man pages section 9: DDI and DKI Kernel Functions

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Updated: July 2014
 
 

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

Solaris DDI specific (Solaris 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:

  • 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);
}

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.

See Also

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