[PATCH v2 01/30] PCI: Rip out pci_bus_add_devices() from pci_scan_bus()

Yijing Wang
2015-01-21T02:32:29Z

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);
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 23212f8..053c0f4 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