplicated
repeated fallbacks technique and resort to a straightforward
pattern - determine the number of MSI/MSI-X interrupts required
before calling pci_enable_msi_block() and pci_enable_msix()
interfaces:


	rc = pci_msix_table_size(adapter->pdev);
	if (rc < 0)
		return rc;

	nvec = min(nvec, rc);
	if (nvec < FOO_DRIVER_MINIMUM_NVEC) {
		return -ENOSPC;

	for (i = 0; i < nvec; i++)
		adapter->msix_entries[i].entry = i;

	rc = pci_enable_msix(adapter->pdev,
			     adapter->msix_entries, nvec);
	return rc;

Why not add a minimum number to pci_enable_msix(), i.e.:

pci_enable_msix(pdev, msix_entries, nvec, minvec)

... which means "nvec" is the number of interrupts *requested*, and
"minvec" is the minimum acceptable number (otherwise fail).

	-hpa