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s390/pci: improve unreg_ioat error handling
DMA tables are freed in zpci_dma_exit_device regardless of the return code of zpci_unregister_ioat. This could lead to a use after free. On the other hand during function hot-unplug, zpci_unregister_ioat will always fail since the function is already gone. So let zpci_unregister_ioat report success when the function is gone but don't cleanup the dma table when a function could still have it in access. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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parent
4dfbd3efe3
commit
7257083491
2 changed files with 17 additions and 6 deletions
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@ -161,19 +161,28 @@ static int mod_pci(struct zpci_dev *zdev, int fn, u8 dmaas, struct mod_pci_args
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int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
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u64 base, u64 limit, u64 iota)
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{
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struct mod_pci_args args = { base, limit, iota, 0 };
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u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_REG_IOAT);
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struct zpci_fib fib = {0};
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u8 status;
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WARN_ON_ONCE(iota & 0x3fff);
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args.iota |= ZPCI_IOTA_RTTO_FLAG;
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return mod_pci(zdev, ZPCI_MOD_FC_REG_IOAT, dmaas, &args);
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fib.pba = base;
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fib.pal = limit;
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fib.iota = iota | ZPCI_IOTA_RTTO_FLAG;
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return zpci_mod_fc(req, &fib, &status) ? -EIO : 0;
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}
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/* Modify PCI: Unregister I/O address translation parameters */
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int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
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{
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struct mod_pci_args args = { 0, 0, 0, 0 };
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u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_DEREG_IOAT);
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struct zpci_fib fib = {0};
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u8 cc, status;
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return mod_pci(zdev, ZPCI_MOD_FC_DEREG_IOAT, dmaas, &args);
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cc = zpci_mod_fc(req, &fib, &status);
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if (cc == 3) /* Function already gone. */
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cc = 0;
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return cc ? -EIO : 0;
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}
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/* Modify PCI: Set PCI function measurement parameters */
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@ -601,7 +601,9 @@ void zpci_dma_exit_device(struct zpci_dev *zdev)
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*/
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WARN_ON(zdev->s390_domain);
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zpci_unregister_ioat(zdev, 0);
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if (zpci_unregister_ioat(zdev, 0))
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return;
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dma_cleanup_tables(zdev->dma_table);
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zdev->dma_table = NULL;
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vfree(zdev->iommu_bitmap);
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