Re: [PATCH 1/1] powerpc: Drop superfluous pci_dev_is_added() calls
Bjorn Helgaas writes: > On Fri, Sep 10, 2021 at 04:19:40PM +0200, Niklas Schnelle wrote: >> On powerpc, pci_dev_is_added() is called as part of SR-IOV fixups >> that are done under pcibios_add_device() which in turn is only called in >> pci_device_add() whih is called when a PCI device is scanned. >> >> Now pci_dev_assign_added() is called in pci_bus_add_device() which is >> only called after scanning the device. Thus pci_dev_is_added() is always >> false and can be dropped. >> >> Signed-off-by: Niklas Schnelle > > Reviewed-by: Bjorn Helgaas > > This doesn't touch the PCI core, so maybe makes sense for you to take > it, Michael? But let me know if you think otherwise. Yeah I'm happy to take it, thanks. cheers
Re: [PATCH 1/1] powerpc: Drop superfluous pci_dev_is_added() calls
On Fri, Sep 10, 2021 at 04:19:40PM +0200, Niklas Schnelle wrote:
> On powerpc, pci_dev_is_added() is called as part of SR-IOV fixups
> that are done under pcibios_add_device() which in turn is only called in
> pci_device_add() whih is called when a PCI device is scanned.
>
> Now pci_dev_assign_added() is called in pci_bus_add_device() which is
> only called after scanning the device. Thus pci_dev_is_added() is always
> false and can be dropped.
>
> Signed-off-by: Niklas Schnelle
Reviewed-by: Bjorn Helgaas
This doesn't touch the PCI core, so maybe makes sense for you to take
it, Michael? But let me know if you think otherwise.
Thanks a lot for cleaning this up, Niklas.
> ---
> arch/powerpc/platforms/powernv/pci-sriov.c | 6 --
> arch/powerpc/platforms/pseries/setup.c | 3 +--
> 2 files changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-sriov.c
> b/arch/powerpc/platforms/powernv/pci-sriov.c
> index 28aac933a439..deddbb233fde 100644
> --- a/arch/powerpc/platforms/powernv/pci-sriov.c
> +++ b/arch/powerpc/platforms/powernv/pci-sriov.c
> @@ -9,9 +9,6 @@
>
> #include "pci.h"
>
> -/* for pci_dev_is_added() */
> -#include "../../../../drivers/pci/pci.h"
> -
> /*
> * The majority of the complexity in supporting SR-IOV on PowerNV comes from
> * the need to put the MMIO space for each VF into a separate PE. Internally
> @@ -228,9 +225,6 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
> pci_dev *pdev)
>
> void pnv_pci_ioda_fixup_iov(struct pci_dev *pdev)
> {
> - if (WARN_ON(pci_dev_is_added(pdev)))
> - return;
> -
> if (pdev->is_virtfn) {
> struct pnv_ioda_pe *pe = pnv_ioda_get_pe(pdev);
>
> diff --git a/arch/powerpc/platforms/pseries/setup.c
> b/arch/powerpc/platforms/pseries/setup.c
> index f79126f16258..2188054470c1 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -74,7 +74,6 @@
> #include
>
> #include "pseries.h"
> -#include "../../../../drivers/pci/pci.h"
>
> DEFINE_STATIC_KEY_FALSE(shared_processor);
> EXPORT_SYMBOL(shared_processor);
> @@ -750,7 +749,7 @@ static void pseries_pci_fixup_iov_resources(struct
> pci_dev *pdev)
> const int *indexes;
> struct device_node *dn = pci_device_to_OF_node(pdev);
>
> - if (!pdev->is_physfn || pci_dev_is_added(pdev))
> + if (!pdev->is_physfn)
> return;
> /*Firmware must support open sriov otherwise dont configure*/
> indexes = of_get_property(dn, "ibm,open-sriov-vf-bar-info", NULL);
> --
> 2.25.1
>
Re: [PATCH 1/1] powerpc: Drop superfluous pci_dev_is_added() calls
On Sat, Sep 11, 2021 at 9:09 PM Michael Ellerman wrote:
>
> Niklas Schnelle writes:
> > On powerpc, pci_dev_is_added() is called as part of SR-IOV fixups
> > that are done under pcibios_add_device() which in turn is only called in
> > pci_device_add() whih is called when a PCI device is scanned.
>
> Thanks for cleaning this up for us.
