| Message ID | 1425868467-9667-7-git-send-email-wangyijing@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Mar 09, 2015 at 10:34:03AM +0800, Yijing Wang wrote: > Currently, we use int type for bus number in > pci_create_root_bus(), pci_scan_root_bus() and > pci_scan_bus_legacy. Because PCI bus number > always <= 255, so we could change the bus number > argument type to u32, and combine PCI domain and > bus number in one. This makes no sense. Or rather, it only states the obvious: an 8-bit value and a 16-bit value will both fit in a 32-bit value. But it doesn't say *why* you think it's a good idea to pass a single value that contains both domain and bus numbers. The obvious thing is to pass two separate values, and you don't say why passing a single combined value is better. Also see whitespace mistakes below. I get a little testy when people don't follow the whitespace convention of neighboring lines because if people are sloppy about whitespace I assume they're sloppy about the code. > Also add a domain member in > pci_host_bridge to save domain number. Finally, > we could eliminate lots of the platform specific > pci_domain_nr() in the last of the series. > > Signed-off-by: Yijing Wang <wangyijing@huawei.com> > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > --- > drivers/pci/probe.c | 16 +++++++++------- > include/linux/pci.h | 7 ++++--- > include/uapi/linux/pci.h | 3 +++ > 3 files changed, 16 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 187fa54..3d6befd 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1890,7 +1890,7 @@ void __weak pcibios_remove_bus(struct pci_bus *bus) > { > } > > -struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > +struct pci_bus *pci_create_root_bus(struct device *parent, u32 db, > struct pci_ops *ops, void *sysdata, struct list_head *resources) > { > int error; > @@ -1901,6 +1901,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > resource_size_t offset; > char bus_addr[64]; > char *fmt; > + u8 bus = PCI_BUSNUM(db); Whitespace botch. > > b = pci_alloc_bus(NULL); > if (!b) > @@ -1921,6 +1922,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > if (!bridge) > goto err_out; > > + bridge->domain = PCI_DOMAIN(db); > bridge->dev.parent = parent; > bridge->dev.release = pci_release_host_bridge_dev; > dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus); > @@ -2058,7 +2060,7 @@ void pci_bus_release_busn_res(struct pci_bus *b) > res, ret ? "can not be" : "is"); > } > > -struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, > +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db, > struct pci_ops *ops, void *sysdata, struct list_head *resources) > { > struct resource_entry *window; > @@ -2072,15 +2074,15 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, > break; > } > > - b = pci_create_root_bus(parent, bus, ops, sysdata, resources); > + b = pci_create_root_bus(parent, db, ops, sysdata, resources); > if (!b) > return NULL; > > if (!found) { > dev_info(&b->dev, > "No busn resource found for root bus, will use [bus %02x-ff]\n", > - bus); > - pci_bus_insert_busn_res(b, bus, 255); > + PCI_BUSNUM(db)); > + pci_bus_insert_busn_res(b, PCI_BUSNUM(db), 255); > } > > max = pci_scan_child_bus(b); > @@ -2092,7 +2094,7 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, > } > EXPORT_SYMBOL(pci_scan_root_bus); > > -struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, > +struct pci_bus *pci_scan_bus(u32 db, struct pci_ops *ops, > void *sysdata) > { > LIST_HEAD(resources); > @@ -2101,7 +2103,7 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, > pci_add_resource(&resources, &ioport_resource); > pci_add_resource(&resources, &iomem_resource); > pci_add_resource(&resources, &busn_resource); > - b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources); > + b = pci_create_root_bus(NULL, db, ops, sysdata, &resources); > if (b) { > pci_scan_child_bus(b); > } else { > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 36effb8..8b3d245 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -401,6 +401,7 @@ static