[PATCH v2 0/2] vfio: export and make use of pci_dev_trylock()

[PATCH v2 0/2] vfio: export and make use of pci_dev_trylock()

[Luis Chamberlain]

This v2 series addreses the changes requested by Bjorn, namely:

  - moved the new forward declarations next to pci_cfg_access_lock()
    as requested
  - modify the subject patch for the first PCI patch

Luis Chamberlain (2):
  PCI: Export pci_dev_trylock() and pci_dev_unlock()
  vfio: use the new pci_dev_trylock() helper to simplify try lock

 drivers/pci/pci.c           |  6 ++++--
 drivers/vfio/pci/vfio_pci.c | 11 ++++-------
 include/linux/pci.h         |  3 +++
 3 files changed, 11 insertions(+), 9 deletions(-)

-- 
2.30.2

[PATCH v2 1/2] PCI: Export pci_dev_trylock() and pci_dev_unlock()

[Luis Chamberlain]

Other places in the kernel use this form, and so just
provide a common path for it.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/pci/pci.c   | 6 ++++--
 include/linux/pci.h | 3 +++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f09821af1d2e..b1d9bb3f5ae2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5027,7 +5027,7 @@ static void pci_dev_lock(struct pci_dev *dev)
 }
 
 /* Return 1 on successful lock, 0 on contention */
-static int pci_dev_trylock(struct pci_dev *dev)
+int pci_dev_trylock(struct pci_dev *dev)
 {
 	if (pci_cfg_access_trylock(dev)) {
 		if (device_trylock(&dev->dev))
@@ -5037,12 +5037,14 @@ static int pci_dev_trylock(struct pci_dev *dev)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(pci_dev_trylock);
 
-static void pci_dev_unlock(struct pci_dev *dev)
+void pci_dev_unlock(struct pci_dev *dev)
 {
 	device_unlock(&dev->dev);
 	pci_cfg_access_unlock(dev);
 }
+EXPORT_SYMBOL_GPL(pci_dev_unlock);
 
 static void pci_dev_save_and_disable(struct pci_dev *dev)
 {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 6248e044dd29..d8f056f3a2e3 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1622,6 +1622,9 @@ void pci_cfg_access_lock(struct pci_dev *dev);
 bool pci_cfg_access_trylock(struct pci_dev *dev);
 void pci_cfg_access_unlock(struct pci_dev *dev);
 
+int pci_dev_trylock(struct pci_dev *dev);
+void pci_dev_unlock(struct pci_dev *dev);
+
 /*
  * PCI domain support.  Sometimes called PCI segment (eg by ACPI),
  * a PCI domain is defined to be a set of PCI buses which share
-- 
2.30.2

Re: [PATCH v2 1/2] PCI: Export pci_dev_trylock() and pci_dev_unlock()

[Cornelia Huck]

On Tue, Jun 22 2021, Luis Chamberlain <mcgrof@kernel.org> wrote:

> Other places in the kernel use this form, and so just
> provide a common path for it.
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  drivers/pci/pci.c   | 6 ++++--
>  include/linux/pci.h | 3 +++
>  2 files changed, 7 insertions(+), 2 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

[PATCH v2 2/2] vfio: use the new pci_dev_trylock() helper to simplify try lock

[Luis Chamberlain]

Use the new pci_dev_trylock() helper to simplify our locking.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/vfio/pci/vfio_pci.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index bd7c482c948a..02b05f7b9a91 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -477,13 +477,10 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
 	 * We can not use the "try" reset interface here, which will
 	 * overwrite the previously restored configuration information.
 	 */
-	if (vdev->reset_works && pci_cfg_access_trylock(pdev)) {
-		if (device_trylock(&pdev->dev)) {
-			if (!__pci_reset_function_locked(pdev))
-				vdev->needs_reset = false;
-			device_unlock(&pdev->dev);
-		}
-		pci_cfg_access_unlock(pdev);
+	if (vdev->reset_works && pci_dev_trylock(pdev)) {
+		if (!__pci_reset_function_locked(pdev))
+			vdev->needs_reset = false;
+		pci_dev_unlock(pdev);
 	}
 
 	pci_restore_state(pdev);
-- 
2.30.2

Re: [PATCH v2 2/2] vfio: use the new pci_dev_trylock() helper to simplify try lock

