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scsi_sync_pkt - synchronize CPU and I/O views of memory

#include <sys/scsi/scsi.h>



void scsi_sync_pkt(struct scsi_pkt *pktp);

illumos DDI specific (illumos DDI). pktp The scsi_sync_pkt() function is used to selectively synchronize a CPU's or device's view of the data associated with the SCSI packet that has been mapped for I/O. This may involve operations such as flushes of CPU or I/O caches, as well as other more complex operations such as stalling until hardware write buffers have drained.

This function need only be called under certain circumstances. When a SCSI packet is mapped for I/O using scsi_init_pkt(9F) and destroyed using scsi_destroy_pkt(9F), then an implicit scsi_sync_pkt() will be performed. However, if the memory object has been modified by either the device or a CPU after the mapping by scsi_init_pkt(9F), then a call to scsi_sync_pkt() is required.

If the same scsi_pkt is reused for a data transfer from memory to a device, then scsi_sync_pkt() must be called before calling scsi_transport(9F). If the same packet is reused for a data transfer from a device to memory scsi_sync_pkt() must be called after the completion of the packet but before accessing the data in memory.

The scsi_sync_pkt() function may be called from user, interrupt, or kernel context. tran_sync_pkt (9E), ddi_dma_sync (9F), scsi_destroy_pkt (9F), scsi_init_pkt (9F), scsi_transport (9F), scsi_pkt (9S)

Writing Device Drivers