On 10/08/11 10:33, Manohar Vanga wrote: > This patch adds functions that allow for reference counting > bridge modules. The patch introduces the functions > 'vme_bridge_get()' and 'vme_bridge_put()'. > > The functions are automatically called during .probe and .remove > for drivers. > > This patch is based on the changes introduced by Emilio G. Cota > in the patch: > > https://lkml.org/lkml/2010/10/25/492 > > Signed-off-by: Manohar Vanga <manohar.vanga@xxxxxxx> > --- > drivers/staging/vme/bridges/vme_ca91cx42.c | 2 + > drivers/staging/vme/bridges/vme_tsi148.c | 2 + > drivers/staging/vme/vme.c | 54 ++++++++++++++++++++++++++++ > drivers/staging/vme/vme.h | 2 + > drivers/staging/vme/vme_bridge.h | 1 + > 5 files changed, 61 insertions(+), 0 deletions(-) > > diff --git a/drivers/staging/vme/bridges/vme_ca91cx42.c b/drivers/staging/vme/bridges/vme_ca91cx42.c > index 15a0b19..2f9c22b 100644 > --- a/drivers/staging/vme/bridges/vme_ca91cx42.c > +++ b/drivers/staging/vme/bridges/vme_ca91cx42.c > @@ -1680,6 +1680,8 @@ static int ca91cx42_probe(struct pci_dev *pdev, const struct pci_device_id *id) > ca91cx42_bridge->parent = &pdev->dev; > strcpy(ca91cx42_bridge->name, driver_name); > > + ca91cx42_bridge->owner = THIS_MODULE; > + > /* Setup IRQ */ > retval = ca91cx42_irq_init(ca91cx42_bridge); > if (retval != 0) { > diff --git a/drivers/staging/vme/bridges/vme_tsi148.c b/drivers/staging/vme/bridges/vme_tsi148.c > index 5c147d6..9db89dc 100644 > --- a/drivers/staging/vme/bridges/vme_tsi148.c > +++ b/drivers/staging/vme/bridges/vme_tsi148.c > @@ -2320,6 +2320,8 @@ static int tsi148_probe(struct pci_dev *pdev, const struct pci_device_id *id) > tsi148_bridge->parent = &pdev->dev; > strcpy(tsi148_bridge->name, driver_name); > > + tsi148_bridge->owner = THIS_MODULE; > + > /* Setup IRQ */ > retval = tsi148_irq_init(tsi148_bridge); > if (retval != 0) { > diff --git a/drivers/staging/vme/vme.c b/drivers/staging/vme/vme.c > index f811d07..0504007 100644 > --- a/drivers/staging/vme/vme.c > +++ b/drivers/staging/vme/vme.c > @@ -52,6 +52,54 @@ static struct vme_bridge *dev_to_bridge(struct device *dev) > } > > /* > + * Increments the reference count of a VME bridge. > + * > + * If found, a pointer to the bridge is returned and the reference count > + * of the module that owns it is incremented. > + * > + * On success, it can be assumed that the bridge won't be removed until > + * the corresponding call to vme_put_bridge(). > + * > + * Normally drivers should call vme_get_bridge() on a successfull .probe, > + * and vme_put_bridge() when releasing the device, e.g. in .remove. > + */ > +struct vme_bridge *vme_bridge_get(unsigned int bus_id) > +{ > + struct vme_bridge *bridge; > + struct vme_bridge *retp = NULL; > + > + mutex_lock(&vme_buses_lock); > + list_for_each_entry(bridge, &vme_bus_list, bus_list) { > + if (bridge->num == bus_id) { > + if (!bridge->owner) > + dev_warn(bridge->parent, > + "bridge->owner not set\n"); > + else if (try_module_get(bridge->owner)) > + retp = bridge; > + break; > + } > + } > + mutex_unlock(&vme_buses_lock); > + return retp; > +} > +EXPORT_SYMBOL(vme_bridge_get); > + > +/* > + * Decrements the reference count of a bridge > + * > + * This function decrements the reference count of the module that controls > + * the bridge. It must come after a call to vme_get_bridge(). > + */ > +void vme_bridge_put(struct vme_bridge *bridge) > +{ > + if (!bridge->owner) > + dev_warn(bridge->parent, "bridge->owner not set\n"); > + else > + module_put(bridge->owner); > +} > +EXPORT_SYMBOL(vme_bridge_put); > + > +/* > * Find the bridge that the resource is associated with. > */ > static struct vme_bridge *find_bridge(struct vme_resource *resource) > @@ -1525,9 +1573,13 @@ static int vme_bus_probe(struct device *dev) > driver = dev_to_vme_driver(dev); > bridge = dev_to_bridge(dev); > > + vme_bridge_get(bridge->num); > if (driver->probe != NULL) > retval = driver->probe(dev, bridge->num, vme_calc_slot(dev)); > > + if (retval) > + vme_bridge_put(bridge); > + > return retval; > } > > @@ -1543,6 +1595,8 @@ static int vme_bus_remove(struct device *dev) > if (driver->remove != NULL) > retval = driver->remove(dev, bridge->num, vme_calc_slot(dev)); > > + vme_bridge_put(bridge); > + > return retval; > } > > diff --git a/drivers/staging/vme/vme.h b/drivers/staging/vme/vme.h > index 3ccb497..8fb35e2 100644 > --- a/drivers/staging/vme/vme.h > +++ b/drivers/staging/vme/vme.h > @@ -167,6 +167,8 @@ int vme_slot_get(struct device *); > int vme_register_driver(struct vme_driver *); > void vme_unregister_driver(struct vme_driver *); > > +struct vme_bridge *vme_bridge_get(unsigned int bus_id); > +void vme_bridge_put(struct vme_bridge *bridge); > Given that we are recounting automatically in probe and remove, under what circumstances would we need to call them separately? Martyn > #endif /* _VME_H_ */ > > diff --git a/drivers/staging/vme/vme_bridge.h b/drivers/staging/vme/vme_bridge.h > index 8959670..ef751a4 100644 > --- a/drivers/staging/vme/vme_bridge.h > +++ b/drivers/staging/vme/vme_bridge.h > @@ -113,6 +113,7 @@ struct vme_bridge { > struct device *parent; /* Parent device (eg. pdev->dev for PCI) */ > void *driver_priv; /* Private pointer for the bridge driver */ > struct list_head bus_list; /* list of VME buses */ > + struct module *owner; /* module that owns the bridge */ > > struct device dev[VME_SLOTS_MAX]; /* Device registered with > * device model on VME bus -- Martyn Welch (Principal Software Engineer) | Registered in England and GE Intelligent Platforms | Wales (3828642) at 100 T +44(0)127322748 | Barbirolli Square, Manchester, E martyn.welch@xxxxxx | M2 3AB VAT:GB 927559189 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
