Matthew Wilcox wrote:
> On Tue, Jun 23, 2009 at 05:39:00PM +0900, Hidetoshi Seto wrote:
>> 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.
That would make sense. Then how about this version?
Thanks,
H.Seto
===
[PATCH] pci, msi: Return if alloc_msi_entry() for MSI-X failed v2
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 -ENOMEM, instead of continuing
the setup.
Note that there is no iounmap in msi_free_irqs() if no msi_disc is
allocated.
v2: Return -ENOMEM always if failed, instead of returning the number of
entries can be allocated. (proposed by Matthew Milcox)
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 d069b5e..36917fd 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -451,8 +451,14 @@ 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);
+ else
+ msi_free_irqs(dev);
+ /* No enough memory. Don't try again */
+ return -ENOMEM;
+ }
j = entries[i].entry;
entry->msi_attrib.is_msix = 1;
--
1.6.3.3
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