[Cornelia Huck]

On Tue, Jun 22 2021, Luis Chamberlain <mcgrof@kernel.org> wrote:

> Use the new pci_dev_trylock() helper to simplify our locking.
>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  drivers/vfio/pci/vfio_pci.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Re: [PATCH v2 2/2] vfio: use the new pci_dev_trylock() helper to simplify try lock

[Jason Gunthorpe]

On Tue, Jun 22, 2021 at 07:28:24PM -0700, Luis Chamberlain wrote:
> Use the new pci_dev_trylock() helper to simplify our locking.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  drivers/vfio/pci/vfio_pci.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

Re: [PATCH v2 0/2] vfio: export and make use of pci_dev_trylock()

[Alex Williamson]

On Tue, 22 Jun 2021 19:28:22 -0700
Luis Chamberlain <mcgrof@kernel.org> wrote:

> This v2 series addreses the changes requested by Bjorn, namely:
> 
>   - moved the new forward declarations next to pci_cfg_access_lock()
>     as requested
>   - modify the subject patch for the first PCI patch

Looks ok to me and I assume by Bjorn's Ack that he's expecting it to go
through my tree.  I'll give a bit of time to note otherwise if that's
not the case.  Thanks,

Alex

> Luis Chamberlain (2):
>   PCI: Export pci_dev_trylock() and pci_dev_unlock()
>   vfio: use the new pci_dev_trylock() helper to simplify try lock
> 
>  drivers/pci/pci.c           |  6 ++++--
>  drivers/vfio/pci/vfio_pci.c | 11 ++++-------
>  include/linux/pci.h         |  3 +++
>  3 files changed, 11 insertions(+), 9 deletions(-)
> 

Re: [PATCH v2 0/2] vfio: export and make use of pci_dev_trylock()

[Alex Williamson]

On Tue, 22 Jun 2021 19:28:22 -0700
Luis Chamberlain <mcgrof@kernel.org> wrote:

> This v2 series addreses the changes requested by Bjorn, namely:
> 
>   - moved the new forward declarations next to pci_cfg_access_lock()
>     as requested
>   - modify the subject patch for the first PCI patch
> 
> Luis Chamberlain (2):
>   PCI: Export pci_dev_trylock() and pci_dev_unlock()
>   vfio: use the new pci_dev_trylock() helper to simplify try lock
> 
>  drivers/pci/pci.c           |  6 ++++--
>  drivers/vfio/pci/vfio_pci.c | 11 ++++-------
>  include/linux/pci.h         |  3 +++
>  3 files changed, 11 insertions(+), 9 deletions(-)
> 

Applied to vfio next branch for v5.14 with Bjorn's Ack, thanks!

Alex

Re: [PATCH v2 0/2] vfio: export and make use of pci_dev_trylock()

[Alex Williamson]

On Fri, 25 Jun 2021 09:04:51 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:

> On Tue, 22 Jun 2021 19:28:22 -0700
> Luis Chamberlain <mcgrof@kernel.org> wrote:
> 
> > This v2 series addreses the changes requested by Bjorn, namely:
> > 
> >   - moved the new forward declarations next to pci_cfg_access_lock()
> >     as requested
> >   - modify the subject patch for the first PCI patch
> > 
> > Luis Chamberlain (2):
> >   PCI: Export pci_dev_trylock() and pci_dev_unlock()
> >   vfio: use the new pci_dev_trylock() helper to simplify try lock
> > 
> >  drivers/pci/pci.c           |  6 ++++--
> >  drivers/vfio/pci/vfio_pci.c | 11 ++++-------
> >  include/linux/pci.h         |  3 +++
> >  3 files changed, 11 insertions(+), 9 deletions(-)
> >   
> 
> Applied to vfio next branch for v5.14 with Bjorn's Ack, thanks!

(and Jason & Conny's R-b)