| Message ID | 20180215144000.60456-2-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Thu, Feb 15, 2018 at 3:39 PM, Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > When distributing extra buses between hotplug bridges we need to make > sure each bridge reserve at least one bus number, even if there is > currently nothing connected to it. For instance ACPI hotplug may bring > in additional devices to non-hotplug bridges later on. To make sure we > don't run out of bus numbers for non-hotplug bridges reserve one bus > number for them upfront before distributing buses for hotplug bridges. > > Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable bridges") > Reported-by: Mario Limonciello <mario.limonciello@dell.com> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > Cc: stable@vger.kernel.org Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/pci/probe.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index ef5377438a1e..6cefd47556e3 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -2561,7 +2561,10 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, > for_each_pci_bridge(dev, bus) { > cmax = max; > max = pci_scan_bridge_extend(bus, dev, max, 0, 0); > - used_buses += cmax - max; > + /* Reserve one bus for each bridge */ > + used_buses++; > + if (cmax - max > 1) > + used_buses += cmax - max - 1; > } > > /* Scan bridges that need to be reconfigured */ > @@ -2584,12 +2587,14 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, > * bridges if any. > */ > buses = available_buses / hotplug_bridges; > - buses = min(buses, available_buses - used_buses); > + buses = min(buses, available_buses - used_buses + 1); > } > > cmax = max; > max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1); > - used_buses += max - cmax; > + /* One bus is already accounted so don't add it again */ > + if (max - cmax > 1) > + used_buses += max - cmax - 1; > } > > /* > -- > 2.15.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Feb 15, 2018 at 05:39:55PM +0300, Mika Westerberg wrote: > When distributing extra buses between hotplug bridges we need to make > sure each bridge reserve at least one bus number, even if there is > currently nothing connected to it. For instance ACPI hotplug may bring > in additional devices to non-hotplug bridges later on. To make sure we > don't run out of bus numbers for non-hotplug bridges reserve one bus > number for them upfront before distributing buses for hotplug bridges. > > Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable bridges") > Reported-by: Mario Limonciello <mario.limonciello@dell.com> Is there a bugzilla or email URL we can include here? > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > Cc: stable@vger.kernel.org > --- > drivers/pci/probe.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index ef5377438a1e..6cefd47556e3 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -2561,7 +2561,10 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, > for_each_pci_bridge(dev, bus) { > cmax = max; > max = pci_scan_bridge_extend(bus, dev, max, 0, 0); > - used_buses += cmax - max; > + /* Reserve one bus for each bridge */ > + used_buses++; > + if (cmax - max > 1) > + used_buses += cmax - max - 1; > } > > /* Scan bridges that need to be reconfigured */ > @@ -2584,12 +2587,14 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, > * bridges if any. > */ > buses = available_buses / hotplug_bridges; > - buses = min(buses, available_buses - used_buses); > + buses = min(buses, available_buses - used_buses + 1); > } > > cmax = max; > max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1); > - used_buses += max - cmax; > + /* One bus is already accounted so don't add it again */ > + if (max - cmax > 1) > + used_buses += max - cmax - 1; > } > > /* > -- > 2.15.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Feb 23, 2018 at 12:52:18AM +0000, Mario.Limonciello@dell.com wrote: > On Feb 22, 2018 18:27, Bjorn Helgaas <helgaas@kernel.org> wrote: > > On Thu, Feb 15, 2018 at 05:39:55PM +0300, Mika Westerberg wrote: > > > When distributing extra buses between hotplug bridges we need to make > > > sure each bridge reserve at least one bus number, even if there is > > > currently nothing connected to it. For instance ACPI hotplug may bring > > > in additional devices to non-hotplug bridges later on. To make sure we > > > don't run out of bus numbers for non-hotplug bridges reserve one bus > > > number for them upfront before distributing buses for hotplug bridges. > > > > > > Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable bridges") > > > Reported-by: Mario Limonciello <mario.limonciello@dell.com> > > > > Is there a bugzilla or email URL we can include here? > > Sorry it was private communication that I believe Mika is referring to in Reported-By here. > > You can remove the tag if you think it's inappropriate for this commit. I like to give credit whenever possible, so I wouldn't