'\" te
.\" Copyright (c) 2006, Sun Microsystems, Inc.,
.\" All Rights Reserved
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.TH SCSI_PKTALLOC 9F "Jan 16, 2006"
.SH NAME
scsi_pktalloc, scsi_resalloc, scsi_pktfree, scsi_resfree \- SCSI packet utility
routines
.SH SYNOPSIS
.LP
.nf
#include <sys/scsi/scsi.h>

\fBstruct scsi_pkt *\fR\fBscsi_pktalloc\fR (\fBstruct scsi_address*\fR \fIap\fR, \fBint\fR \fIcmdlen\fR,
     \fBint\fR \fIstatuslen\fR, \fBint\fR (\fI*callback\fR)(\fIvoid\fR));
.fi

.LP
.nf
\fBstruct scsi_pkt *\fR\fBscsi_resalloc\fR (\fBstruct scsi_address*\fR \fIap\fR, \fBint\fR \fIcmdlen\fR,
     \fBint\fR \fIstatuslen\fR, \fBopaque_t\fR \fIdmatoken\fR, \fBint\fR (\fI*callback\fR)(\fIvoid\fR));
.fi

.LP
.nf
\fBvoid\fR \fBscsi_pktfree\fR (\fBstruct scsi_pkt*\fR \fIpkt\fR);
.fi

.LP
.nf
\fBvoid\fR \fBscsi_resfree\fR (\fBstruct scsi_pkt*\fR \fIpkt\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
The \fBscsi_pktalloc()\fR, \fBscsi_pktfree()\fR, \fBscsi_resalloc()\fR, and
\fBscsi_resfree()\fR functions are obsolete. The \fBscsi_pktalloc()\fR and
\fBscsi_resalloc()\fR functions have been replaced by \fBscsi_init_pkt\fR(9F).
The \fBscsi_pktfree()\fR and \fBscsi_resfree()\fR functions have been replaced
by \fBscsi_destroy_pkt\fR(9F).
.SH PARAMETERS
.sp
.ne 2
.na
\fB\fIap\fR\fR
.ad
.RS 13n
Pointer to a \fBscsi_address\fR structure.
.RE

.sp
.ne 2
.na
\fB\fIcmdlen\fR\fR
.ad
.RS 13n
The required length for the \fBSCSI \fRcommand descriptor block (\fBCDB\fR) in
bytes.
.RE

.sp
.ne 2
.na
\fB\fIstatuslen\fR\fR
.ad
.RS 13n
The required length for the \fBSCSI\fR status completion block (\fBSCB\fR) in
bytes.
.RE

.sp
.ne 2
.na
\fB\fIdmatoken\fR\fR
.ad
.RS 13n
Pointer to an implementation-dependent object.
.RE

.sp
.ne 2
.na
\fB\fIcallback\fR\fR
.ad
.RS 13n
A pointer to a callback function, or \fBNULL_FUNC\fR or \fBSLEEP_FUNC\fR.
.RE

.sp
.ne 2
.na
\fB\fIpkt\fR\fR
.ad
.RS 13n
Pointer to a \fBscsi_pkt\fR(9S) structure.
.RE

.SH DESCRIPTION
.sp
.LP
The \fBscsi_pktalloc()\fR function requests the host adapter driver to allocate
a command packet. For commands that have a data transfer associated with them,
\fBscsi_resalloc()\fR should be used.
.sp
.LP
\fIap\fR is a pointer to a \fBscsi_address\fR structure. Allocator routines use
it to determine the associated host adapter.
.sp
.LP
The \fIcmdlen\fR parameter is the required length for the \fBSCSI \fRcommand
descriptor block. This block is allocated such that a kernel virtual address is
established in the \fBpkt_cdbp\fR field of the allocated \fBscsi_pkt\fR
structure.
.sp
.LP
\fIstatuslen\fR is the required length for the \fBSCSI \fRstatus completion
block. The address of the allocated block is placed into the \fBpkt_scbp\fR
field of the \fBscsi_pkt\fR structure.
.sp
.LP
The \fIdmatoken\fR parameter is a pointer to an implementation dependent object
which defines the length, direction, and address of the data transfer
associated with this \fBSCSI\fR packet (command). The \fIdmatoken\fR must be a
pointer to a \fBbuf\fR(9S) structure. If \fIdmatoken\fR is \fINULL\fR, no
\fBDMA\fR resources are required by this \fBSCSI\fR 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
\fBpkt_reason\fR set to \fBCMD_DMA_DERR\fR. \fIdmatoken\fR provides the
information to determine if the transfer count is correct.
.sp
.LP
\fIcallback\fR indicates what the allocator routines should do when resources
are not available:
.sp
.ne 2
.na
\fB\fBNULL_FUNC\fR\fR
.ad
.RS 16n
Do not wait for resources. Return a \fINULL\fR pointer.
.RE

.sp
.ne 2
.na
\fB\fBSLEEP_FUNC\fR\fR
.ad
.RS 16n
Wait indefinitely for resources.
.RE

.sp
.ne 2
.na
\fBOther Values\fR
.ad
.RS 16n
\fIcallback\fR points to a function which is called when resources may have
become available. \fIcallback\fR must return either \fB0\fR (indicating 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 \fB1\fR indicating either
success in allocating resources or indicating that it no longer cares for a
retry.
.RE

.sp
.LP
The \fBscsi_pktfree()\fR function frees the packet.
.sp
.LP
The \fBscsi_resfree()\fR function free all resources held by the packet and the
packet itself.
.SH RETURN VALUES
.sp
.LP
Both allocation routines return a pointer to a \fBscsi_pkt\fR structure on
success, or \fINULL\fR on failure.
.SH CONTEXT
.sp
.LP
If \fIcallback\fR is \fBSLEEP_FUNC\fR, then this routine can be called only
from user or kernel context. Otherwise, it can be called from user, kernel, or
interrupt context. The \fIcallback\fR function may not block or call routines
that block. Both deallocation routines can be called from user, kernel, or
interrupt context.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for a description of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Stability Level	Obsolete
.TE

.SH SEE ALSO
.sp
.LP
.BR attributes (7),
.BR scsi_dmafree (9F),
.BR scsi_dmaget (9F),
.BR buf (9S),
.BR scsi_pkt (9S)
.sp
.LP
\fIWriting Device Drivers\fR
.SH NOTES
.sp
.LP
The \fBscsi_pktalloc()\fR, \fBscsi_pktfree()\fR, \fBscsi_resalloc()\fR, and
\fBscsi_resfree()\fR functions are obsolete and will be discontinued in a
future release. The \fBscsi_pktalloc()\fR and \fBscsi_resalloc()\fR functions
have been replaced by \fBscsi_init_pkt\fR(9F). The \fBscsi_pktfree()\fR and
\fBscsi_resfree()\fR functions have been replaced by
\fBscsi_destroy_pkt\fR(9F).