Re: [PATCH 04/24] PCI: Add busn_res operation functions
From: Bjorn Helgaas <bhelgaas@google.com>
Date: 2012-02-06 18:59:36
Also in:
linux-pci, lkml
On Sat, Feb 4, 2012 at 10:57 PM, Yinghai Lu [off-list ref] wrote:
quoted hunk ↗ jump to hunk
will use them insert/update busn res in pci_bus Signed-off-by: Yinghai Lu <yinghai@kernel.org> --- drivers/pci/probe.c | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 3 +++ 2 files changed, 45 insertions(+), 0 deletions(-)diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index a114173..8d4de5e 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c@@ -1622,6 +1622,48 @@ err_out:return NULL; } +void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max) +{ + struct resource *res = &b->busn_res; + struct resource *parent_res = &iobusn_resource; + int ret; + + res->start = busn(pci_domain_nr(b), bus); + res->end = busn(pci_domain_nr(b), bus_max); + res->flags = IORESOURCE_BUS; + + if (!pci_is_root_bus(b)) + parent_res = &b->parent->busn_res; + + ret = insert_resource(parent_res, res); + + dev_printk(KERN_DEBUG, &b->dev, + "busn_res: %pR %s inserted under %pR\n", + res, ret ? "can not be" : "is", parent_res); +} + +void pci_bus_update_busn_res_end(struct pci_bus *b, int bus_max) +{ + struct resource *res = &b->busn_res; + struct resource old_res = *res; + + res->end = busn_update_bus_nr(res->end, bus_max);
I think this design is a mistake. Here's what you're doing: - initialize struct resource (keys are "start" and "end") - insert into tree (placed in tree by kernel/resource.c based on "start" and "end") - update "end" You "know" in this case that the update is safe because the caller has validated "bus_max." But that still breaks the kernel/resource.c encapsulation. If we change the kernel/resource.c implementation, this code might break. I think it would be better to remove the bus resource from the tree, change its "end," then re-insert it.
quoted hunk ↗ jump to hunk
+ dev_printk(KERN_DEBUG, &b->dev, + "busn_res: %pR end updated to %pR\n", + &old_res, res); +} + +void pci_bus_release_busn_res(struct pci_bus *b) +{ + struct resource *res = &b->busn_res; + int ret; + + ret = release_resource(res); + dev_printk(KERN_DEBUG, &b->dev, + "busn_res: %pR %s released\n", + res, ret ? "can not be" : "is"); +} + struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus, struct pci_ops *ops, void *sysdata, struct list_head *resources) {diff --git a/include/linux/pci.h b/include/linux/pci.h index 94ad468..3da935c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h@@ -665,6 +665,9 @@ 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_ops *ops, void *sysdata, struct list_head *resources); +void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax); +void 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 * __devinit pci_scan_root_bus(struct device *parent, int bus, struct pci_ops *ops, void *sysdata, struct list_head *resources); -- 1.7.7