On Thu, Jun 19, 2014 at 04:30:48PM +0800, Yijing Wang wrote:
> Move MSI entry stuff to a new function
> msi_setup_entry(), simplify msi_capability_init()
> code like MSI-X do.
I like this in general, but ...
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> ---
> drivers/pci/msi.c | 71 +++++++++++++++++++++++++++++++---------------------
> 1 files changed, 42 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index d8e431d..8e17446 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -582,6 +582,35 @@ error_attrs:
> return ret;
> }
>
> +static int msi_setup_entry(struct pci_dev *dev)
> +{
> + u16 control;
> + struct msi_desc *entry;
> +
> + entry = alloc_msi_entry(dev);
> + if (!entry)
> + return -ENOMEM;
> +
> + pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
> +
> + entry->msi_attrib.is_msix = 0;
> + entry->msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
> + entry->msi_attrib.entry_nr = 0;
> + entry->msi_attrib.maskbit = !!(control & PCI_MSI_FLAGS_MASKBIT);
> + entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
> + entry->msi_attrib.pos = dev->msi_cap;
> + entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
> +
> + if (control & PCI_MSI_FLAGS_64BIT)
> + entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
> + else
> + entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
> +
> +
> + list_add_tail(&entry->list, &dev->msi_list);
> + return 0;
Why don't you just return "entry" here (and NULL for the failure above)?
> +}
> +
> /**
> * msi_capability_init - configure device's MSI capability structure
> * @dev: pointer to the pci_dev data structure of MSI device function
> @@ -597,51 +626,30 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
> {
> struct msi_desc *entry;
> int ret;
> - u16 control;
> unsigned mask;
>
> msi_set_enable(dev, 0); /* Disable MSI during set up */
>
> - pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
> /* MSI Entry Initialization */
> - entry = alloc_msi_entry(dev);
> - if (!entry)
> - return -ENOMEM;
> -
> - entry->msi_attrib.is_msix = 0;
> - entry->msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
> - entry->msi_attrib.entry_nr = 0;
> - entry->msi_attrib.maskbit = !!(control & PCI_MSI_FLAGS_MASKBIT);
> - entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
> - entry->msi_attrib.pos = dev->msi_cap;
> - entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
> + ret = msi_setup_entry(dev);
> + if (ret)
> + return ret;
>
> - if (control & PCI_MSI_FLAGS_64BIT)
> - entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
> - else
> - entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
> + entry = list_first_entry(&dev->msi_list, struct msi_desc, list);
> /* All MSIs are unmasked by default, Mask them all */
> if (entry->msi_attrib.maskbit)
> pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
> mask = msi_mask(entry->msi_attrib.multi_cap);
> msi_mask_irq(entry, mask, mask);
>
> - list_add_tail(&entry->list, &dev->msi_list);
And keep the list_add_tail() here. Then you don't have the awkwardness of
pulling the entry off the list after calling msi_setup_entry().
That also means the MSIs can be masked before putting the entry on
dev->msi_list, as they were before. It *might* be safe to change the order
as you did, but it definitely takes some analysis to prove it, especially
since pci_enable_msi_range() only WARNs but doesn't bail out if
dev->msi_enabled already.
> /* Configure MSI capability structure */
> ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
> - if (ret) {
> - msi_mask_irq(entry, mask, ~mask);
> - free_msi_irqs(dev);
> - return ret;
> - }
> + if (ret)
> + goto err;
>
> ret = populate_msi_sysfs(dev);
> - if (ret) {
> - msi_mask_irq(entry, mask, ~mask);
> - free_msi_irqs(dev);
> - return ret;
> - }
> + if (ret)
> + goto err;
>
> /* Set MSI enabled bits */
> pci_intx_for_msi(dev, 0);
> @@ -650,6 +658,11 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
>
> dev->irq = entry->irq;
> return 0;
> +
> +err:
> + msi_mask_irq(entry, mask, ~mask);
> + free_msi_irqs(dev);
> + return ret;
> }
>
> static void __iomem *msix_map_region(struct pci_dev *dev, unsigned nr_entries)
> --
> 1.7.1
>
>
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