From b5fbf53324f65646154e172af350674d5a2a1629 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 11 Feb 2009 22:27:02 +1100 Subject: [PATCH] PCI/MSI: Allow arch code to return the number of MSI-X available There is code in msix_capability_init() which, when the requested number of MSI-X couldn't be allocated, calculates how many MSI-X /could/ be allocated and returns that to the driver. That allows the driver to then make a second request, with a number of MSIs that should succeed. The current code requires the arch code to setup as many msi_descs as it can, and then return to the generic code. On some platforms the arch code may already know how many MSI-X it can allocate, before it sets up any of the msi_descs. So change the logic such that if the arch code returns a positive error code, that is taken to be the number of MSI-X that could be allocated. If the error code is negative we still calculate the number available using the old method. Because it's a little subtle, make sure the error return code from arch_setup_msi_irq() is always negative. That way only implementations of arch_setup_msi_irqs() need to be careful about returning a positive error code. Signed-off-by: Michael Ellerman Signed-off-by: Jesse Barnes --- drivers/pci/msi.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 33adf323f06..dceea56f734 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -42,8 +42,10 @@ int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) list_for_each_entry(entry, &dev->msi_list, list) { ret = arch_setup_msi_irq(dev, entry); - if (ret) + if (ret < 0) return ret; + if (ret > 0) + return -ENOSPC; } return 0; @@ -487,7 +489,9 @@ static int msix_capability_init(struct pci_dev *dev, } ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); - if (ret) { + if (ret < 0) { + /* If we had some success report the number of irqs + * we succeeded in setting up. */ int avail = 0; list_for_each_entry(entry, &dev->msi_list, list) { if (entry->irq != 0) { @@ -495,14 +499,13 @@ static int msix_capability_init(struct pci_dev *dev, } } - msi_free_irqs(dev); + if (avail != 0) + ret = avail; + } - /* If we had some success report the number of irqs - * we succeeded in setting up. - */ - if (avail == 0) - avail = ret; - return avail; + if (ret) { + msi_free_irqs(dev); + return ret; } i = 0; -- 2.41.1