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 Reserved 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. See ddi_iopb_alloc(9F) and ddi_dma_sync(9F) for more details. 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.

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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