[PATCH] PCI:MSI Return -ENOSPC when requested vectors is not enough
Dennis Chen
dennis.chen at arm.com
Thu Dec 1 22:04:41 PST 2016
On Thu, Dec 01, 2016 at 09:52:43AM +0100, Christoph Hellwig wrote:
> Hi Dennis,
>
> I've fixed ahci to treat all errors the same in the meantime, please
> try latest Linux tree. That being said I don't like the different
> error returns from __pci_enable_msi_range (and __pci_enable_msix_range),
> but they have been there for a while.
Ah, I've noticed that you have the fix recently which is somehow to weaken
the necessary of the change. But, that also being said that I don't like we insist
at least the inconsistent either just because something has been there *for a while*.
Both below comments from cpi_alloc_irq_vectors_affinity() and the logic itself
leads us to think that the correct return value is -NOSPC:
/**
*...
*Return the number of vectors allocated,
* (which might be smaller than @max_vecs) if successful, or a negative
* error code on error. If less than @min_vecs interrupt vectors are
* available for @dev the function will fail with -ENOSPC.
* ...
*/
People maybe argue that almost has no device drivers depending on the different
return value, then why we still need to do that?
Thanks,
Dennis
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