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

ldi_ev_notify - propagate notification of a state change event

#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);

illumos DDI specific (illumos DDI)

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.

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

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

Theldi_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);
}

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.

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

ldi_ev_get_cookie(9F), ldi_ev_register_callbacks(9F), ldi_ev_remove_callbacks(9F)

August 21, 2007 OmniOS