| Message ID | 1424938344-4017-2-git-send-email-wangyijing@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Feb 26, 2015 at 04:11:55PM +0800, Yijing Wang wrote: > Pci_bus_add_devices() should not be placed in pci_scan_bus(). > Now pci device will be added to driver core once its > creation. All things left in pci_bus_add_devices() are > driver attachment and other trivial sysfs things. > Pci_scan_bus() should be the function responsible for > scanning PCI devices, not including driver attachment. > Other, some callers(m68k,unicore32,alpha) of pci_scan_bus() > will call pci_bus_size_bridges() and pci_bus_assign_resources() > after pci_scan_bus(). > > E.g. > In m68k > mcf_pci_init() > pci_scan_bus() > ... > pci_bus_add_devices() --- try to attach driver > pci_fixup_irqs() > pci_bus_size_bridges() > pci_bus_assign_resources() > > Above code flow make pci scan logic obscure, resources should > be assigned correctly before attaching driver. Because > pci_scan_bus() mostly be called in system boot path, when > before drivers are loaded(in module_init), so no pci scan > issues will occur. Most pci_scan_bus() callers additionally > call pci_bus_size_bridges() and pci_bus_assign_resources() > after pci_scan_bus(), we could rip out pci_bus_add_devices() > for better code readability. After applied this patch, > pci_scan_bus() should be used like: > > pci_scan_bus() (mandatory) > pci_fixup_irqs() (optional) > pci_bus_size_bridges() (optional) > pci_pci_bus_assign_resources() (optional) > pci_bus_add_devices() (mandatory) > > Signed-off-by: Yijing Wang <wangyijing@huawei.com> > CC: "David S. Miller" <davem@davemloft.net> > CC: Geert Uytterhoeven <geert@linux-m68k.org> > CC: Guan Xuetao <gxt@mprc.pku.edu.cn> > CC: Richard Henderson <rth@twiddle.net> > CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru> > CC: Matt Turner <mattst88@gmail.com> > CC: linux-alpha@vger.kernel.org > CC: linux-m68k@lists.linux-m68k.org > CC: sparclinux@vger.kernel.org > --- > arch/alpha/kernel/sys_nautilus.c | 1 + > arch/m68k/coldfire/pci.c | 1 + > arch/sparc/kernel/pcic.c | 2 ++ > arch/unicore32/kernel/pci.c | 11 +++-------- > drivers/pci/hotplug/ibmphp_core.c | 6 ++++-- > drivers/pci/probe.c | 1 - > 6 files changed, 11 insertions(+), 11 deletions(-) > > diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c > index 837c0fa..4ae4a40 100644 > --- a/arch/alpha/kernel/sys_nautilus.c > +++ b/arch/alpha/kernel/sys_nautilus.c > @@ -253,6 +253,7 @@ nautilus_init_pci(void) > for the root bus, so just clear it. */ > bus->self = NULL; > pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq); > + pci_bus_add_devices(bus); > } > > /* > diff --git a/arch/m68k/coldfire/pci.c b/arch/m68k/coldfire/pci.c > index df96792..d45f087 100644 > --- a/arch/m68k/coldfire/pci.c > +++ b/arch/m68k/coldfire/pci.c > @@ -319,6 +319,7 @@ static int __init mcf_pci_init(void) > pci_fixup_irqs(pci_common_swizzle, mcf_pci_map_irq); > pci_bus_size_bridges(rootbus); > pci_bus_assign_resources(rootbus); > + pci_bus_add_devices(rootbus); > return 0; > } > > diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c > index 6cc78c2..7a82fe2 100644 > --- a/arch/sparc/kernel/pcic.c > +++ b/arch/sparc/kernel/pcic.c > @@ -391,6 +391,8 @@ static void __init pcic_pbm_scan_bus(struct linux_pcic *pcic) > struct linux_pbm_info *pbm = &pcic->pbm; > > pbm->pci_bus = pci_scan_bus(pbm->pci_first_busno, &pcic_ops, pbm); > + if (pbm->pci_bus) > + pci_bus_add_devices(pbm->pci_bus); > #if 0 /* deadwood transplanted from sparc64 */ > pci_fill_in_pbm_cookies(pbm->pci_bus, pbm, pbm->prom_node); > pci_record_assignments(pbm, pbm->pci_bus); This is correct, but it should look like this instead: if (!pbm->pci_bus) return; #if 0 /* deadwood ... */ ... #endif pci_bus_add_devices(pbm->pci_bus); } That way the mainline code is the normal path, and pci_bus_add_devices() is in the correct place even if the "deadwood" code is resurrected. > diff --git a/arch/unicore32/kernel/pci.c b/arch/unicore32/kernel/pci.c > index 374a055..3d82024 100644 > --- a/arch/unicore32/kernel/pci.c > +++ b/arch/unicore32/kernel/pci.c > @@ -266,17 +266,12 @@ static int __init pci_common_init(void) > pci_fixup_irqs(pci_common_swizzle, pci_puv3_map_irq); > > if (!pci_has_flag(PCI_PROBE_ONLY)) { > - /* > - * Size the bridge windows. > - */ > + /* Size the bridge windows. */ > pci_bus_size_bridges(puv3_bus); > - > - /* > - * Assign resources. > - */ > + /* Assign resources. */ > pci_bus_assign_resources(puv3_bus); > } > - > + pci_bus_add_devices(puv3_bus); > return 0; > } > subsys_initcall(pci_common_init); > diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c > index 96c5c72..86e3bfd 100644 > --- a/drivers/pci/hotplug/ibmphp_core.c > +++ b/drivers/pci/hotplug/ibmphp_core.c > @@ -738,7 +738,7 @@ static void ibm_unconfigure_device(struct pci_func *func) > */ > static u8 bus_structure_fixup(u8 busno) > { > - struct pci_bus *bus; > + struct pci_bus *bus, *b; > struct pci_dev *dev; > u16 l; > > @@ -765,7 +765,9 @@ static u8 bus_structure_fixup(u8 busno) > (l != 0x0000) && (l != 0xffff)) { > debug("%s - Inside bus_structure_fixup()\n", > __func__); > - pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL); > + b = pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL); > + if (b) > + pci_bus_add_devices(b); Use this: if (!b) continue; pci_bus_add_devices(b); for the same reason as above. > break; > } > } > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 8d2f400..88604f2 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -2123,7 +2123,6 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, > b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources); > if (b) { > pci_scan_child_bus(b); > - pci_bus_add_devices(b); > } else { > pci_free_resource_list(&resources); > } > -- > 1.7.1 >
>> pbm->pci_bus = pci_scan_bus(pbm->pci_first_busno, &pcic_ops, pbm); >> + if (pbm->pci_bus) >> + pci_bus_add_devices(pbm->pci_bus); >> #if 0 /* deadwood transplanted from sparc64 */ >> pci_fill_in_pbm_cookies(pbm->pci_bus, pbm, pbm->prom_node); >> pci_record_assignments(pbm, pbm->pci_bus); > > This is correct, but it should look like this instead: > > if (!pbm->pci_bus) > return; > #if 0 /* deadwood ... */ > ... > #endif > pci_bus_add_devices(pbm->pci_bus); > } > > That way the mainline code is the normal path, and pci_bus_add_devices() is > in the correct place even if the "deadwood" code is resurrected. > Yes, you are right, thanks! > >> diff --git a/arch/unicore32/kernel/pci.c b/arch/unicore32/kernel/pci.c >> index 374a055..3d82024 100644 >> --- a/arch/unicore32/kernel/pci.c >> +++ b/arch/unicore32/kernel/pci.c >> @@ -266,17 +266,12 @@ static int __init pci_common_init(void) >> pci_fixup_irqs(pci_common_swizzle, pci_puv3_map_irq); >> >> if (!pci_has_flag(PCI_PROBE_ONLY)) { >> - /* >> - * Size the bridge windows. >> - */ >> + /* Size the bridge windows. */ >> pci_bus_size_bridges(puv3_bus); >> - >> - /* >> - * Assign resources. >> - */ >> + /* Assign resources. */ >> pci_bus_assign_resources(puv3_bus); >> } >> - >> + pci_bus_add_devices(puv3_bus); >> return 0; >> } >> subsys_initcall(pci_common_init); >> diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c >> index 96c5c72..86e3bfd 100644 >> --- a/drivers/pci/hotplug/ibmphp_core.c >> +++ b/drivers/pci/hotplug/ibmphp_core.c >> @@ -738,7 +738,7 @@ static void ibm_unconfigure_device(struct pci_func *func) >> */ >> static u8 bus_structure_fixup(u8 busno) >> { >> - struct pci_bus *bus; >> + struct pci_bus *bus, *b; >> struct pci_dev *dev; >> u16 l; >> >> @@ -765,7 +765,9 @@ static u8 bus_structure_fixup(u8 busno) >> (l != 0x0000) && (l != 0xffff)) { >> debug("%s - Inside bus_structure_fixup()\n", >> __func__); >> - pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL); >> + b = pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL); >> + if (b) >> + pci_bus_add_devices(b); > > Use this: > > if (!b) > continue; > pci_bus_add_devices(b); > > for the same reason as above. Will update, thanks! Thanks! Yijing. > >> break; >> } >> } >> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c >> index 8d2f400..88604f2 100644 >> --- a/drivers/pci/probe.c >> +++ b/drivers/pci/probe.c >> @@ -2123,7 +2123,6 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, >> b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources); >> if (b) { >> pci_scan_child_bus(b); >> - pci_bus_add_devices(b); >> } else { >> pci_free_resource_list(&resources); >> } >> -- >> 1.7.1 >> > > . >
diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c index 837c0fa..4ae4a40 100644 --- a/arch/alpha/kernel/sys_nautilus.c +++ b/arch/alpha/kernel/sys_nautilus.c @@ -253,6 +253,7 @@ nautilus_init_pci(void) for the root bus, so just clear it. */ bus->self = NULL; pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq); + pci_bus_add_devices(bus); } /* diff --git a/arch/m68k/coldfire/pci.c b/arch/m68k/coldfire/pci.c index df96792..d45f087 100644 --- a/arch/m68k/coldfire/pci.c +++ b/arch/m68k/coldfire/pci.c @@ -319,6 +319,7 @@ static int __init mcf_pci_init(void) pci_fixup_irqs(pci_common_swizzle, mcf_pci_map_irq); pci_bus_size_bridges(rootbus); pci_bus_assign_resources(rootbus); + pci_bus_add_devices(rootbus); return 0; } diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c index 6cc78c2..7a82fe2 100644 --- a/arch/sparc/kernel/pcic.c +++ b/arch/sparc/kernel/pcic.c @@ -391,6 +391,8 @@ static void __init pcic_pbm_scan_bus(struct linux_pcic *pcic) struct linux_pbm_info *pbm = &pcic->pbm; pbm->pci_bus = pci_scan_bus(pbm->pci_first_busno, &pcic_ops, pbm); + if (pbm->pci_bus) + pci_bus_add_devices(pbm->pci_bus); #if 0 /* deadwood transplanted from sparc64 */ pci_fill_in_pbm_cookies(pbm->pci_bus, pbm, pbm->prom_node); pci_record_assignments(pbm, pbm->pci_bus); diff --git a/arch/unicore32/kernel/pci.c b/arch/unicore32/kernel/pci.c index 374a055..3d82024 100644 --- a/arch/unicore32/kernel/pci.c +++ b/arch/unicore32/kernel/pci.c @@ -266,17 +266,12 @@ static int __init pci_common_init(void) pci_fixup_irqs(pci_common_swizzle, pci_puv3_map_irq); if (!pci_has_flag(PCI_PROBE_ONLY)) { - /* - * Size the bridge windows. - */ + /* Size the bridge windows. */ pci_bus_size_bridges(puv3_bus); - - /* - * Assign resources. - */ + /* Assign resources. */ pci_bus_assign_resources(puv3_bus); } - + pci_bus_add_devices(puv3_bus); return 0; } subsys_initcall(pci_common_init); diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c index 96c5c72..86e3bfd 100644 --- a/drivers/pci/hotplug/ibmphp_core.c +++ b/drivers/pci/hotplug/ibmphp_core.c @@ -738,7 +738,7 @@ static void ibm_unconfigure_device(struct pci_func *func) */ static u8 bus_structure_fixup(u8 busno) { - struct pci_bus *bus; + struct pci_bus *bus, *b; struct pci_dev *dev; u16 l; @@ -765,7 +765,9 @@ static u8 bus_structure_fixup(u8 busno) (l != 0x0000) && (l != 0xffff)) { debug("%s - Inside bus_structure_fixup()\n", __func__); - pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL); + b = pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL); + if (b) + pci_bus_add_devices(b); break; } } diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8d2f400..88604f2 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2123,7 +2123,6 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources); if (b) { pci_scan_child_bus(b); - pci_bus_add_devices(b); } else { pci_free_resource_list(&resources); }
Pci_bus_add_devices() should not be placed in pci_scan_bus(). Now pci device will be added to driver core once its creation. All things left in pci_bus_add_devices() are driver attachment and other trivial sysfs things. Pci_scan_bus() should be the function responsible for scanning PCI devices, not including driver attachment. Other, some callers(m68k,unicore32,alpha) of pci_scan_bus() will call pci_bus_size_bridges() and pci_bus_assign_resources() after pci_scan_bus(). E.g. In m68k mcf_pci_init() pci_scan_bus() ... pci_bus_add_devices() --- try to attach driver pci_fixup_irqs() pci_bus_size_bridges() pci_bus_assign_resources() Above code flow make pci scan logic obscure, resources should be assigned correctly before attaching driver. Because pci_scan_bus() mostly be called in system boot path, when before drivers are loaded(in module_init), so no pci scan issues will occur. Most pci_scan_bus() callers additionally call pci_bus_size_bridges() and pci_bus_assign_resources() after pci_scan_bus(), we could rip out pci_bus_add_devices() for better code readability. After applied this patch, pci_scan_bus() should be used like: pci_scan_bus() (mandatory) pci_fixup_irqs() (optional) pci_bus_size_bridges() (optional) pci_pci_bus_assign_resources() (optional) pci_bus_add_devices() (mandatory) Signed-off-by: Yijing Wang <wangyijing@huawei.com> CC: "David S. Miller" <davem@davemloft.net> CC: Geert Uytterhoeven <geert@linux-m68k.org> CC: Guan Xuetao <gxt@mprc.pku.edu.cn> CC: Richard Henderson <rth@twiddle.net> CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru> CC: Matt Turner <mattst88@gmail.com> CC: linux-alpha@vger.kernel.org CC: linux-m68k@lists.linux-m68k.org CC: sparclinux@vger.kernel.org --- arch/alpha/kernel/sys_nautilus.c | 1 + arch/m68k/coldfire/pci.c | 1 + arch/sparc/kernel/pcic.c | 2 ++ arch/unicore32/kernel/pci.c | 11 +++-------- drivers/pci/hotplug/ibmphp_core.c | 6 ++++-- drivers/pci/probe.c | 1 - 6 files changed, 11 insertions(+), 11 deletions(-)