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author | jhb <jhb@FreeBSD.org> | 2006-01-20 21:59:13 +0000 |
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committer | jhb <jhb@FreeBSD.org> | 2006-01-20 21:59:13 +0000 |
commit | 76788b459e8439347a498ab900465722b7a187cf (patch) | |
tree | eec17a9b197066f7f038be2d63c8c1ea557d7d1d /sys/kern | |
parent | c959fdcd4e208eb80f6fb484d901544144df4ed5 (diff) | |
download | FreeBSD-src-76788b459e8439347a498ab900465722b7a187cf.zip FreeBSD-src-76788b459e8439347a498ab900465722b7a187cf.tar.gz |
When loading a driver that is a subclass of another driver don't set the
devclass's parent pointer if the two drivers share the same devclass. This
can happen if the drivers use the same new-bus name. For example, we
currently have 3 drivers that use the name "pci": the generic PCI bus
driver, the ACPI PCI bus driver, and the OpenFirmware PCI bus driver. If
the ACPI PCI bus driver was defined as a subclass of the generic PCI bus
driver, then without this check the "pci" devclass would point to itself
as its parent and device_probe_child() would spin forever when it
encountered the first PCI device that did have a matching driver.
Reviewed by: dfr, imp, new-bus@
Diffstat (limited to 'sys/kern')
-rw-r--r-- | sys/kern/subr_bus.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c index 7f7bb93..b19be54 100644 --- a/sys/kern/subr_bus.c +++ b/sys/kern/subr_bus.c @@ -781,7 +781,17 @@ devclass_find_internal(const char *classname, const char *parentname, bus_data_generation_update(); } - if (parentname && dc && !dc->parent) { + + /* + * If a parent class is specified, then set that as our parent so + * that this devclass will support drivers for the parent class as + * well. If the parent class has the same name don't do this though + * as it creates a cycle that can trigger an infinite loop in + * device_probe_child() if a device exists for which there is no + * suitable driver. + */ + if (parentname && dc && !dc->parent && + strcmp(classname, parentname) != 0) { dc->parent = devclass_find_internal(parentname, 0, FALSE); } |