| Message ID | 1469158828-4179-1-git-send-email-keith.busch@intel.com |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, Jul 21, 2016 at 09:40:28PM -0600, Keith Busch wrote: > A user may hot add a switch requiring more than one bus to enumerate. This > previously required a system reboot if BIOS did not sufficiently pad > the bus resource, which they frequently don't do. This patch allows > a user specify the minimum number of resources to reserve for a hotplug > bridge's subordinate busses so rebooting won't be necessary. > > The default is 1, which is equivalent to previous behavior. > > Signed-off-by: Keith Busch <keith.busch@intel.com> Applied to pci/hotplug for v4.8, thanks, Keith! > --- > Documentation/kernel-parameters.txt | 3 +++ > drivers/pci/pci.c | 8 ++++++++ > drivers/pci/probe.c | 9 +++++++++ > include/linux/pci.h | 1 + > 4 files changed, 21 insertions(+) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index 82b42c9..ce4b45b 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -3016,6 +3016,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > hpmemsize=nn[KMG] The fixed amount of bus space which is > reserved for hotplug bridge's memory window. > Default size is 2 megabytes. > + hpbussize=nn The minimum amount of additional bus > + space which is reserved for hotplug bridge's > + bus window. Default is 1. > realloc= Enable/disable reallocating PCI bridge resources > if allocations done by BIOS are too small to > accommodate resources required by all child > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index c8b4dbd..7d290f7 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -81,6 +81,9 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE; > unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE; > unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE; > > +#define DEFAULT_HOTPLUG_BUS_SIZE (1) > +unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; > + > enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT; > > /* > @@ -5021,6 +5024,11 @@ static int __init pci_setup(char *str) > pci_hotplug_io_size = memparse(str + 9, &str); > } else if (!strncmp(str, "hpmemsize=", 10)) { > pci_hotplug_mem_size = memparse(str + 10, &str); > + } else if (!strncmp(str, "hpbussize=", 10)) { > + pci_hotplug_bus_size = > + simple_strtoul(str + 10, &str, 0); > + if (pci_hotplug_bus_size > 0xff) > + pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; > } else if (!strncmp(str, "pcie_bus_tune_off", 17)) { > pcie_bus_config = PCIE_BUS_TUNE_OFF; > } else if (!strncmp(str, "pcie_bus_safe", 13)) { > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 8e3ef72..9454396 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -2077,6 +2077,15 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) > } > > /* > + * Make sure a hot plug bridge has at least the minimum requested > + * number of busses. > + */ > + if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) { > + if (max - bus->busn_res.start < pci_hotplug_bus_size - 1) > + max = bus->busn_res.start + pci_hotplug_bus_size - 1; > + } > + > + /* > * We've scanned the bus and so we know all about what's on > * the other side of any bridges that may be on this bus plus > * any devices. > diff --git a/include/linux/pci.h b/include/linux/pci.h > index b67e4df..0c28325 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1706,6 +1706,7 @@ extern u8 pci_cache_line_size; > > extern unsigned long pci_hotplug_io_size; > extern unsigned long pci_hotplug_mem_size; > +extern unsigned long pci_hotplug_bus_size; > > /* Architecture-specific versions may override these (weak) */ > void pcibios_disable_device(struct pci_dev *dev); > -- > 2.7.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 82b42c9..ce4b45b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3016,6 +3016,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. hpmemsize=nn[KMG] The fixed amount of bus space which is reserved for hotplug bridge's memory window. Default size is 2 megabytes. + hpbussize=nn The minimum amount of additional bus + space which is reserved for hotplug bridge's + bus window. Default is 1. realloc= Enable/disable reallocating PCI bridge resources if allocations done by BIOS are too small to accommodate resources required by all child diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index c8b4dbd..7d290f7 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -81,6 +81,9 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE; unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE; unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE; +#define DEFAULT_HOTPLUG_BUS_SIZE (1) +unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; + enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT; /* @@ -5021,6 +5024,11 @@ static int __init pci_setup(char *str) pci_hotplug_io_size = memparse(str + 9, &str); } else if (!strncmp(str, "hpmemsize=", 10)) { pci_hotplug_mem_size = memparse(str + 10, &str); + } else if (!strncmp(str, "hpbussize=", 10)) { + pci_hotplug_bus_size = + simple_strtoul(str + 10, &str, 0); + if (pci_hotplug_bus_size > 0xff) + pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; } else if (!strncmp(str, "pcie_bus_tune_off", 17)) { pcie_bus_config = PCIE_BUS_TUNE_OFF; } else if (!strncmp(str, "pcie_bus_safe", 13)) { diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8e3ef72..9454396 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2077,6 +2077,15 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) } /* + * Make sure a hot plug bridge has at least the minimum requested + * number of busses. + */ + if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) { + if (max - bus->busn_res.start < pci_hotplug_bus_size - 1) + max = bus->busn_res.start + pci_hotplug_bus_size - 1; + } + + /* * We've scanned the bus and so we know all about what's on * the other side of any bridges that may be on this bus plus * any devices. diff --git a/include/linux/pci.h b/include/linux/pci.h index b67e4df..0c28325 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1706,6 +1706,7 @@ extern u8 pci_cache_line_size; extern unsigned long pci_hotplug_io_size; extern unsigned long pci_hotplug_mem_size; +extern unsigned long pci_hotplug_bus_size; /* Architecture-specific versions may override these (weak) */ void pcibios_disable_device(struct pci_dev *dev);
A user may hot add a switch requiring more than one bus to enumerate. This previously required a system reboot if BIOS did not sufficiently pad the bus resource, which they frequently don't do. This patch allows a user specify the minimum number of resources to reserve for a hotplug bridge's subordinate busses so rebooting won't be necessary. The default is 1, which is equivalent to previous behavior. Signed-off-by: Keith Busch <keith.busch@intel.com> --- Documentation/kernel-parameters.txt | 3 +++ drivers/pci/pci.c | 8 ++++++++ drivers/pci/probe.c | 9 +++++++++ include/linux/pci.h | 1 + 4 files changed, 21 insertions(+)