Re: [PATCH v4 0/7] PCI: endpoint/NTB: Harden vNTB resource management

[Koichiro Den]

On Wed, Feb 18, 2026 at 09:52:08PM +0530, Manivannan Sadhasivam wrote:
> On Wed, Feb 18, 2026 at 09:45:22PM +0530, Manivannan Sadhasivam wrote:
> > On Tue, Dec 02, 2025 at 04:23:41PM +0900, Koichiro Den wrote:
> > > The vNTB endpoint function (pci-epf-vntb) can be configured and reconfigured
> > > through configfs (link/unlink functions, start/stop the controller, update
> > > parameters). In practice, several pitfalls present: double-unmapping when two
> > > windows share a BAR, wrong parameter order in .drop_link leading to wrong
> > > object lookups, duplicate EPC teardown that leads to oopses, a work item
> > > running after resources were torn down, and inability to re-link/restart
> > > fundamentally because ntb_dev was embedded and the vPCI bus teardown was
> > > incomplete.
> > > 
> > > This series addresses those issues and hardens resource management across NTB
> > > EPF and PCI EP core:
> > > 
> > > - Avoid double iounmap when PEER_SPAD and CONFIG share the same BAR.
> > > - Fix configfs .drop_link parameter order so the correct groups are used during
> > >   unlink.
> > > - Remove duplicate EPC resource teardown in both pci-epf-vntb and pci-epf-ntb,
> > >   avoiding crashes on .allow_link failures and during .drop_link.
> > > - Stop the delayed cmd_handler work before clearing BARs/doorbells.
> > > - Manage ntb_dev as a devm-managed allocation and implement .remove() in the
> > >   vNTB PCI driver. Switch to pci_scan_root_bus().
> > > 
> > > With these changes, the controller can now be stopped, a function unlinked,
> > > configfs settings updated, and the controller re-linked and restarted
> > > without rebooting the endpoint, as long as the underlying pci_epc_ops
> > > .stop() is non-destructive and .start() restores normal operation.
> > > 
> > > Patches 1-5 carry Fixes tags and are candidates for stable.
> > > Patch 6 is a preparatory one for Patch 7.
> > > Patch 7 is a behavioral improvement that completes lifetime management for
> > > relink/restart scenarios.
> > > 
> > 
> > Are there any dependencies between pci-epf-vntb and ntb-epf drivers? If they are
> > not dependent, you should always post them separately.

I'll make sure to be more careful.

> > For this series, I can
> > merge the endpoint patches (except patch 4 which got merged in other form).
> > 
> 
> Sry, patch 2.

There are no dependencies between Patch 1 and Patch 3-7.

One minor note: I just realized that the Patch 5 subject is inconsistent.

  NTB: epf: vntb: Stop cmd_handler work in epf_ntb_epc_cleanup

should have been

  PCI: endpoint: pci-epf-vntb: Stop cmd_handler work in epf_ntb_epc_cleanup

If possible, could you please adjust the subject when applying?

Best regards,
Koichiro

> 
> - Mani
> 
> > - Mani
> > 
> > > 
> > > v3->v4 changes:
> > >   - Added Reviewed-by tag for [PATCH v3 6/6].
> > >   - Corrected patch split by moving the blank-line cleanup,
> > >     based on the feedback from Frank.
> > >   (No code changes overall.)
> > > v2->v3 changes:
> > >   - Added Reviewed-by tag for [PATCH v2 4/6].
> > >   - Split [PATCH v2 6/6] into two, based on the feedback from Frank.
> > >   (No code changes overall.)
> > > v1->v2 changes:
> > >   - Incorporated feedback from Frank.
> > >   - Added Reviewed-by tags (except for patches #4 and #6).
> > >   - Fixed a typo in patch #5 title.
> > >   (No code changes overall.)
> > > 
> > > v3: https://lore.kernel.org/all/20251130151100.2591822-1-den@xxxxxxxxxxxxx/
> > > v2: https://lore.kernel.org/all/20251029080321.807943-1-den@xxxxxxxxxxxxx/
> > > v1: https://lore.kernel.org/all/20251023071757.901181-1-den@xxxxxxxxxxxxx/
> > > 
> > > 
> > > Koichiro Den (7):
> > >   NTB: epf: Avoid pci_iounmap() with offset when PEER_SPAD and CONFIG
> > >     share BAR
> > >   PCI: endpoint: Fix parameter order for .drop_link
> > >   PCI: endpoint: pci-epf-vntb: Remove duplicate resource teardown
> > >   PCI: endpoint: pci-epf-ntb: Remove duplicate resource teardown
> > >   NTB: epf: vntb: Stop cmd_handler work in epf_ntb_epc_cleanup
> > >   PCI: endpoint: pci-epf-vntb: Switch vpci_scan_bus() to use
> > >     pci_scan_root_bus()
> > >   PCI: endpoint: pci-epf-vntb: manage ntb_dev lifetime and fix vpci bus
> > >     teardown
> > > 
> > >  drivers/ntb/hw/epf/ntb_hw_epf.c               |  3 +-
> > >  drivers/pci/endpoint/functions/pci-epf-ntb.c  | 56 +-----------
> > >  drivers/pci/endpoint/functions/pci-epf-vntb.c | 86 ++++++++++++-------
> > >  drivers/pci/endpoint/pci-ep-cfs.c             |  8 +-
> > >  4 files changed, 62 insertions(+), 91 deletions(-)
> > > 
> > > -- 
> > > 2.48.1
> > > 
> > 
> > -- 
> > மணிவண்ணன் சதாசிவம்
> > 
> 
> -- 
> மணிவண்ணன் சதாசிவம்