inline int pci_channel_offline(struct pci_dev *pdev) > } > > struct pci_host_bridge { > + u16 domain; Please follow the existing whitespace convention, i.e., use a space, not a tab, between "u16 domain". > struct device dev; > struct pci_bus *bus; /* root bus */ > struct list_head windows; /* resource_entry */ > @@ -769,14 +770,14 @@ void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res, > void pcibios_scan_specific_bus(int busn); > struct pci_bus *pci_find_bus(int domain, int busnr); > void pci_bus_add_devices(const struct pci_bus *bus); > -struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata); > -struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > +struct pci_bus *pci_scan_bus(u32 dombus, struct pci_ops *ops, void *sysdata); > +struct pci_bus *pci_create_root_bus(struct device *parent, u32 dombus, > struct pci_ops *ops, void *sysdata, > struct list_head *resources); > int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax); > int pci_bus_update_busn_res_end(struct pci_bus *b, int busmax); > void pci_bus_release_busn_res(struct pci_bus *b); > -struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, > +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 dombus, > struct pci_ops *ops, void *sysdata, > struct list_head *resources); > struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, > diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h > index 3c292bc..89c6f15 100644 > --- a/include/uapi/linux/pci.h > +++ b/include/uapi/linux/pci.h > @@ -30,6 +30,9 @@ > #define PCI_DEVFN(slot, func) ((((slot) & 0x1f) << 3) | ((func) & 0x07)) > #define PCI_SLOT(devfn) (((devfn) >> 3) & 0x1f) > #define PCI_FUNC(devfn) ((devfn) & 0x07) > +#define PCI_DOMAIN(db) ((db) >> 16) > +#define PCI_BUSNUM(db) ((db) & 0xffff) > +#define PCI_DOMBUS(domain, bus) (((domain) << 16) | (bus)) > > /* Ioctls for /proc/bus/pci/X/Y nodes. */ > #define PCIIOC_BASE ('P' << 24 | 'C' << 16 | 'I' << 8) > -- > 1.7.1 > > -- > 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
On 2015/3/12 9:29, Bjorn Helgaas wrote: > On Mon, Mar 09, 2015 at 10:34:03AM +0800, Yijing Wang wrote: >> Currently, we use int type for bus number in >> pci_create_root_bus(), pci_scan_root_bus() and >> pci_scan_bus_legacy. Because PCI bus number >> always <= 255, so we could change the bus number >> argument type to u32, and combine PCI domain and >> bus number in one. > > This makes no sense. Or rather, it only states the obvious: an 8-bit value > and a 16-bit value will both fit in a 32-bit value. But it doesn't say > *why* you think it's a good idea to pass a single value that contains both > domain and bus numbers. The obvious thing is to pass two separate values, > and you don't say why passing a single combined value is better. Sorry for my poor description for this patch, I combined the domain and bus, because I think now we have too many args at pci_scan_root_bus() or other scan functions, struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, struct pci_ops *ops, void *sysdata, struct list_head *resources) Now we have five args yet, plus the new introduced domain and pci_host_bridge_ops, it will become 7. I thought introduced a new structure which contain the necessary info to scan root bus/ host bridge, E.g struct pci_scan_info { int bus; struct device *parent; struct pci_ops *ops; void *sysdata; struct list_head *resource; int domain; struct pci_host_bridge_ops; } Do you like this one or keep it like now ? pci_scan_root_bus(struct device *parent, int domain, int bus, struct pci_ops *ops, void *sysdata, struct list_head *resources, struct pci_host_bridge_ops *ops) > > Also see whitespace mistakes below. I get a little testy when people don't > follow the whitespace convention of neighboring lines because if people are > sloppy about whitespace I assume they're sloppy about the code. > Sorry, I would be more careful. >> int error; >> @@ -1901,6 +1901,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, >> resource_size_t offset; >> char bus_addr[64]; >> char *fmt; >> + u8 bus = PCI_BUSNUM(db); > > Whitespace botch. > >> >> b = pci_alloc_bus(NULL); >> if (!b) >> @@ -1921,6 +1922,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, >> if (!bridge) >> goto err_out; >> >> + bridge->domain = PCI_DOMAIN(db); >> bridge->dev.parent = parent; >> bridge->dev.release = pci_release_host_bridge_dev; >> dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus); >> @@ -2058,7 +2060,7 @@ void pci_bus_release_busn_res(struct pci_bus *b) >> res, ret ? "can not be" : "is"); >> } >> >> -struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, >> +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db, >> struct pci_ops *ops, void *sysdata, struct list_head *resources) >> { >> struct resource_entry *window; >> @@ -2072,15 +2074,15 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, >> break; >> } >> >> - b = pci_create_root_bus(parent, bus, ops, sysdata, resources); >> + b = pci_create_root_bus(parent, db, ops, sysdata, resources); >> if (!b) >> return NULL; >> >> if (!found) { >> dev_info(&b->dev, >> "No busn resource found for root bus, will use [bus %02x-ff]\n", >> - bus); >> - pci_bus_insert_busn_res(b, bus, 255); >> + PCI_BUSNUM(db)); >> + pci_bus_insert_busn_res(b, PCI_BUSNUM(db), 255); >> } >> >> max = pci_scan_child_bus(b); >> @@ -2092,7 +2094,7 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, >> } >> EXPORT_SYMBOL(pci_scan_root_bus); >> >> -struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, >> +struct pci_bus *pci_scan_bus(u32 db, struct pci_ops *ops, >> void *sysdata) >> { >> LIST_HEAD(resources); >> @@ -2101,7 +2103,7 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, >> pci_add_resource(&resources, &ioport_resource); >> pci_add_resource(&resources, &iomem_resource); >> pci_add_resource(&resources, &busn_resource); >> - b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources); >> + b = pci_create_root_bus(NULL, db, ops, sysdata, &resources); >> if (b) { >> pci_scan_child_bus(b); >> } else { >> diff --git a/include/linux/pci.h b/include/linux/pci.h >> index 36effb8..8b3d245 100644 >> --- a/include/linux/pci.h >> +++ b/include/linux/pci.h >> @@ -401,6 +401,7 @@ static inline int pci_channel_offline(struct pci_dev *pdev) >> } >> >> struct pci_host_bridge { >> + u16 domain; > > Please follow the existing whitespace convention, i.e., use a space, not a > tab, between "u16 domain". > >> struct device dev; >> struct pci_bus *bus; /* root bus */ >> struct list_head windows; /* resource_entry */ >> @@ -769,14 +770,14 @@ void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res, >> void pcibios_scan_specific_bus(int busn); >> struct pci_bus *pci_find_bus(int domain, int busnr); >> void pci_bus_add_devices(const struct pci_bus *bus); >> -struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata); >> -struct pci_bus *pci_create_root_bus(struct device *parent, int bus, >> +struct pci_bus *pci_scan_bus(u32 dombus, struct pci_ops *ops, void *sysdata); >> +struct pci_bus *pci_create_root_bus(struct device *parent, u32 dombus, >> struct pci_ops *ops, void *sysdata, >> struct list_head *resources); >> int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax); >> int pci_bus_update_busn_res_end(struct pci_bus *b, int busmax); >> void pci_bus_release_busn_res(struct pci_bus *b); >> -struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, >> +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 dombus, >> struct pci_ops *ops, void *sysdata, >> struct list_head *resources); >> struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, >> diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h >> index 3c292bc..89c6f15 100644 >> --- a/include/uapi/linux/pci.h >> +++ b/include/uapi/linux/pci.h >> @@ -30,6 +30,9 @@ >> #define PCI_DEVFN(slot, func) ((((slot) & 0x1f) << 3) | ((func) & 0x07)) >> #define PCI_SLOT(devfn) (((devfn) >> 3) & 0x1f) >> #define PCI_FUNC(devfn) ((devfn) & 0x07) >> +#define PCI_DOMAIN(db) ((db) >> 16) >> +#define PCI_BUSNUM(db) ((db) & 0xffff) >> +#define PCI_DOMBUS(domain, bus) (((domain) << 16) | (bus)) >> >> /* Ioctls for /proc/bus/pci/X/Y nodes. */ >> #define PCIIOC_BASE ('P' << 24 | 'C' << 16 | 'I' << 8) >> -- >> 1.7.1 >> >> -- >> 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 > > . >
