SLEEP_ALLOC(D3DK) —

NAME

SLEEP_ALLOC − allocate and initialize a sleep lock .IX \f4SLEEP_ALLOC\fP(D3DK)

SYNOPSIS

#include <sys/types.h>
#include <sys/kmem.h>
#include <sys/ksynch.h>
sleep_t ∗SLEEP_ALLOC(int arg, lkinfo_t ∗lkinfop, int flag);

ARGUMENTS

argPlaceholder for future use. arg must be equal to zero.

lkinfopPointer to a lkinfo(D4DK) structure. The lk_name member of the lkinfo structure points to a character string defining a name that will be associated with the lock for the purpose of statistics gathering. The name should begin with the driver prefix and should be unique to the lock or group of locks for which the driver wishes to collect a uniquely identifiable set of statistics (i.e. if a given name is shared by a group of locks, the statistics of individual locks within the group will not be uniquely identifiable). The only bit flag currently specified within the lk_flags member of the lkinfo structure is the LK_NOSTATS flag, which specifies that statistics are not to be collected for this particular lock under the _MPSTATS compilation option. If the LK_NOSTATS flag is not specified, statistics will be collected for this lock under the _MPSTATS compilation option, and the lkinfop pointer will be recorded in the statistics buffer along with the lock statistics. A given lkinfo structure may be shared among multiple sleep locks but a lkinfo structure may not be shared between a sleep lock and a basic or read/write lock. The caller must ensure that the lk_pad member of the lkinfo structure is zeroed out before passing it to SLEEP_ALLOC.

flagSpecifies whether the caller is willing to sleep waiting for memory. If flag is set to KM_SLEEP, the caller will sleep if necessary until sufficient memory is available. If flag is set to KM_NOSLEEP, the caller will not sleep, but SLEEP_ALLOC will return NULL if sufficient memory is not immediately available. Under the _MPSTATS compilation option, if KM_NOSLEEP is specified and sufficient memory can be immediately allocated for the lock itself but not for an accompanying statistics buffer, SLEEP_ALLOC will return a pointer to the allocated lock but individual statistics will not be collected for the lock.

DESCRIPTION

SLEEP_ALLOC dynamically allocates and initializes an instance of a sleep lock. The lock is initialized to the unlocked state.

RETURN VALUE

Upon successful completion, SLEEP_ALLOC returns a pointer to the newly allocated lock. If KM_NOSLEEP is specified and sufficient memory is not immediately available, SLEEP_ALLOC returns a NULL pointer.

LEVEL

Base only if flag is set to KM_SLEEP. Base or interrupt if flag is set to KM_NOSLEEP.

NOTES

May sleep if flag is set to KM_SLEEP. Driver defined basic locks and read/write locks may be held across calls to this function if flag is KM_NOSLEEP but may not be held if flag is KM_SLEEP. Driver defined sleep locks may be held across calls to this function regardless of the value of flag.

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