scsi_pktfree(9F)
NAME
scsi_pktalloc, scsi_resalloc, scsi_pktfree, scsi_resfree -
SCSI packet utility routines
SYNOPSIS
#include <sys/scsi/scsi.h>
struct scsi_pkt *scsi_pktalloc(struct scsi_address*ap,
intcmdlen, intstatuslen, int(*callback )(void));
struct scsi_pkt *scsi_resalloc(struct scsi_address*ap,
intcmdlen, intstatuslen, opaque_tdmatoken, int(*callback
)(void));
voidscsi_pktfree(struct scsi_pkt*pkt);
voidscsi_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and scsi_resalloc() functions have been replaced by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functions have been replaced by scsi_destroy_pkt(9F).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 completion
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
scsi_pktalloc() 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.
cmdlen is the required length for the SCSI command descrip-
tor block. This block is allocated such that a kernel vir-
tual 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.
dmatoken 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 dmato-
ken is NULL, no DMA resources are required by this SCSI com-
mand, 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 infor-
mation 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 available. call-
back must return either 0 (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 1 indicating either
success in allocating resources or indicating
that it no longer cares for a retry.
scsi_pktfree() frees the packet.
scsi_resfree() 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 may only be
called from user-level code. Otherwise, it may be called
from either user or interrupt level. The callback function
may not block or call routines that block. Both deallocation
routines can be called from user 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).
Man(1) output converted with
man2html