KSTAT_CREATE(9F)KSTAT_CREATE(9F)NAMEkstat_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 mean‐
ingful instance number should use 0.
ks_name
A pointer to a string that uniquely identifies this
structure. Only KSTAT_STRLEN − 1 characters are signifi‐
cant.
ks_class
The general class that this kstat belongs to. The fol‐
lowing 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 subse‐
quent kstat_create() reacti‐
vates 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.
DESCRIPTIONkstat_create() is used in conjunction with kstat_install(9F) to allo‐
cate 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, ini‐
tializes 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.
CONTEXTkstat_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 ALSOkstat(3KSTAT), ddi_get_instance(9F), kstat_delete(9F),
kstat_install(9F), kstat_named_init(9F), kstat(9S), kstat_named(9S)
Writing Device Drivers
Nov 13, 2006 KSTAT_CREATE(9F)