>
> > Now pci_dev_assign_added() is called in pci_bus_add_device() which is
> > only called after scanning the device. Thus pci_dev_is_added() is always
> > false and can be dropped.
>
> My only query is whether we can pin down when that changed.
>
> Oliver said:
>
> The use of pci_dev_is_added() in arch/powerpc was because in the past
> pci_bus_add_device() could be called before pci_device_add(). That was
> fixed a while ago so It should be safe to remove those calls now.
>
> I trawled back through the history a bit but I can't remember/find which
> commit changed that, Oliver can you remember?
Yeah, on closer inspection that never happened. The re-ordering I was
thinking of was when the boot-time BAR assignments were moved in
3f068aae7a95 so they'd always occur before pci_bus_add_device() was
called. I think I got that change mixed up with commit 30d87ef8b38d
("powerpc/pci: Fix pcibios_setup_device() ordering") which moved some
of what what pcibios_device_add() did into pcibios_bus_add_device() to
harmonise the hot and coldplug paths.
As far as I can tell the pci_dev_is_added() check has been pointless
since the code was added in 6e628c7d33d9 ("powerpc/powernv: Reserve
additional space for IOV BAR according to the number of total_pe").
Even back then pci_device_add() was called first in both the normal
and OF based PCI probing paths so there's no circumstance where that
code would see the added flag set.
That patch was part of the PowerNV SRIOV support series which went
through quite a few iterations. My best guess is that check might have
been needed in an earlier version and was just carried forward until
it got merged. I didn't dig too deeply into the history though.
Reviewed-by: Oliver O'Halloran
Re: [PATCH 1/1] powerpc: Drop superfluous pci_dev_is_added() calls
Niklas Schnelle writes:
> On powerpc, pci_dev_is_added() is called as part of SR-IOV fixups
> that are done under pcibios_add_device() which in turn is only called in
> pci_device_add() whih is called when a PCI device is scanned.
Thanks for cleaning this up for us.
> Now pci_dev_assign_added() is called in pci_bus_add_device() which is
> only called after scanning the device. Thus pci_dev_is_added() is always
> false and can be dropped.
My only query is whether we can pin down when that changed.
Oliver said:
The use of pci_dev_is_added() in arch/powerpc was because in the past
pci_bus_add_device() could be called before pci_device_add(). That was
fixed a while ago so It should be safe to remove those calls now.
I trawled back through the history a bit but I can't remember/find which
commit changed that, Oliver can you remember?
cheers
> diff --git a/arch/powerpc/platforms/powernv/pci-sriov.c
> b/arch/powerpc/platforms/powernv/pci-sriov.c
> index 28aac933a439..deddbb233fde 100644
> --- a/arch/powerpc/platforms/powernv/pci-sriov.c
> +++ b/arch/powerpc/platforms/powernv/pci-sriov.c
> @@ -9,9 +9,6 @@
>
> #include "pci.h"
>
> -/* for pci_dev_is_added() */
> -#include "../../../../drivers/pci/pci.h"
> -
> /*
> * The majority of the complexity in supporting SR-IOV on PowerNV comes from
> * the need to put the MMIO space for each VF into a separate PE. Internally
> @@ -228,9 +225,6 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
> pci_dev *pdev)
>
> void pnv_pci_ioda_fixup_iov(struct pci_dev *pdev)
> {
> - if (WARN_ON(pci_dev_is_added(pdev)))
> - return;
> -
> if (pdev->is_virtfn) {
> struct pnv_ioda_pe *pe = pnv_ioda_get_pe(pdev);
>
> diff --git a/arch/powerpc/platforms/pseries/setup.c
> b/arch/powerpc/platforms/pseries/setup.c
> index f79126f16258..2188054470c1 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -74,7 +74,6 @@
> #include
>
> #include "pseries.h"
> -#include "../../../../drivers/pci/pci.h"
>
> DEFINE_STATIC_KEY_FALSE(shared_processor);
> EXPORT_SYMBOL(shared_processor);
> @@ -750,7 +749,7 @@ static void pseries_pci_fixup_iov_resources(struct
> pci_dev *pdev)
> const int *indexes;
> struct device_node *dn = pci_device_to_OF_node(pdev);
>
> - if (!pdev->is_physfn || pci_dev_is_added(pdev))
> + if (!pdev->is_physfn)
> return;
> /*Firmware must support open sriov otherwise dont configure*/
> indexes = of_get_property(dn, "ibm,open-sriov-vf-bar-info", NULL);
> --
> 2.25.1
