From: Ferruh Yigit <ferruh.yigit@intel.com>
Date: Tue, 5 Jul 2016 15:00:52 +0000 (+0100)
Subject: igb_uio: fix possible mmap failure with Linux 4.5
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=d05aafe62f20addf29cd458642496806b97ffc83;p=dpdk.git

igb_uio: fix possible mmap failure with Linux 4.5

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>
---

diff --git a/doc/guides/rel_notes/release_16_07.rst b/doc/guides/rel_notes/release_16_07.rst
index 569f562fd8..e2af147439 100644
--- a/doc/guides/rel_notes/release_16_07.rst
+++ b/doc/guides/rel_notes/release_16_07.rst
@@ -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
 ~~~~~~~
diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
index 45a5720e2d..df41e457ad 100644
--- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
+++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
@@ -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);