On Thu, Mar 12, 2015 at 08:14:40PM +0800, Yijing Wang wrote: > On 2015/3/12 9:29, Bjorn Helgaas wrote: > > On Mon, Mar 09, 2015 at 10:34:03AM +0800, Yijing Wang wrote: > >> Currently, we use int type for bus number in > >> pci_create_root_bus(), pci_scan_root_bus() and > >> pci_scan_bus_legacy. Because PCI bus number > >> always <= 255, so we could change the bus number > >> argument type to u32, and combine PCI domain and > >> bus number in one. > > > > This makes no sense. Or rather, it only states the obvious: an 8-bit value > > and a 16-bit value will both fit in a 32-bit value. But it doesn't say > > *why* you think it's a good idea to pass a single value that contains both > > domain and bus numbers. The obvious thing is to pass two separate values, > > and you don't say why passing a single combined value is better. > > Sorry for my poor description for this patch, I combined the domain and bus, because > I think now we have too many args at pci_scan_root_bus() or other scan functions, > > struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, > struct pci_ops *ops, void *sysdata, struct list_head *resources) > > Now we have five args yet, plus the new introduced domain and pci_host_bridge_ops, > it will become 7. > > I thought introduced a new structure which contain the necessary info to scan root bus/ host bridge, > > E.g > > struct pci_scan_info { > int bus; > struct device *parent; > struct pci_ops *ops; > void *sysdata; > struct list_head *resource; > int domain; > struct pci_host_bridge_ops; > } > > Do you like this one or keep it like now ? > > pci_scan_root_bus(struct device *parent, int domain, int bus, > struct pci_ops *ops, void *sysdata, struct list_head *resources, struct pci_host_bridge_ops *ops) I don't think reducing the number of arguments is a good argument for squashing some of them together. I don't really want to add a structure like that because it adds management complexity for all the callers because it contains per-bridge things (bus, parent, domain, resource, sysdata). Things like struct pci_ops and struct pci_host_bridge_ops are much simpler because drivers can statically allocate a single copy and use it for multiple devices. I think it might make sense to put the struct pci_ops pointer inside struct pci_host_bridge_ops. That would get rid of one of the arguments. You might also be able to get rid of the "bus" argument, since the caller should be passing an IORESOURCE_BUS resource in the resource list, and "bus" should be the same as res->start. Bjorn
>> struct pci_scan_info { >> int bus; >> struct device *parent; >> struct pci_ops *ops; >> void *sysdata; >> struct list_head *resource; >> int domain; >> struct pci_host_bridge_ops; >> } >> >> Do you like this one or keep it like now ? >> >> pci_scan_root_bus(struct device *parent, int domain, int bus, >> struct pci_ops *ops, void *sysdata, struct list_head *resources, struct pci_host_bridge_ops *ops) > > I don't think reducing the number of arguments is a good argument for > squashing some of them together. > > I don't really want to add a structure like that because it adds management > complexity for all the callers because it contains per-bridge things (bus, > parent, domain, resource, sysdata). Things like struct pci_ops and struct > pci_host_bridge_ops are much simpler because drivers can statically > allocate a single copy and use it for multiple devices. > > I think it might make sense to put the struct pci_ops pointer inside struct > pci_host_bridge_ops. That would get rid of one of the arguments. > > You might also be able to get rid of the "bus" argument, since the caller > should be passing an IORESOURCE_BUS resource in the resource list, and > "bus" should be the same as res->start. I think this make sense, I will try to find a better solution. Thanks! Yijing. > > Bjorn > > . >
