PCI: Multiprobe sanitizer

There are numerous drivers that can use multithreaded probing but having
some kind of global flag as the way to control this makes migration to
threaded probing hard and since it enables it everywhere and is almost
as likely to cause serious pain as holding a clog dance in a minefield.

If we have a pci_driver multithread_probe flag to inherit you can turn
it on for one driver at a time.

From playing so far however I think we need a different model at the
device layer which serializes until the called probe function says "ok
you can start another one now". That would need some kind of flag and
semaphore plus a helper function.

Anyway in the absence of that this is a starting point to usefully play
with this stuff

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 309629e03baea44a940235b4e5ebd5e691234764..b1c0c707d96ccc6e713042b1d67167609199c723 100644 (file)
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -421,7 +421,11 @@ int __pci_register_driver(struct pci_driver *drv, struct module *owner)
        drv->driver.bus = &pci_bus_type;
        drv->driver.owner = owner;
        drv->driver.kobj.ktype = &pci_driver_kobj_type;
-       drv->driver.multithread_probe = pci_multithread_probe;
+
+       if (pci_multithread_probe)
+               drv->driver.multithread_probe = pci_multithread_probe;
+       else
+               drv->driver.multithread_probe = drv->multithread_probe;
 
        spin_lock_init(&drv->dynids.lock);
        INIT_LIST_HEAD(&drv->dynids.list);

diff --git a/include/linux/pci.h b/include/linux/pci.h
index c9bb7bee52c73dc33736f8eaec148b4d1e50ed5a..549d8410974b6e09dd25642d85fdb6f55e22db7e 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -356,6 +356,8 @@ struct pci_driver {
        struct pci_error_handlers *err_handler;
        struct device_driver    driver;
        struct pci_dynids dynids;
+
+       int multithread_probe;
 };
 
 #define        to_pci_driver(drv) container_of(drv,struct pci_driver, driver)