scsi_dmaget(9F) Kernel Functions for Drivers scsi_dmaget(9F)NAME
scsi_dmaget, scsi_dmafree - SCSI dma utility routines
SYNOPSIS
#include <sys/scsi/scsi.h>
struct scsi_pkt *scsi_dmaget(struct scsi_pkt *pkt, opaque_t dmatoken,
int(*callback)(void));
void scsi_dmafree(struct scsi_pkt *pkt);
INTERFACE LEVEL
These interfaces are obsolete. Use scsi_init_pkt(9F) instead of
scsi_dmaget(). Use scsi_destroy_pkt(9F) instead of scsi_dmafree().
PARAMETERS
pkt A pointer to a scsi_pkt(9S) structure.
dmatoken Pointer to an implementation dependent object.
callback Pointer to a callback function, or NULL_FUNC or
SLEEP_FUNC.
DESCRIPTION
The scsi_dmaget() function allocates DMA resources for an already allo‐
cated SCSI packet. pkt is a pointer to the previously allocated SCSI
packet (see scsi_pktalloc(9F)).
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 resources
are allocated.
The callback parameter indicates what scsi_dmaget() 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 allo‐
cate 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 scsi_dmafree() function frees the DMA resources associated with the
SCSI packet. The packet itself remains allocated.
RETURN VALUES
The scsi_dmaget() function returns a pointer to a scsi_pkt on success.
It returns NULL if resources are not available.
CONTEXT
If callback is SLEEP_FUNC, then this routine may only be called from
user or kernel context. Otherwise, it may be called from user, kernel,
or interrupt context. The callback function may not block or call rou‐
tines that block.
The scsi_dmafree() function can be called from user, interrupt, or ker‐
nel context.
ATTRIBUTES
See attributes(5) for a description of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Stability Level │Obsolete │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOattributes(5), scsi_pktalloc(9F), scsi_pktfree(9F), scsi_resalloc(9F),
scsi_resfree(9F), buf(9S), scsi_pkt(9S)
Writing Device Drivers
NOTES
The scsi_dmaget() and scsi_dmafree() functions are obsolete and will be
discontinued in a future release. These functions have been replaced
by, respectively, scsi_init_pkt(9F) and scsi_destroy_pkt(9F).
SunOS 5.10 16 Jan 2006 scsi_dmaget(9F)
