Manual Pages for UNIX Operating System command usage for man scsi_pktfree

Kernel Functions for Drivers                    scsi_pktalloc(9F)



NAME
     scsi_pktalloc, scsi_resalloc, scsi_pktfree,  scsi_resfree  -
     SCSI packet utility routines

SYNOPSIS
     #include 

     struct scsi_pkt *scsi_pktalloc (struct scsi_address* ap, int cmdlen,
          int statuslen, int (*callback)(void));


     struct scsi_pkt *scsi_resalloc (struct scsi_address* ap, int cmdlen,
          int statuslen, opaque_t dmatoken, int (*callback)(void));


     void scsi_pktfree (struct scsi_pkt* pkt);


     void scsi_resfree (struct scsi_pkt* pkt);


INTERFACE LEVEL
     The scsi_pktalloc(),  scsi_pktfree(),  scsi_resalloc(),  and
     scsi_resfree()  functions  are obsolete. The scsi_pktalloc()
     and  scsi_resalloc()  functions  have   been   replaced   by
     scsi_init_pkt(9F).  The  scsi_pktfree()  and  scsi_resfree()
     functions have been replaced by scsi_destroy_pkt(9F).

PARAMETERS
     ap           Pointer to a scsi_address structure.


     cmdlen       The  required  length  for  the  SCSI   command
                  descriptor block (CDB) in bytes.


     statuslen    The required length for the SCSI status comple-
                  tion block (SCB) in bytes.


     dmatoken     Pointer to an implementation-dependent object.


     callback     A pointer to a callback function, or  NULL_FUNC
                  or SLEEP_FUNC.


     pkt          Pointer to a scsi_pkt(9S) structure.


DESCRIPTION




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Kernel Functions for Drivers                    scsi_pktalloc(9F)



     The  scsi_pktalloc()  function  requests  the  host  adapter
     driver  to allocate a command packet. For commands that have
     a data transfer associated with them, scsi_resalloc() should
     be used.


     ap is a pointer to a scsi_address structure. Allocator  rou-
     tines use it to determine the associated host adapter.


     The cmdlen parameter is the required  length  for  the  SCSI
     command  descriptor block. This block is allocated such that
     a kernel virtual address  is  established  in  the  pkt_cdbp
     field of the allocated scsi_pkt structure.


     statuslen is the required length for the SCSI status comple-
     tion  block.  The  address  of the allocated block is placed
     into the pkt_scbp field of the scsi_pkt structure.


     The dmatoken parameter is a  pointer  to  an  implementation
     dependent  object  which  defines the length, direction, and
     address of the  data  transfer  associated  with  this  SCSI
     packet  (command).  The  dmatoken  must  be  a  pointer to a
     buf(9S) structure. If dmatoken is NULL, no DMA resources are
     required  by  this SCSI command, so none are allocated. Only
     one transfer direction is allowed per command. If  there  is
     an  unexpected  data transfer phase (either no data transfer
     phase expected, or the  wrong  direction  encountered),  the
     command   is   terminated   with   the   pkt_reason  set  to
     CMD_DMA_DERR. dmatoken provides the information to determine
     if the transfer count is correct.


     callback indicates what the  allocator  routines  should  do
     when resources are not available:

     NULL_FUNC       Do not wait for  resources.  Return  a  NULL
                     pointer.


     SLEEP_FUNC      Wait indefinitely for resources.


     Other Values    callback  points  to  a  function  which  is
                     called when resources may have become avail-
                     able. callback must return either  0  (indi-
                     cating   that   it   attempted  to  allocate
                     resources but again failed  to  do  so),  in
                     which  case  it  is put back on a list to be
                     called again later, or 1  indicating  either



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Kernel Functions for Drivers                    scsi_pktalloc(9F)



                     success  in allocating resources or indicat-
                     ing that it no longer cares for a retry.



     The scsi_pktfree() function frees the packet.


     The scsi_resfree() function free all resources held  by  the
     packet and the packet itself.

RETURN VALUES
     Both allocation routines return  a  pointer  to  a  scsi_pkt
     structure on success, or NULL on failure.

CONTEXT
     If callback is SLEEP_FUNC, then this routine can  be  called
     only  from  user  or  kernel  context.  Otherwise, it can be
     called from user, kernel, or interrupt context. The callback
     function  may  not  block  or call routines that block. Both
     deallocation routines can be called from  user,  kernel,  or
     interrupt context.

ATTRIBUTES
     See attributes(5) for a description of the following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Stability Level             | Obsolete                    |
    |_____________________________|_____________________________|


SEE ALSO
     attributes(5), scsi_dmafree(9F),  scsi_dmaget(9F),  buf(9S),
     scsi_pkt(9S)


     Writing Device Drivers

NOTES
     The scsi_pktalloc(),  scsi_pktfree(),  scsi_resalloc(),  and
     scsi_resfree() functions are obsolete and will be discontin-
     ued  in  a   future   release.   The   scsi_pktalloc()   and
     scsi_resalloc()    functions    have    been   replaced   by
     scsi_init_pkt(9F).  The  scsi_pktfree()  and  scsi_resfree()
     functions have been replaced by scsi_destroy_pkt(9F).





SunOS 5.11          Last change: 16 Jan 2006                    3