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 187fa54..3d6befd 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1890,7 +1890,7 @@ void __weak pcibios_remove_bus(struct pci_bus *bus) { } -struct pci_bus *pci_create_root_bus(struct device *parent, int bus, +struct pci_bus *pci_create_root_bus(struct device *parent, u32 db, struct pci_ops *ops, void *sysdata, struct list_head *resources) { int error; @@ -1901,6 +1901,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, resource_size_t offset; char bus_addr[64]; char *fmt; + u8 bus = PCI_BUSNUM(db); b = pci_alloc_bus(NULL); if (!b) @@ -1921,6 +1922,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, if (!bridge) goto err_out; + bridge->domain = PCI_DOMAIN(db); bridge->dev.parent = parent; bridge->dev.release = pci_release_host_bridge_dev; dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus); @@ -2058,7 +2060,7 @@ void pci_bus_release_busn_res(struct pci_bus *b) res, ret ? "can not be" : "is"); } -struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db, struct pci_ops *ops, void *sysdata, struct list_head *resources) { struct resource_entry *window; @@ -2072,15 +2074,15 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, break; } - b = pci_create_root_bus(parent, bus, ops, sysdata, resources); + b = pci_create_root_bus(parent, db, ops, sysdata, resources); if (!b) return NULL; if (!found) { dev_info(&b->dev, "No busn resource found for root bus, will use [bus %02x-ff]\n", - bus); - pci_bus_insert_busn_res(b, bus, 255); + PCI_BUSNUM(db)); + pci_bus_insert_busn_res(b, PCI_BUSNUM(db), 255); } max = pci_scan_child_bus(b); @@ -2092,7 +2094,7 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, } EXPORT_SYMBOL(pci_scan_root_bus); -struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, +struct pci_bus *pci_scan_bus(u32 db, struct pci_ops *ops, void *sysdata) { LIST_HEAD(resources); @@ -2101,7 +2103,7 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, pci_add_resource(&resources, &ioport_resource); pci_add_resource(&resources, &iomem_resource); pci_add_resource(&resources, &busn_resource); - b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources); + b = pci_create_root_bus(NULL, db, ops, sysdata, &resources); if (b) { pci_scan_child_bus(b); } else { diff --git a/include/linux/pci.h b/include/linux/pci.h index 36effb8..8b3d245 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -401,6 +401,7 @@ static inline int pci_channel_offline(struct pci_dev *pdev) } struct pci_host_bridge { + u16 domain; struct device dev; struct pci_bus *bus; /* root bus */ struct list_head windows; /* resource_entry */ @@ -769,14 +770,14 @@ void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res, void pcibios_scan_specific_bus(int busn); struct pci_bus *pci_find_bus(int domain, int busnr); void pci_bus_add_devices(const struct pci_bus *bus); -struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata); -struct pci_bus *pci_create_root_bus(struct device *parent, int bus, +struct pci_bus *pci_scan_bus(u32 dombus, struct pci_ops *ops, void *sysdata); +struct pci_bus *pci_create_root_bus(struct device *parent, u32 dombus, struct pci_ops *ops, void *sysdata, struct list_head *resources); int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax); int pci_bus_update_busn_res_end(struct pci_bus *b, int busmax); void pci_bus_release_busn_res(struct pci_bus *b); -struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 dombus, struct pci_ops *ops, void *sysdata, struct list_head *resources); struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h index 3c292bc..89c6f15 100644 --- a/include/uapi/linux/pci.h +++ b/include/uapi/linux/pci.h @@ -30,6 +30,9 @@ #define PCI_DEVFN(slot, func) ((((slot) & 0x1f) << 3) | ((func) & 0x07)) #define PCI_SLOT(devfn) (((devfn) >> 3) & 0x1f) #define PCI_FUNC(devfn) ((devfn) & 0x07) +#define PCI_DOMAIN(db) ((db) >> 16) +#define PCI_BUSNUM(db) ((db) & 0xffff) +#define PCI_DOMBUS(domain, bus) (((domain) << 16) | (bus)) /* Ioctls for /proc/bus/pci/X/Y nodes. */ #define PCIIOC_BASE ('P' << 24 | 'C' << 16 | 'I' << 8)