scsi_alloc_consistent_buf(9F)

NAME

scsi_alloc_consistent_buf − allocate an I/O buffer for SCSI DMA

SYNOPSIS

#include <sys/scsi/scsi.h>

struct buf ∗scsi_alloc_consistent_buf(struct scsi_address ∗ap, struct buf ∗bp,

int datalen, ulong bflags, int (∗callback )(caddr_t) , caddr_t arg);

ARGUMENTS

ap Pointer to the scsi_address structure.

bp Pointer to the buf(9S) structure.

datalen Number of bytes for the data buffer.

bflags Flags setting for the allocated buffer header.

callback NULL_FUNC or SLEEP_FUNC.

arg callback function argument, must be set to NULL.

INTERFACE LEVEL

Solaris architecture specific (SunDDI).

DESCRIPTION

scsi_alloc_consistent_buf() allocates a buffer header and the associated data buffer for direct memory access (DMA) transfer. This buffer is allocated from the iobp space, which is considered consistent memory. For more details, see ddi_iopb_alloc(9F) and ddi_dma_sync(9F).

If bp is NULL, a new buffer header will be allocated using getrbuf(9F). In addition, if datalen is non-zero, a new buffer will be allocated using ddi_iopb_alloc(9F).

callback indicates what the allocator routines should do when direct memory access (DMA) resources are not available; the valid values are:

NULL_FUNC Do not wait for resources. Return a NULL pointer.

SLEEP_FUNC
Wait indefinitely for resources.

RETURN VALUES

scsi_alloc_consistent_buf() returns a pointer to a buf(9S) structure 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-level code. Otherwise, it may be called from either user or interrupt level. The callback function may not block or call routines that block.

EXAMPLE

    bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
         SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL);
    rqpkt = scsi_init_pkt(&devp->sd_address,
         NULL, bp, CDB_GROUP0, 1, 0,
         PKT_CONSISTENT, SLEEP_FUNC, NULL);

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