necessarily remove the Reported-by. But it would be very useful to also have a URL to something with more details, e.g., what sort of failure the user would observe, dmesg logs, PCI topology, etc. This information can certainly be redacted to remove any proprietary things that can't be made public. Usually that isn't of interest to structural issues like this anyway. > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > > Cc: stable@vger.kernel.org > > > --- > > > drivers/pci/probe.c | 11 ++++++++--- > > > 1 file changed, 8 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > > > index ef5377438a1e..6cefd47556e3 100644 > > > --- a/drivers/pci/probe.c > > > +++ b/drivers/pci/probe.c > > > @@ -2561,7 +2561,10 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, > > > for_each_pci_bridge(dev, bus) { > > > cmax = max; > > > max = pci_scan_bridge_extend(bus, dev, max, 0, 0); > > > - used_buses += cmax - max; > > > + /* Reserve one bus for each bridge */ > > > + used_buses++; > > > + if (cmax - max > 1) > > > + used_buses += cmax - max - 1; > > > } > > > > > > /* Scan bridges that need to be reconfigured */ > > > @@ -2584,12 +2587,14 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, > > > * bridges if any. > > > */ > > > buses = available_buses / hotplug_bridges; > > > - buses = min(buses, available_buses - used_buses); > > > + buses = min(buses, available_buses - used_buses + 1); > > > } > > > > > > cmax = max; > > > max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1); > > > - used_buses += max - cmax; > > > + /* One bus is already accounted so don't add it again */ > > > + if (max - cmax > 1) > > > + used_buses += max - cmax - 1; > > > } > > > > > > /* > > > -- > > > 2.15.1 > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html >
> -----Original Message----- > From: Bjorn Helgaas [mailto:helgaas@kernel.org] > Sent: Friday, February 23, 2018 11:26 AM > To: Limonciello, Mario <Mario_Limonciello@Dell.com> > Cc: bhelgaas@google.com; rjw@rjwysocki.net; > andriy.shevchenko@linux.intel.com; lenb@kernel.org; michael.jamet@intel.com; > yehezkel.bernat@intel.com; linux-acpi@vger.kernel.org; linux- > pci@vger.kernel.org; mika.westerberg@linux.intel.com > Subject: Re: [PATCH v2 1/5] PCI: Make sure all bridges reserve at least one bus > number > > On Fri, Feb 23, 2018 at 12:52:18AM +0000, Mario.Limonciello@dell.com wrote: > > On Feb 22, 2018 18:27, Bjorn Helgaas <helgaas@kernel.org> wrote: > > > On Thu, Feb 15, 2018 at 05:39:55PM +0300, Mika Westerberg wrote: > > > > When distributing extra buses between hotplug bridges we need to make > > > > sure each bridge reserve at least one bus number, even if there is > > > > currently nothing connected to it. For instance ACPI hotplug may bring > > > > in additional devices to non-hotplug bridges later on. To make sure we > > > > don't run out of bus numbers for non-hotplug bridges reserve one bus > > > > number for them upfront before distributing buses for hotplug bridges. > > > > > > > > Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable > bridges") > > > > Reported-by: Mario Limonciello <mario.limonciello@dell.com> > > > > > > Is there a bugzilla or email URL we can include here? > > > > Sorry it was private communication that I believe Mika is referring to in Reported- > By here. > > > > You can remove the tag if you think it's inappropriate for this commit. > > I like to give credit whenever possible, so I wouldn't necessarily > remove the Reported-by. > > But it would be very useful to also have a URL to something with more > details, e.g., what sort of failure the user would observe, dmesg > logs, PCI topology, etc. > > This information can certainly be redacted to remove any proprietary > things that can't be made public. Usually that isn't of interest to > structural issues like this anyway. It was a result of a very long communication chain, but I think I pulled out the relevant details here if you would like a URL to include: https://gist.github.com/superm1/100a2ed20449f684ebb84c392e35dbed Thank you. > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > > > Cc: stable@vger.kernel.org > > > > --- > > > > drivers/pci/probe.c | 11 ++++++++--- > > > > 1 file changed, 8 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > > > > index ef5377438a1e..6cefd47556e3 100644 > > > > --- a/drivers/pci/probe.c > > > > +++ b/drivers/pci/probe.c > > > > @@ -2561,7 +2561,10 @@ static unsigned int > pci_scan_child_bus_extend(struct pci_bus *bus, > > > > for_each_pci_bridge(dev, bus) { > > > > cmax = max; > > > > max = pci_scan_bridge_extend(bus, dev, max, 0, 0); > > > > - used_buses += cmax - max; > > > > + /* Reserve one bus for each bridge */ > > > > + used_buses++; > > > > + if (cmax - max > 1) > > > > + used_buses += cmax - max - 1; > > > > } > > > > > > > > /* Scan bridges that need to be reconfigured */ > > > > @@ -2584,12 +2587,14 @@ static unsigned int > pci_scan_child_bus_extend(struct