scsi_pktalloc(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, int cmdlen, int statuslen,

int (∗callback)(void));

struct scsi_pkt ∗scsi_resalloc(struct scsi_address ∗ap, int cmdlen, int statuslen,

opaque_t dmatoken, int (∗callback)(void));

void scsi_pktfree(struct scsi_pkt ∗pkt);

void scsi_resfree(struct scsi_pkt ∗pkt);

ARGUMENTS

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.

INTERFACE LEVEL

SPARC architecture specific (SPARC DDI).

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 routines use it to determine the associated host adapter.

cmdlen is the required length for the SCSI command descriptor block. This block is allocated such that a kernel virtual address is established in the pkt_cdbp field of the allocated scsi_pkt structure.

statuslen is the required length for the SCSI status completion block. This block is allocated such that a kernel virtual address is established in the pkt_scbp field of the allocated 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 dmatoken is NULL , no DMA resources are required by this SCSI 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 pkt_reason set to CMD_DMA_DERR. dmatoken provides the information to determine if the transfer count is correct.

callback indicates what the allocator routines should do when DMA 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 become available. callback must return either 0 (indicating that it attempted to allocate a DMA mapping 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 DMA 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

Both allocation routines can be called from user or interrupt context except when callback is set to a value other than NULL_FUNC, in which case they can be called from user context only.

Both deallocation routines can be called from user or interrupt context.

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