Solaris DDI specific (Solaris DDI).

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.

get_pktiopb() 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.

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

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

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.

free_pktiopb() can be called from user or interrupt context.

ddi_iopb_alloc(9F), scsi_alloc_consistent_buf(9F), scsi_free_consistent_buf(9F), scsi_pktalloc(9F), scsi_resalloc(9F), scsi_pkt(9S)

Writing Device Drivers

get_pktiopb() and free_pktiopb() are old functions and should be replaced with scsi_alloc_consistent_buf(9F) and scsi_free_consistent_buf(9F). get_pktiopb() uses scarce resources. Use it selectively.