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nfp: don't hold PF lock while enabling SR-IOV 

Enabling SR-IOV VFs will cause the PCI subsystem to schedule a
work and flush its workqueue.  Since the nfp driver schedules its
own work we can't enable VFs while holding driver load.  Commit
6d48ceb27a ("nfp: allocate a private workqueue for driver work")
tried to avoid this deadlock by creating a separate workqueue.
Unfortunately, due to the architecture of workqueue subsystem this
does not guarantee a separate thread of execution.  Luckily
we can simply take pci_enable_sriov() from under the driver lock.

Take pci_disable_sriov() from under the lock too for symmetry.

Fixes: 6d48ceb27a ("nfp: allocate a private workqueue for driver work")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2017-08-22 23:22:42 -07:00 committed by David S. Miller
parent 2f19f50e0f
commit d6e1ab9ea3
1 changed files with 7 additions and 9 deletions
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16
drivers/net/ethernet/netronome/nfp/nfp_main.c
View File

@ -98,21 +98,20 @@ static int nfp_pcie_sriov_enable(struct pci_dev *pdev, int num_vfs)
struct nfp_pf *pf = pci_get_drvdata(pdev);
int err;
mutex_lock(&pf->lock);
if (num_vfs > pf->limit_vfs) {
nfp_info(pf->cpp, "Firmware limits number of VFs to %u\n",
pf->limit_vfs);
err = -EINVAL;
goto err_unlock;
return -EINVAL;
}
err = pci_enable_sriov(pdev, num_vfs);
if (err) {
dev_warn(&pdev->dev, "Failed to enable PCI SR-IOV: %d\n", err);
goto err_unlock;
return err;
}
mutex_lock(&pf->lock);
err = nfp_app_sriov_enable(pf->app, num_vfs);
if (err) {
dev_warn(&pdev->dev,
@ -129,9 +128,8 @@ static int nfp_pcie_sriov_enable(struct pci_dev *pdev, int num_vfs)
return num_vfs;
err_sriov_disable:
pci_disable_sriov(pdev);
err_unlock:
mutex_unlock(&pf->lock);
pci_disable_sriov(pdev);
return err;
#endif
return 0;
@ -158,10 +156,10 @@ static int nfp_pcie_sriov_disable(struct pci_dev *pdev)
pf->num_vfs = 0;
mutex_unlock(&pf->lock);
pci_disable_sriov(pdev);
dev_dbg(&pdev->dev, "Removed VFs.\n");
mutex_unlock(&pf->lock);
#endif
return 0;
}