[SCSI 53c700] add specimen block layer tcq

drivers/scsi/53c700.c

@@ -284,6 +284,7 @@ NCR_700_detect(Scsi_Host_Template *tpnt,
 	tpnt->cmd_per_lun = NCR_700_MAX_TAGS;
 	tpnt->use_clustering = DISABLE_CLUSTERING;
 	tpnt->proc_info = NCR_700_proc_directory_info;
+	tpnt->use_blk_tcq = 1;
 	
 	if(tpnt->name == NULL)
 		tpnt->name = "53c700";
@@ -499,46 +500,12 @@ STATIC void
 free_slot(struct NCR_700_command_slot *slot,
 	  struct NCR_700_Host_Parameters *hostdata)
 {
-	int hash;
-	struct NCR_700_command_slot **forw, **back;
-
-
 	if((slot->state & NCR_700_SLOT_MASK) != NCR_700_SLOT_MAGIC) {
 		printk(KERN_ERR "53c700: SLOT %p is not MAGIC!!!\n", slot);
 	}
 	if(slot->state == NCR_700_SLOT_FREE) {
 		printk(KERN_ERR "53c700: SLOT %p is FREE!!!\n", slot);
 	}
-	/* remove from queues */
-	if(slot->tag != NCR_700_NO_TAG) {
-		hash = hash_ITLQ(slot->cmnd->target, slot->cmnd->lun,
-				 slot->tag);
-		if(slot->ITLQ_forw == NULL)
-			back = &hostdata->ITLQ_Hash_back[hash];
-		else
-			back = &slot->ITLQ_forw->ITLQ_back;
-
-		if(slot->ITLQ_back == NULL)
-			forw = &hostdata->ITLQ_Hash_forw[hash];
-		else
-			forw = &slot->ITLQ_back->ITLQ_forw;
-
-		*forw = slot->ITLQ_forw;
-		*back = slot->ITLQ_back;
-	}
-	hash = hash_ITL(slot->cmnd->target, slot->cmnd->lun);
-	if(slot->ITL_forw == NULL)
-		back = &hostdata->ITL_Hash_back[hash];
-	else
-		back = &slot->ITL_forw->ITL_back;
-	
-	if(slot->ITL_back == NULL)
-		forw = &hostdata->ITL_Hash_forw[hash];
-	else
-		forw = &slot->ITL_back->ITL_forw;
-	
-	*forw = slot->ITL_forw;
-	*back = slot->ITL_back;
 	
 	slot->resume_offset = 0;
 	slot->cmnd = NULL;
@@ -566,48 +533,6 @@ save_for_reselection(struct NCR_700_Host_Parameters *hostdata,
 	hostdata->cmd = NULL;
 }
 
-/* Most likely nexus is the oldest in each case */
-STATIC inline struct NCR_700_command_slot *
-find_ITL_Nexus(struct NCR_700_Host_Parameters *hostdata, __u8 pun, __u8 lun)
-{
-	int hash = hash_ITL(pun, lun);
-	struct NCR_700_command_slot *slot = hostdata->ITL_Hash_back[hash];
-	while(slot != NULL && !(slot->cmnd->target == pun &&
-				slot->cmnd->lun == lun))
-		slot = slot->ITL_back;
-	return slot;
-}
-
-STATIC inline struct NCR_700_command_slot *
-find_ITLQ_Nexus(struct NCR_700_Host_Parameters *hostdata, __u8 pun,
-		__u8 lun, __u8 tag)
-{
-	int hash = hash_ITLQ(pun, lun, tag);
-	struct NCR_700_command_slot *slot = hostdata->ITLQ_Hash_back[hash];
-
-	while(slot != NULL && !(slot->cmnd->target == pun 
-	      && slot->cmnd->lun == lun && slot->tag == tag))
-		slot = slot->ITLQ_back;
-
-#ifdef NCR_700_TAG_DEBUG
-	if(slot != NULL) {
-		struct NCR_700_command_slot *n = slot->ITLQ_back;
-		while(n != NULL && n->cmnd->target != pun
-		      && n->cmnd->lun != lun && n->tag != tag)
-			n = n->ITLQ_back;
-
-		if(n != NULL && n->cmnd->target == pun && n->cmnd->lun == lun
-		   && n->tag == tag) {
-			printk(KERN_WARNING "53c700: WARNING: DUPLICATE tag %d\n",
-			       tag);
-		}
-	}
-#endif
-	return slot;
-}
-
-
-
 /* This translates the SDTR message offset and period to a value
  * which can be loaded into the SXFER_REG.
  *
@@ -697,7 +622,6 @@ NCR_700_scsi_done(struct NCR_700_Host_Parameters *hostdata,
 			SCp->underflow = SCp->old_underflow;
 			
