getrbuf(9F)

NAME

     getrbuf - get a raw buffer header

SYNOPSIS

     #include <sys/buf.h>
     #include <sys/kmem.h>
     #include <sys/ddi.h>

     struct buf *getrbuf(int sleepflag);

INTERFACE LEVEL

     Architecture independent level 1 (DDI/DKI).

PARAMETERS

     sleepflag
           Indicates whether driver should sleep for free space.

DESCRIPTION

     getrbuf() allocates the space for a  buffer  header  to  the
     caller.   It  is  used in cases where a block driver is per-
     forming raw (character interface) I/O and needs to set up  a
     buffer header that is not associated with the buffer cache.

     getrbuf() calls  kmem_alloc(9F) to perform the memory  allo-
     cation.
       kmem_alloc()requires  the  information  included  in   the
     sleepflag  argument.   If  sleepflag is set to KM_SLEEP, the
     driver may sleep until the space is freed up.  If  sleepflag
     is  set  to    KM_NOSLEEP,  the  driver  will not sleep.  In
     either case, a pointer to the allocated space is returned or
     NULL to indicate that no space was available.

RETURN VALUES

     getrbuf() returns a pointer to the allocated buffer  header,
     or  NULL if no space is available.

CONTEXT

     getrbuf() can be called  from  user  or  interrupt  context.
     (Drivers must not allow getrbuf() to sleep if called from an
     interrupt routine.)

SEE ALSO

     bioinit(9F), freerbuf(9F), kmem_alloc(9F), kmem_free(9F)

     Writing Device Drivers