On Fri, 2009-05-15 at 13:59 +0900, Hidetoshi Seto wrote:
> In current code it continues setup even if alloc_msi_entry for MSI-X
> is failed due to lack of memory. It means arch_setup_msi_irqs() might
> be called with msi_desc entries less than its argument nvec.
>
> At least x86's arch_setup_msi_irqs() uses list_for_each_entry() for
> dev->msi_list that suspected to have entries same numbers as nvec, and
> it doesn't check the number of allocated vectors and passed arg nvec.
> Therefore it will result in success of pci_enable_msix(), with less
> vectors allocated than requested.
>
> This patch fixes the error route to return the number of entries can be
> allocated, instead of continuing the setup. It will let drivers to
> retry pci_enable_msix() with less number of entries.
>
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
> ---
> drivers/pci/msi.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 6f2e629..952432a 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -445,8 +445,10 @@ static int msix_capability_init(struct pci_dev *dev,
> /* MSI-X Table Initialization */
> for (i = 0; i < nvec; i++) {
> entry = alloc_msi_entry(dev);
> - if (!entry)
> - break;
> + if (!entry) {
> + msi_free_irqs(dev);
> + return i;
> + }
>
> j = entries[i].entry;
> entry->msi_attrib.is_msix = 1;
That looks right to me. Have you tested it? By faking allocation failure
in alloc_msi_entry().
As requested:
Acked-by: Michael Ellerman <michael@xxxxxxxxxxxxxx>
I guess this would be a nice fix for 30, but no one's hit it yet so it's
not urgent and could wait for 31.
cheers
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