Tribblix: manual page: ldi_ev

LDI_EV_NOTIFY(9F) Kernel Functions for Drivers LDI_EV_NOTIFY(9F)

NAME

ldi_ev_notify - propagate notification of a state change event

SYNOPSIS

#include <sys/sunldi.h>

int ldi_ev_notify(dev_info_t *dip, minor_t minor, int spec_type,
ldi_ev_cookie_t cookie, void *ev_data);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

dev_info_t *dip

The devinfo node of the layered consumer exporting the minor
device.

minor_t minor

The minor number of the exported minor device.

int spec_type

The type of minor device (S_IFCHR or S_IFBLK).

ldi_ev_cookie_t cookie

An opaque event cookie for the event type returned by a previous
call to ldi_ev_get_cookie(9F).

void *ev_data

Event specific data.

DESCRIPTION

The ldi_ev_notify() function propagates an event up the software
stack. It may result in two actions:

o Invocation of LDI callback handlers registered by layered
drivers up the software stack.

o Device contract events generated on minors exported to
userland.

The event propagated up the software stack may be different than the
event received by the layered driver invoking ldi_ev_notify(). For
example, a volume manager may receive an "offline" event on one of
it's LDI opened disks, but may choose to propagate a "degraded" event
on minors it exports to userland (since it may have more than one
copy of the data). The event cookie argument to ldi_ev_notify() may
be different from the event cookie currently possessed by the layered
driver. If that is the case, the layered driver must generate another
event cookie via a new ldi_ev_get_cookie(9F) call.

The ldi_ev_* interfaces are designed to ensure that a "finalize" call
is generated for layered driver consumers at the earliest point where
an LDI_EV_FAILURE is detected. If this happens inside the LDI event
framework, then the framework will invoke finalize. In the event a
layered driver detects/generates an LDI_EV_FAILURE, then the layered
driver must invoke ldi_ev_finalize(). The following is an example of
a layered driver invoking ldi_ev_finalize() for the "foo" event:

static int
widget_notify(ldi_handle_t lh, ldi_ev_cookie_t foo_cookie, void *arg,
void *ev_data)
{

ASSERT(strcmp(ldi_ev_get_type(foo_cookie), LDI_EV_FOO) == 0);

/* Map imported minors to exported minor */
widget_map(lh, &minor, &spec_type);

/*
* Call ldi_ev_notify() to propagate events to our consumers.
* This *must* happen before we check if widget should block
* foo
*/
if (ldi_ev_notify(dip, minor, spec_type, foo_cookie, ev_data)
!= LDI_EV_SUCCESS)
return (LDI_EV_FAILURE);

/*
* Next, check if we can allow the foo event
*/
if (widget_release(lh, LDI_EV_FOO) == WIDGET_SUCCESS) {
return (LDI_EV_SUCCESS)
}

/*
* We cannot permit the foo event. The first layer that detects
* failure i.e. us, must generate finalize events for *our*
* consumers
*/
ldi_ev_finalize(dip, minor, spec_type, LDI_EV_FAILURE,
foo_cookie, ev_data);

return (LDI_EV_FAILURE);
}

RETURN VALUES

The return values for this function are:

LDI_EV_SUCCESS

Consumers up the software stack permit state change.

LDI_EV_FAILURE

Consumers are blocking the state change.

CONTEXT

This function can be called from user and kernel context only.