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Allow device_busy() and device_unbusy() to be invoked while a device is

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being attached.  This is implemented by adding a new DS_ATTACHING state
while a device's DEVICE_ATTACH() method is being invoked.  A driver is
required to not fail an attach of a busy device.  The device's state will
be promoted to DS_BUSY rather than DS_ACTIVE() if the device was marked
busy during DEVICE_ATTACH().

Reviewed by:	kib
MFC after:	1 week
This commit is contained in:
John Baldwin 2012-04-11 20:57:41 +00:00
parent 805bee55eb
commit 77b479e644
2 changed files with 14 additions and 5 deletions
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18
sys/kern/subr_bus.c
View File

@ -2472,12 +2472,13 @@ device_disable(device_t dev)
void
device_busy(device_t dev)
{
if (dev->state < DS_ATTACHED)
if (dev->state < DS_ATTACHING)
panic("device_busy: called for unattached device");
if (dev->busy == 0 && dev->parent)
device_busy(dev->parent);
dev->busy++;
dev->state = DS_BUSY;
if (dev->state == DS_ATTACHED)
dev->state = DS_BUSY;
}
/**
@ -2486,14 +2487,16 @@ device_busy(device_t dev)
void
device_unbusy(device_t dev)
{
if (dev->state != DS_BUSY)
if (dev->busy != 0 && dev->state != DS_BUSY &&
dev->state != DS_ATTACHING)
panic("device_unbusy: called for non-busy device %s",
device_get_nameunit(dev));
dev->busy--;
if (dev->busy == 0) {
if (dev->parent)
device_unbusy(dev->parent);
dev->state = DS_ATTACHED;
if (dev->state == DS_BUSY)
dev->state = DS_ATTACHED;
}
}
@ -2729,6 +2732,7 @@ device_attach(device_t dev)
device_sysctl_init(dev);
if (!device_is_quiet(dev))
device_print_child(dev->parent, dev);
dev->state = DS_ATTACHING;
if ((error = DEVICE_ATTACH(dev)) != 0) {
printf("device_attach: %s%d attach returned %d\n",
dev->driver->name, dev->unit, error);
@ -2736,11 +2740,15 @@ device_attach(device_t dev)
devclass_delete_device(dev->devclass, dev);
(void)device_set_driver(dev, NULL);
device_sysctl_fini(dev);
KASSERT(dev->busy == 0, ("attach failed but busy"));
dev->state = DS_NOTPRESENT;
return (error);
}
device_sysctl_update(dev);
dev->state = DS_ATTACHED;
if (dev->busy)
dev->state = DS_BUSY;
else
dev->state = DS_ATTACHED;
dev->flags &= ~DF_DONENOMATCH;
devadded(dev);
return (0);

1
sys/sys/bus.h
View File

@ -52,6 +52,7 @@ struct u_businfo {
typedef enum device_state {
DS_NOTPRESENT = 10, /**< @brief not probed or probe failed */
DS_ALIVE = 20, /**< @brief probe succeeded */
DS_ATTACHING = 25, /**< @brief currently attaching */
DS_ATTACHED = 30, /**< @brief attach method called */
DS_BUSY = 40 /**< @brief device is open */
} device_state_t;