[PATCH net 1/3] nfp: don't hold PF lock while enabling SR-IOV
flat view
STALE3343d
REVIEWED: 1 (0M)
From: Jakub Kicinski <hidden>
Date: 2017-08-23 06:22:52
Subsystem:
netronome ethernet drivers, networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
1 review trailer.
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
6d48ceb27af1 ("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: 6d48ceb27af1 ("nfp: allocate a private workqueue for driver work")
Signed-off-by: Jakub Kicinski <redacted>
Reviewed-by: Simon Horman <redacted>
---
drivers/net/ethernet/netronome/nfp/nfp_main.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_main.c b/drivers/net/ethernet/netronome/nfp/nfp_main.c
index d67969d3e484..3f199db2002e 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_main.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_main.c@@ -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; }
--
2.11.0