Messages in this thread | | | Date | Sat, 11 Oct 2003 01:11:37 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] x86_84 pci_map_sg fix for 2.6.0-test7 |
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On Fri, Oct 10, 2003 at 02:26:33PM -0700, Badari Pulavarty wrote: > Hi, > > Here is the patch to fix few minor issues with pci_map_sg() and pci_map_cont() > for x86_64. I ran into these asserts while testing with qlogic fc driver.
Sounds like the driver is buggy.
> > The patch fixes following: > > 1) pci_map_sg() coalsces "sg" entries without modifying command's > "use_sg" value. It sets the "sg" entries length to "0" to indicate that > these entires are coalsced. If the command gets retried, the pci_map_sg() > code trips on the assert that all entries length should be > 0.
As I explained for your last patch this change is wrong. Remapping an already mapped sg is not possible - it leaks IOMMU space and cause eventually system failure when the aperture fills up.
You have to somehow handle this in the caller, the pci-dma layer cannot do it. Eeither free the modified sg and retry with the original one or better just don't remap it and use the already mapped one)
I will add an BUG for passing sgs with dma_address != NULL to pci_map_sg(). This should catch such abuses early.
> > 2) __pci_map_cont() incorrectly assumes that "start" is always 0, so it > trips on few asserts.
That's the same high level bug I think.
-Andi
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