getrbuf(9f) - osol9

1getrbuf(9F)              Kernel Functions for Drivers              getrbuf(9F)
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NAME

6       getrbuf - get a raw buffer header
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SYNOPSIS

9       #include <sys/buf.h>
10       #include <sys/kmem.h>
11       #include <sys/ddi.h>
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15       struct buf *getrbuf(int sleepflag);
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INTERFACE LEVEL

19       Architecture independent level 1 (DDI/DKI).
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PARAMETERS

22       sleepflag    Indicates whether driver should sleep for free space.
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DESCRIPTION

26       The  getrbuf()  function allocates the space for a buffer header to the
27       caller. It is used in cases where a  block  driver  is  performing  raw
28       (character  interface)  I/O and needs to set up a buffer header that is
29       not associated with the buffer cache.
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32       The getrbuf() function calls kmem_alloc(9F) to perform the memory allo‐
33       cation.  kmem_alloc()requires the information included in the sleepflag
34       argument. If sleepflag is set to KM_SLEEP, the driver may  sleep  until
35       the  space  is  freed up. If sleepflag is set to KM_NOSLEEP, the driver
36       will not sleep.  In either case, a pointer to the  allocated  space  is
37       returned or NULL to indicate that no space was available.
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RETURN VALUES

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

44       The getrbuf() function can be called from user,  interrupt,  or  kernel
45       context.  (Drivers  must not allow getrbuf() to sleep if called from an
46       interrupt routine.)
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