int rv;
initialize_hcb_for_data(hcb);
if ((!(ccb_h->flags & CAM_SCATTER_VALID)) {
/* single buffer */
if (!(ccb_h->flags & CAM_DATA_PHYS)) {
rv = add_virtual_chunk(hcb, csio->data_ptr, csio->dxfer_len, dir);
}
} else {
rv = add_physical_chunk(hcb, csio->data_ptr, csio->dxfer_len, dir);
}
} else {
int i;
struct bus_dma_segment *segs;
segs = (struct bus_dma_segment *)csio->data_ptr;
if ((ccb_h->flags & CAM_SG_LIST_PHYS) != 0) {
/* The SG list pointer is physical */
rv = setup_hcb_for_physical_sg_list(hcb, segs, csio->sglist_cnt);
} else if (!(ccb_h->flags & CAM_DATA_PHYS)) {
/* SG buffer pointers are virtual */
for (i = 0; i < csio->sglist_cnt; i++) {
rv = add_virtual_chunk(hcb, segs[i].ds_addr,
segs[i].ds_len, dir);
if (rv != CAM_REQ_CMP)
break;
}
} else {
/* SG buffer pointers are physical */
for (i = 0; i < csio->sglist_cnt; i++) {
rv = add_physical_chunk(hcb, segs[i].ds_addr,
segs[i].ds_len, dir);
if (rv != CAM_REQ_CMP)
break;
}
}
}
if (rv != CAM_REQ_CMP) {
/* we expect that add_*_chunk() functions return CAM_REQ_CMP
* if they added a chunk successfully, CAM_REQ_TOO_BIG if
* the request is too big (too many bytes or too many chunks),
* CAM_REQ_INVALID in case of other troubles
*/
free_hcb_and_ccb_done(hcb, ccb, rv);
return;
}
end_data:
如果为此 CCB 禁用了断开连接，我们将这些信息传递给 hcb:
if (ccb_h->flags & CAM_DIS_DISCONNECT)
hcb_disable_disconnect(hcb);
如果控制器能够独自运行 REQUEST SENSE 命令，那么 CAM_DIS_AUTOSENSE 标志的值也应该传递给它，以防止 CAM 子系统不需要时自动执行 REQUEST SENSE。
int targ, lun;
struct xxx_hcb *h, *hh;
struct ccb_trans_settings neg;
struct cam_path *path;
/* The SCSI bus reset may take a long time, in this case its completion
* should be checked by interrupt or timeout. But for simplicity
* we assume here that it is really fast.
*/
reset_scsi_bus(softc);
/* drop all enqueued CCBs */
for (h = softc->first_queued_hcb; h != NULL; h = hh) {
hh = h->next;
free_hcb_and_ccb_done(h, h->ccb, CAM_SCSI_BUS_RESET);
}
/* the clean values of negotiations to report */
neg.bus_width = 8;
neg.sync_period = neg.sync_offset = 0;
neg.valid = (CCB_TRANS_BUS_WIDTH_VALID
| CCB_TRANS_SYNC_RATE_VALID | CCB_TRANS_SYNC_OFFSET_VALID);
/* drop all disconnected CCBs and clean negotiations */
for (targ=0; targ <= OUR_MAX_SUPPORTED_TARGET; targ++) {
clean_negotiations(softc, targ);
/* report the event if possible */
if (xpt_create_path(&path, /*periph*/NULL,
cam_sim_path(sim), targ,
CAM_LUN_WILDCARD) == CAM_REQ_CMP) {
xpt_async(AC_TRANSFER_NEG, path, &neg);
xpt_free_path(path);
}
for (lun=0; lun <= OUR_MAX_SUPPORTED_LUN; lun++)
for (h = softc->first_discon_hcb[targ][lun]; h != NULL; h = hh) {
hh=h->next;
free_hcb_and_ccb_done(h, h->ccb, CAM_SCSI_BUS_RESET);
}
}
ccb->ccb_h.status = CAM_REQ_CMP;
xpt_done(ccb);
/* report the event */
xpt_async(AC_BUS_RESET, softc->wpath, NULL);
return;
struct xxx_hcb *hcb, *h;
hcb = NULL;
/* We assume that softc->first_hcb is the head of the list of all
* HCBs associated with this bus, including those enqueued for
* processing, being processed by hardware and disconnected ones.
