| MC_GETSTAT(9E) | Driver Entry Points | MC_GETSTAT(9E) |
mc_getstat — get
device statistics information
#include
<sys/mac_provider.h>
#include <sys/mac_ether.h>
int
prefix_m_getstat(void *driver,
uint_t stat, uint64_t
*stat_value);
illumos DDI specific
The
mc_getstat()
entry point is used to get statistics from the device driver. Statistics are
stored as monotonic values. They should only ever increase over the lifetime
of a device, resetting only as part of the instance of a device attaching
and detaching. When hardware has values that may overflow, it is up to the
device driver to store them as a 64-bit quantity that does not overflow in
its soft state.
Most device drivers will use a switch statement, switching on the value of the statistic stat. The full list of supported statistics is available in the STATISTICS section of mac(9E).
If a device driver recognizes the value of
stat, then it should store the current 64-bit unsigned
integer into stat_value. If the device driver does not
support the statistic or does not recognize the requested statistic, then it
should not set anything in stat_value and instead
return ENOTSUP.
The device driver can obtain access to its soft state through the driver member. It should be cast to the appropriate structure. The device driver should employ any necessary locking to access the statistic members of its soft state to ensure that the data is properly serialized.
Upon successful completion, the device driver should fill in stat_value and return 0. Otherwise it should return a non-zero error number to indicate an error occurred.
The following example shows how a driver might structure its
mc_getstat() entry point.
#include <sys/mac_provider.h>
#include <sys/mac_ether.h>
/*
* Note, this example merely shows the structure of the function. For
* the purpose of this example, we assume that we have a device which
* has members that indicate its stats and that it has a lock which is
* used to serialize access to this data.
*/
static int
example_m_getstat(void *arg, uint_t stat, uint64_t *val)
{
example_t *ep = arg;
mutex_enter(&ep->ep_lock);
switch (stat) {
case MAC_STAT_RBYTES:
*val = ep->ep_stats.eps_rbytes;
break;
case MAC_STAT_OBYTES:
*val = ep->ep_stats.eps_obytes;
break;
case MAC_STAT_IPACKETS:
*val = ep->ep_stats.eps_ipackets;
break;
case MAC_STAT_OPACKETS:
*val = ep->ep_stats.eps_opackets;
break;
/*
* Note, there are many more stats that should be checked and
* filled in if supported. You should use one case statement for
* each stat.
*/
default:
mutex_exit(&ep->ep_lock);
return (ENOTSUP);
}
mutex_exit(&ep->ep_lock);
return (0);
}
The device driver may return one of the following errors. While this list is not intended to be exhaustive, it is recommended to use one of these if possible.
ENOTSUPEIOECANCELLED| May 31, 2016 | OmniOS |