GET_PKTIOPB(9F) Kernel Functions for Drivers GET_PKTIOPB(9F)

NAME

get_pktiopb, free_pktiopb - allocate/free a SCSI packet in the iopb
map

SYNOPSIS

#include <sys/scsi/scsi.h>


struct scsi_pkt *get_pktiopb(struct scsi_address *ap,
caddr_t *datap, int cdblen, int statuslen, int datalen,
int readflag, int (*callback);


void free_pktiopb(struct scsi_pkt *pkt, caddr_t datap, int datalen);

INTERFACE LEVEL

These interfaces are obsolete. Use scsi_alloc_consistent_buf(9F)
instead of get_pktiopb(). Use scsi_free_consistent_buf(9F) instead of
free_pktiopb().

PARAMETERS

ap
Pointer to the target's scsi_address structure.


datap
Pointer to the address of the packet, set by this
function.


cdblen
Number of bytes required for the SCSI command descriptor
block (CDB).


statuslen
Number of bytes required for the SCSI status area.


datalen
Number of bytes required for the data area of the SCSI
command.


readflag
If non-zero, data will be transferred from the SCSI
target.


callback
Pointer to a callback function, or NULL_FUNC or
SLEEP_FUNC


pkt
Pointer to a scsi_pkt(9S) structure.

DESCRIPTION

The get_pktiopb() function allocates a scsi_pkt structure that has a
small data area allocated. It is used by some SCSI commands such as
REQUEST_SENSE, which involve a small amount of data and require
cache-consistent memory for proper operation. It uses
ddi_iopb_alloc(9F) for allocating the data area and scsi_resalloc(9F)
to allocate the packet and DMA resources.


callback indicates what get_pktiopb() 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 available. callback must
return either 0 (indicating that it attempted to
allocate resources but failed to do so again), in
which case it is put back on a list to be called
again later, or 1 indicating either success in
allocating resources or indicating that it no longer
cares for a retry.


The free_pktiopb() function is used for freeing the packet and its
associated resources.

RETURN VALUES

The get_pktiopb() function returns a pointer to the newly allocated
scsi_pkt or a NULL pointer.

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,
interrupt, or kernel context. The callback function should not block
or call routines that block.


The free_pktiopb() function can be called from user, interrupt, or
kernel context.

ATTRIBUTES

See attributes(7) for a description of the following attributes:


+----------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------+-----------------+
|Stability Level | Obsolete |
+----------------+-----------------+

SEE ALSO

attributes(7), scsi_alloc_consistent_buf(9F),
scsi_free_consistent_buf(9F), scsi_pktalloc(9F), scsi_resalloc(9F),
scsi_pkt(9S)


Writing Device Drivers

NOTES

The get_pktiopb() and free_pktiopb() functions are obsolete and will
be discontinued in a future release. These functions have been
replaced by, respectively, scsi_alloc_consistent_buf(9F) and
scsi_free_consistent_buf(9F).


The get_pktiopb() function uses scarce resources. For this reason and
its obsolescence (see above), its use is discouraged.

May 24, 2014 GET_PKTIOPB(9F)