*/
for (h = softc->first_hcb; h != NULL; h = h->next) {
if (h->ccb == abort_ccb) {
hcb = h;
break;
}
}
if (hcb == NULL) {
/* no such CCB in our queue */
ccb->ccb_h.status = CAM_PATH_INVALID;
xpt_done(ccb);
return;
}
hcb=found_hcb;
int hstatus;
/* shown as a function, in case special action is needed to make
* this flag visible to hardware
*/
set_hcb_flags(hcb, HCB_BEING_ABORTED);
abort_again:
hstatus = get_hcb_status(hcb);
switch (hstatus) {
case HCB_SITTING_IN_QUEUE:
remove_hcb_from_hardware_queue(hcb);
/* FALLTHROUGH */
case HCB_COMPLETED:
/* this is an easy case */
free_hcb_and_ccb_done(hcb, abort_ccb, CAM_REQ_ABORTED);
break;
case HCB_BEING_TRANSFERRED:
untimeout(xxx_timeout, (caddr_t) hcb, abort_ccb->ccb_h.timeout_ch);
abort_ccb->ccb_h.timeout_ch =
timeout(xxx_timeout, (caddr_t) hcb, 10 * hz);
abort_ccb->ccb_h.status = CAM_REQ_ABORTED;
/* ask the controller to abort that HCB, then generate
* an interrupt and stop
*/
if (signal_hardware_to_abort_hcb_and_stop(hcb) < 0) {
/* oops, we missed the race with hardware, this transaction
* got off the bus before we aborted it, try again */
goto abort_again;
}
break;
secs_per_track - output, logical sectors per track
If the returned geometry differs much enough from what the SCSI controller BIOS thinks and a disk on this SCSI controller is used as bootable the system may not be able to boot. The typical calculation example taken from the aic7xxx driver is:
This gives the general idea, the exact calculation depends on the quirks of the particular BIOS. If BIOS provides no way set the "extended translation" flag in EEPROM this flag should normally be assumed equal to 1. Other popular geometries are:
int fatal=0;
struct ccb_trans_settings neg;
struct cam_path *path;
if (detected_scsi_reset(softc)
|| (fatal = detected_fatal_controller_error(softc))) {
int targ, lun;
struct xxx_hcb *h, *hh;
/* drop all enqueued CCBs */
for(h = softc->first_queued_hcb; h != NULL; h = hh) {
hh = h->next;
free_hcb_and_ccb_done(h, h->ccb, CAM_SCSI_BUS_RESET);
}
/* the clean values of negotiations to report */
neg.bus_width = 8;
neg.sync_period = neg.sync_offset = 0;
neg.valid = (CCB_TRANS_BUS_WIDTH_VALID
| CCB_TRANS_SYNC_RATE_VALID | CCB_TRANS_SYNC_OFFSET_VALID);
/* drop all disconnected CCBs and clean negotiations */
for (targ=0; targ <= OUR_MAX_SUPPORTED_TARGET; targ++) {
clean_negotiations(softc, targ);
/* report the event if possible */
if (xpt_create_path(&path, /*periph*/NULL,
cam_sim_path(sim), targ,
CAM_LUN_WILDCARD) == CAM_REQ_CMP) {
xpt_async(AC_TRANSFER_NEG, path, &neg);
xpt_free_path(path);
}
for (lun=0; lun <= OUR_MAX_SUPPORTED_LUN; lun++)
for (h = softc->first_discon_hcb[targ][lun]; h != NULL; h = hh) {
hh=h->next;
if (fatal)
free_hcb_and_ccb_done(h, h->ccb, CAM_UNREC_HBA_ERROR);
else
free_hcb_and_ccb_done(h, h->ccb, CAM_SCSI_BUS_RESET);
}
}
/* report the event */
xpt_async(AC_BUS_RESET, softc->wpath, NULL);
/* re-initialization may take a lot of time, in such case
* its completion should be signaled by another interrupt or
* checked on timeout - but for simplicity we assume here that
* it is really fast
*/
if (!fatal) {
reinitialize_controller_without_scsi_reset(softc);
} else {
