On Tue, Jun 23, 2009 at 05:39:00PM +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.
Yeah. To be honest, this is silly. 32-byte GFP_KERNEL allocations
basically don't fail.
> This patch fixes the error route to return the number of entries can be
> allocated (or -ENOMEM), instead of continuing the setup. It will let
> drivers to retry pci_enable_msix() with less number of entries.
If we're running out of memory while doing pci_enable_msix(), should we
even be trying again? Something else is bound to run out of memory later
(creating irqs consumes an awful lot of memory). Might as well return
-ENOMEM and have done with it.
> Note that there is no iounmap in msi_free_irqs() if no msi_disc is
> allocated.
Yes, that's unfortunate.
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
> ---
> drivers/pci/msi.c | 10 ++++++++--
> 1 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index e176316..e784526 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -463,8 +463,14 @@ static int msix_capability_init(struct pci_dev *dev,
>
> for (i = 0; i < nvec; i++) {
> entry = alloc_msi_entry(dev);
> - if (!entry)
> - break;
> + if (!entry) {
> + if (!i) {
> + iounmap(base);
> + return -ENOMEM;
> + }
> + msi_free_irqs(dev);
> + return i;
> + }
>
> j = entries[i].entry;
> entry->msi_attrib.is_msix = 1;
> --
> 1.6.3.3
>
>
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--
Matthew Wilcox Intel Open Source Technology Centre
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operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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