pci_bus *bus, > > > > * bridges if any. > > > > */ > > > > buses = available_buses / hotplug_bridges; > > > > - buses = min(buses, available_buses - used_buses); > > > > + buses = min(buses, available_buses - used_buses + 1); > > > > } > > > > > > > > cmax = max; > > > > max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1); > > > > - used_buses += max - cmax; > > > > + /* One bus is already accounted so don't add it again */ > > > > + if (max - cmax > 1) > > > > + used_buses += max - cmax - 1; > > > > } > > > > > > > > /* > > > > -- > > > > 2.15.1 > > > > > > > > -- > > > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > > > the body of a message to majordomo@vger.kernel.org > > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > >
On Fri, Feb 23, 2018 at 07:06:59PM +0000, Mario.Limonciello@dell.com wrote: > > -----Original Message----- > > From: Bjorn Helgaas [mailto:helgaas@kernel.org] > > Sent: Friday, February 23, 2018 11:26 AM > > To: Limonciello, Mario <Mario_Limonciello@Dell.com> > > Cc: bhelgaas@google.com; rjw@rjwysocki.net; > > andriy.shevchenko@linux.intel.com; lenb@kernel.org; michael.jamet@intel.com; > > yehezkel.bernat@intel.com; linux-acpi@vger.kernel.org; linux- > > pci@vger.kernel.org; mika.westerberg@linux.intel.com > > Subject: Re: [PATCH v2 1/5] PCI: Make sure all bridges reserve at least one bus > > number > > > > On Fri, Feb 23, 2018 at 12:52:18AM +0000, Mario.Limonciello@dell.com wrote: > > > On Feb 22, 2018 18:27, Bjorn Helgaas <helgaas@kernel.org> wrote: > > > > On Thu, Feb 15, 2018 at 05:39:55PM +0300, Mika Westerberg wrote: > > > > > When distributing extra buses between hotplug bridges we need to make > > > > > sure each bridge reserve at least one bus number, even if there is > > > > > currently nothing connected to it. For instance ACPI hotplug may bring > > > > > in additional devices to non-hotplug bridges later on. To make sure we > > > > > don't run out of bus numbers for non-hotplug bridges reserve one bus > > > > > number for them upfront before distributing buses for hotplug bridges. > > > > > > > > > > Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable > > bridges") > > > > > Reported-by: Mario Limonciello <mario.limonciello@dell.com> > > > > > > > > Is there a bugzilla or email URL we can include here? > > > > > > Sorry it was private communication that I believe Mika is referring to in Reported- > > By here. > > > > > > You can remove the tag if you think it's inappropriate for this commit. > > > > I like to give credit whenever possible, so I wouldn't necessarily > > remove the Reported-by. > > > > But it would be very useful to also have a URL to something with more > > details, e.g., what sort of failure the user would observe, dmesg > > logs, PCI topology, etc. > > > > This information can certainly be redacted to remove any proprietary > > things that can't be made public. Usually that isn't of interest to > > structural issues like this anyway. > > It was a result of a very long communication chain, but I think I pulled > out the relevant details here if you would like a URL to include: > https://gist.github.com/superm1/100a2ed20449f684ebb84c392e35dbed Thanks Mario. I'll update changelog to include the above information as well.
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index ef5377438a1e..6cefd47556e3 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2561,7 +2561,10 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, for_each_pci_bridge(dev, bus) { cmax = max; max = pci_scan_bridge_extend(bus, dev, max, 0, 0); - used_buses += cmax - max; + /* Reserve one bus for each bridge */ + used_buses++; + if (cmax - max > 1) + used_buses += cmax - max - 1; } /* Scan bridges that need to be reconfigured */ @@ -2584,12 +2587,14 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, * bridges if any. */ buses = available_buses / hotplug_bridges; - buses = min(buses, available_buses - used_buses); + buses = min(buses, available_buses - used_buses + 1); } cmax = max; max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1); - used_buses += max - cmax; + /* One bus is already accounted so don't add it again */ + if (max - cmax > 1) + used_buses += max - cmax - 1; } /*
When distributing extra buses between hotplug bridges we need to make sure each bridge reserve at least one bus number, even if there is currently nothing connected to it. For instance ACPI hotplug may bring in additional devices to non-hotplug bridges later on. To make sure we don't run out of bus numbers for non-hotplug bridges reserve one bus number for them upfront before distributing buses for hotplug bridges. Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable bridges") Reported-by: Mario Limonciello <mario.limonciello@dell.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: stable@vger.kernel.org --- drivers/pci/probe.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)