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Subject[PATCH 3.12 085/104] igb: fix driver reload with VF assigned to guest
Date
From: Stefan Assmann <sassmann@kpanic.de>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 781798a11e2820ee35fa9142869bb8cec117dedc upstream.

commit fa44f2f185f7f9da19d331929bb1b56c1ccd1d93 broke reloading of igb, when
VFs are assigned to a guest, in several ways.
1. on module load adapter->vf_data does not get properly allocated,
resulting in a null pointer exception when accessing adapter->vf_data in
igb_reset() on module reload.
modprobe -r igb ; modprobe igb max_vfs=7
[ 215.215837] igb 0000:01:00.1: removed PHC on eth1
[ 216.932072] igb 0000:01:00.1: IOV Disabled
[ 216.937038] igb 0000:01:00.0: removed PHC on eth0
[ 217.127032] igb 0000:01:00.0: Cannot deallocate SR-IOV virtual functions while they are assigned - VFs will not be deallocated
[ 217.146178] igb: Intel(R) Gigabit Ethernet Network Driver - version 5.0.5-k
[ 217.154050] igb: Copyright (c) 2007-2013 Intel Corporation.
[ 217.160688] igb 0000:01:00.0: Enabling SR-IOV VFs using the module parameter is deprecated - please use the pci sysfs interface.
[ 217.173703] igb 0000:01:00.0: irq 103 for MSI/MSI-X
[ 217.179227] igb 0000:01:00.0: irq 104 for MSI/MSI-X
[ 217.184735] igb 0000:01:00.0: irq 105 for MSI/MSI-X
[ 217.220082] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048
[ 217.228846] IP: [<ffffffffa007c5e5>] igb_reset+0xc5/0x4b0 [igb]
[ 217.235472] PGD 3607ec067 PUD 36170b067 PMD 0
[ 217.240461] Oops: 0002 [#1] SMP
[ 217.244085] Modules linked in: igb(+) igbvf mptsas mptscsih mptbase scsi_transport_sas [last unloaded: igb]
[ 217.255040] CPU: 4 PID: 4833 Comm: modprobe Not tainted 3.11.0+ #46
[...]
[ 217.390007] [<ffffffffa007fab2>] igb_probe+0x892/0xfd0 [igb]
[ 217.396422] [<ffffffff81470b3e>] local_pci_probe+0x1e/0x40
[ 217.402641] [<ffffffff81472029>] pci_device_probe+0xf9/0x110
[...]
2. A follow up issue, pci_enable_sriov() should only be called if no VFs were
still allocated on module unload. Otherwise pci_enable_sriov() gets called
multiple times in a row rendering the NIC unusable until reset.
3. simply calling igb_enable_sriov() in igb_probe_vfs() is not enough as the
interrupts need to be re-setup. Switching that to igb_pci_enable_sriov().

Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Tested-by: Sibai Li <Sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/net/ethernet/intel/igb/igb_main.c | 37 +++++++++++++------------------
1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 318017d7dada..2b76ae55f2af 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -182,6 +182,7 @@ static void igb_check_vf_rate_limit(struct igb_adapter *);

#ifdef CONFIG_PCI_IOV
static int igb_vf_configure(struct igb_adapter *adapter, int vf);
+static int igb_pci_enable_sriov(struct pci_dev *dev, int num_vfs);
#endif

#ifdef CONFIG_PM
@@ -2423,7 +2424,7 @@ err_dma:
}

#ifdef CONFIG_PCI_IOV
-static int igb_disable_sriov(struct pci_dev *pdev)
+static int igb_disable_sriov(struct pci_dev *pdev)
{
struct net_device *netdev = pci_get_drvdata(pdev);
struct igb_adapter *adapter = netdev_priv(netdev);
@@ -2464,27 +2465,19 @@ static int igb_enable_sriov(struct pci_dev *pdev, int num_vfs)
int err = 0;
int i;

- if (!adapter->msix_entries) {
+ if (!adapter->msix_entries || num_vfs > 7) {
err = -EPERM;
goto out;
}
-
if (!num_vfs)
goto out;
- else if (old_vfs && old_vfs == num_vfs)
- goto out;
- else if (old_vfs && old_vfs != num_vfs)
- err = igb_disable_sriov(pdev);
-
- if (err)
- goto out;

- if (num_vfs > 7) {
- err = -EPERM;
- goto out;
- }
-
- adapter->vfs_allocated_count = num_vfs;
+ if (old_vfs) {
+ dev_info(&pdev->dev, "%d pre-allocated VFs found - override max_vfs setting of %d\n",
+ old_vfs, max_vfs);
+ adapter->vfs_allocated_count = old_vfs;
+ } else
+ adapter->vfs_allocated_count = num_vfs;

adapter->vf_data = kcalloc(adapter->vfs_allocated_count,
sizeof(struct vf_data_storage), GFP_KERNEL);
@@ -2498,10 +2491,12 @@ static int igb_enable_sriov(struct pci_dev *pdev, int num_vfs)
goto out;
}

- err = pci_enable_sriov(pdev, adapter->vfs_allocated_count);
- if (err)
- goto err_out;
-
+ /* only call pci_enable_sriov() if no VFs are allocated already */
+ if (!old_vfs) {
+ err = pci_enable_sriov(pdev, adapter->vfs_allocated_count);
+ if (err)
+ goto err_out;
+ }
dev_info(&pdev->dev, "%d VFs allocated\n",
adapter->vfs_allocated_count);
for (i = 0; i < adapter->vfs_allocated_count; i++)
@@ -2617,7 +2612,7 @@ static void igb_probe_vfs(struct igb_adapter *adapter)
return;

pci_sriov_set_totalvfs(pdev, 7);
- igb_enable_sriov(pdev, max_vfs);
+ igb_pci_enable_sriov(pdev, max_vfs);

#endif /* CONFIG_PCI_IOV */
}
--
2.0.4


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