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igb_uio: fix possible mmap failure with Linux 4.5

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mmap the iomem range of the PCI device fails for kernels that
enabled CONFIG_IO_STRICT_DEVMEM option:

EAL: pci_map_resource():
         cannot mmap(39, 0x7f1c51800000, 0x100000, 0x0):
         Invalid argument (0xffffffffffffffff)

CONFIG_IO_STRICT_DEVMEM is introduced in Linux v4.5 and not enabled
by default:
Linux commit: 90a545e restrict /dev/mem to idle io memory ranges

As a workaround igb_uio can stop reserving PCI memory resources, from
kernel point of view iomem region looks like idle and mmap works
again. This matches uio_pci_generic usage.

With this update device iomem range is not protected against any
other kernel drivers or userspace access. But this  shouldn't
be a problem for dpdk usage module since purpose of the igb_uio
module is to provide userspace access.

Fixes: af75078fece3 ("first public release")

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
This commit is contained in:
Ferruh Yigit 2016-07-05 16:00:52 +01:00 committed by Thomas Monjalon
parent b78c917511
commit d05aafe62f
2 changed files with 15 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
doc/guides/rel_notes/release_16_07.rst
View File

@ -195,6 +195,21 @@ Resolved Issues
EAL
~~~
* **igb_uio: Fixed possible mmap failure for Linux >= 4.5.**
mmaping the iomem range of the PCI device fails for kernels that
enabled CONFIG_IO_STRICT_DEVMEM option:
EAL: pci_map_resource():
cannot mmap(39, 0x7f1c51800000, 0x100000, 0x0):
Invalid argument (0xffffffffffffffff)
CONFIG_IO_STRICT_DEVMEM is introduced in Linux v4.5
Updated igb_uio to stop reserving PCI memory resources, from
kernel point of view iomem region looks like idle and mmap worked
again. This matches uio_pci_generic usage.
Drivers
~~~~~~~

13
lib/librte_eal/linuxapp/igb_uio/igb_uio.c
View File

@ -342,16 +342,6 @@ igbuio_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
goto fail_free;
}
/*
* reserve device's PCI memory regions for use by this
* module
*/
err = pci_request_regions(dev, "igb_uio");
if (err != 0) {
dev_err(&dev->dev, "Cannot request regions\n");
goto fail_disable;
}
/* enable bus mastering on the device */
pci_set_master(dev);
@ -441,8 +431,6 @@ fail_release_iomem:
igbuio_pci_release_iomem(&udev->info);
if (udev->mode == RTE_INTR_MODE_MSIX)
pci_disable_msix(udev->pdev);
pci_release_regions(dev);
fail_disable:
pci_disable_device(dev);
fail_free:
kfree(udev);
@ -460,7 +448,6 @@ igbuio_pci_remove(struct pci_dev *dev)
igbuio_pci_release_iomem(&udev->info);
if (udev->mode == RTE_INTR_MODE_MSIX)
pci_disable_msix(dev);
pci_release_regions(dev);
pci_disable_device(dev);
pci_set_drvdata(dev, NULL);
kfree(udev);