reinitialize_controller_with_scsi_reset(softc);
}
schedule_next_hcb(softc);
return;
}
struct xxx_hcb *hcb, *h, *hh;
int hcb_status, scsi_status;
int ccb_status;
int targ;
int lun_to_freeze;
hcb = get_current_hcb(softc);
if (hcb == NULL) {
/* either stray interrupt or something went very wrong
* or this is something hardware-dependent
*/
handle as necessary;
return;
}
targ = hcb->target;
hcb_status = get_status_of_current_hcb(softc);
首先，我们检查 HCB 是否已完成，如果是，则检查返回的 SCSI 状态。
if (hcb_status == COMPLETED) {
scsi_status = get_completion_status(hcb);
if (hcb->flags & DOING_AUTOSENSE)
goto autosense_failed;
switch (hcb_status) {
我们考虑的下一个事件是意外断开连接。在 ABORT 或 BUS DEVICE RESET 消息后被视为正常，其他情况下视为异常。
case UNEXPECTED_DISCONNECT:
if (requested_abort(hcb)) {
/* abort affects all commands on that target+LUN, so
* mark all disconnected HCBs on that target+LUN as aborted too
*/
for (h = softc->first_discon_hcb[hcb->target][hcb->lun];
h != NULL; h = hh) {
hh=h->next;
free_hcb_and_ccb_done(h, h->ccb, CAM_REQ_ABORTED);
}
ccb_status = CAM_REQ_ABORTED;
} else if (requested_bus_device_reset(hcb)) {
int lun;
/* reset affects all commands on that target, so
* mark all disconnected HCBs on that target+LUN as reset
*/
for (lun=0; lun <= OUR_MAX_SUPPORTED_LUN; lun++)
for (h = softc->first_discon_hcb[hcb->target][lun];
h != NULL; h = hh) {
hh=h->next;
free_hcb_and_ccb_done(h, h->ccb, CAM_SCSI_BUS_RESET);
}
/* send event */
xpt_async(AC_SENT_BDR, hcb->ccb->ccb_h.path_id, NULL);
/* this was the CAM_RESET_DEV request itself, it is completed */
ccb_status = CAM_REQ_CMP;
} else {
calculate_residue(hcb);
ccb_status = CAM_UNEXP_BUSFREE;
/* request the further code to freeze the queue */
hcb->ccb->ccb_h.status |= CAM_DEV_QFRZN;
lun_to_freeze = hcb->lun;
}
break;
如果目标拒绝接受标签，我们通知 CAM 并将返回该 LUN 的所有命令。
case TAGS_REJECTED:
/* report the event */
neg.flags = 0 & ~CCB_TRANS_TAG_ENB;
neg.valid = CCB_TRANS_TQ_VALID;
xpt_async(AC_TRANSFER_NEG, hcb->ccb.ccb_h.path_id, &neg);
ccb_status = CAM_MSG_REJECT_REC;
/* request the further code to freeze the queue */
hcb->ccb->ccb_h.status |= CAM_DEV_QFRZN;
lun_to_freeze = hcb->lun;
break;
然后我们检查其他一些条件，处理基本上仅限于设置 CCB 状态：
case SELECTION_TIMEOUT:
ccb_status = CAM_SEL_TIMEOUT;
/* request the further code to freeze the queue */
hcb->ccb->ccb_h.status |= CAM_DEV_QFRZN;
lun_to_freeze = CAM_LUN_WILDCARD;
break;
case PARITY_ERROR:
ccb_status = CAM_UNCOR_PARITY;
break;
case DATA_OVERRUN:
case ODD_WIDE_TRANSFER:
ccb_status = CAM_DATA_RUN_ERR;
break;
default:
/* all other errors are handled in a generic way */
ccb_status = CAM_REQ_CMP_ERR;
/* request the further code to freeze the queue */
hcb->ccb->ccb_h.status |= CAM_DEV_QFRZN;
lun_to_freeze = CAM_LUN_WILDCARD;
break;
}
然后我们检查错误是否严重到需要冻结输入队列直到处理完毕，如果是，则执行：
if (hcb->ccb->ccb_h.status & CAM_DEV_QFRZN) {
/* freeze the queue */
xpt_freeze_devq(ccb->ccb_h.path, /*count*/1);
/* re-queue all commands for this target/LUN back to CAM */
for (h = softc->first_queued_hcb; h != NULL; h = hh) {
hh = h->next;
if (targ == h->targ
&& (lun_to_freeze == CAM_LUN_WILDCARD || lun_to_freeze == h->lun))
free_hcb_and_ccb_done(h, h->ccb, CAM_REQUEUE_REQ);
}
}
free_hcb_and_ccb_done(hcb, hcb->ccb, ccb_status);
schedule_next_hcb(softc);
return;
