kstat_create(9F) Kernel Functions for Drivers kstat_create(9F)
NAME
kstat_create - create and initialize a new kstat
SYNOPSIS
#include <sys/types.h>
#include <sys/kstat.h>
kstat_t *kstat_create(const char *ks_module, int ks_instance,
const char *ks_name, const char *ks_class, uchar_t ks_type,
ulong_t ks_ndata, uchar_t ks_flag);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI)
PARAMETERS
ks_module The name of the provider's module (such as "sd", "esp", ...). The "core" kernel uses the name "unix".
ks_instance The provider's instance number, as from ddi_get_instance(9F). Modules which do not have a meaningful instance number should
use 0.
ks_name A pointer to a string that uniquely identifies this structure. Only KSTAT_STRLEN - 1 characters are significant.
ks_class The general class that this kstat belongs to. The following classes are currently in use: disk, tape, net, controller, vm,
kvm, hat, streams, kstat, and misc.
ks_type The type of kstat to allocate. Valid types are:
KSTAT_TYPE_NAMED Allows more than one data record per kstat.
KSTAT_TYPE_INTR Interrupt; only one data record per kstat.
KSTAT_TYPE_IO I/O; only one data record per kstat
ks_ndata The number of type-specific data records to allocate.
ks_flag A bit-field of various flags for this kstat. ks_flag is some combination of:
KSTAT_FLAG_VIRTUAL Tells kstat_create() not to allocate memory for the kstat data section; instead, the driver will
set the ks_data field to point to the data it wishes to export. This provides a convenient way to
export existing data structures.
KSTAT_FLAG_WRITABLE Makes the kstat data section writable by root.
KSTAT_FLAG_PERSISTENT Indicates that this kstat is to be persistent over time. For persistent kstats, kstat_delete(9F)
simply marks the kstat as dormant; a subsequent kstat_create() reactivates the kstat. This feature
is provided so that statistics are not lost across driver close/open (such as raw disk I/O on a
disk with no mounted partitions.) Note: Persistent kstats cannot be virtual, since ks_data points
to garbage as soon as the driver goes away.
DESCRIPTION
kstat_create() is used in conjunction with kstat_install(9F) to allocate and initialize a kstat(9S) structure. The method is generally as
follows:
kstat_create() allocates and performs necessary system initialization of a kstat(9S) structure. kstat_create() allocates memory for the
entire kstat (header plus data), initializes all header fields, initializes the data section to all zeroes, assigns a unique kstat ID
(KID), and puts the kstat onto the system's kstat chain. The returned kstat is marked invalid because the provider (caller) has not yet had
a chance to initialize the data section.
After a successful call to kstat_create() the driver must perform any necessary initialization of the data section (such as setting the
name fields in a kstat of type KSTAT_TYPE_NAMED). Virtual kstats must have the ks_data field set at this time. The provider may also set
the ks_update, ks_private, and ks_lock fields if necessary.
Once the kstat is completely initialized, kstat_install(9F) is used to make the kstat accessible to the outside world.
RETURN VALUES
If successful, kstat_create() returns a pointer to the allocated kstat. NULL is returned upon failure.
CONTEXT
kstat_create() can be called from user or kernel context.
EXAMPLES
Example 1 Allocating and Initializing a kstat Structure
pkstat_t *ksp;
ksp = kstat_create(module, instance, name, class, type, ndata, flags);
if (ksp) {
/* ... provider initialization, if necessary */
kstat_install(ksp);
}
SEE ALSO
kstat(3KSTAT), ddi_get_instance(9F), kstat_delete(9F), kstat_install(9F), kstat_named_init(9F), kstat(9S), kstat_named(9S)
Writing Device Drivers
SunOS 5.11 13 Nov 2006 kstat_create(9F)