 		}
-
 		free_slot(slot, hostdata);
 #ifdef NCR_700_DEBUG
 		if(NCR_700_get_depth(SCp->device) == 0 ||
@@ -1148,6 +1072,7 @@ process_script_interrupt(__u32 dsps, __u32 dsp, Scsi_Cmnd *SCp,
 		__u8 lun;
 		struct NCR_700_command_slot *slot;
 		__u8 reselection_id = hostdata->reselection_id;
+		Scsi_Device *SDp;
 
 		lun = hostdata->msgin[0] & 0x1f;
 
@@ -1155,34 +1080,39 @@ process_script_interrupt(__u32 dsps, __u32 dsp, Scsi_Cmnd *SCp,
 		DEBUG(("scsi%d: (%d:%d) RESELECTED!\n",
 		       host->host_no, reselection_id, lun));
 		/* clear the reselection indicator */
+		SDp = scsi_find_device(host, 0, reselection_id, lun);
+		if(unlikely(SDp == NULL)) {
+			printk(KERN_ERR "scsi%d: (%d:%d) HAS NO device\n",
+			       host->host_no, reselection_id, lun);
+			BUG();
+		}
 		if(hostdata->msgin[1] == A_SIMPLE_TAG_MSG) {
-			slot = find_ITLQ_Nexus(hostdata, reselection_id,
-					       lun, hostdata->msgin[2]);
+			Scsi_Cmnd *SCp = scsi_find_tag(SDp, hostdata->msgin[2]);
+			if(unlikely(SCp == NULL)) {
+				printk(KERN_ERR "scsi%d: (%d:%d) no saved request for tag %d\n", 
+				       host->host_no, reselection_id, lun, hostdata->msgin[2]);
+				BUG();
+			}
+
+			slot = (struct NCR_700_command_slot *)SCp->host_scribble;
+			DEBUG(("53c700: %d:%d:%d, reselection is tag %d, slot %p(%d)\n",
+			       host->host_no, SDp->id, SDp->lun,
+			       hostdata->msgin[2], slot, slot->tag));
 		} else {
-			slot = find_ITL_Nexus(hostdata, reselection_id, lun);
+			Scsi_Cmnd *SCp = scsi_find_tag(SDp, SCSI_NO_TAG);
+			if(unlikely(SCp == NULL)) {
+				printk(KERN_ERR "scsi%d: (%d:%d) no saved request for untagged cmd\n", 
+				       host->host_no, reselection_id, lun);
+				BUG();
+			}
+			slot = (struct NCR_700_command_slot *)SCp->host_scribble;
 		}
-	retry:
+
 		if(slot == NULL) {
-			struct NCR_700_command_slot *s = find_ITL_Nexus(hostdata, reselection_id, lun);
 			printk(KERN_ERR "scsi%d: (%d:%d) RESELECTED but no saved command (MSG = %02x %02x %02x)!!\n",
 			       host->host_no, reselection_id, lun,
 			       hostdata->msgin[0], hostdata->msgin[1],
 			       hostdata->msgin[2]);
-			printk(KERN_ERR " OUTSTANDING TAGS:");
-			while(s != NULL) {
-				if(s->cmnd->target == reselection_id &&
-				   s->cmnd->lun == lun) {
-					printk("%d ", s->tag);
-					if(s->tag == hostdata->msgin[2]) {
-						printk(" ***FOUND*** \n");
-						slot = s;
-						goto retry;
-					}
-						
-				}
-				s = s->ITL_back;
-			}
-			printk("\n");
 		} else {
 			if(hostdata->state != NCR_700_HOST_BUSY)
 				printk(KERN_ERR "scsi%d: FATAL, host not busy during valid reselection!\n",
@@ -1474,9 +1404,8 @@ NCR_700_start_command(Scsi_Cmnd *SCp)
 	 * will refuse all tags, so send the request sense as untagged
 	 * */
 	if((hostdata->tag_negotiated & (1<<SCp->target))
-	   && (slot->tag != NCR_700_NO_TAG && SCp->cmnd[0] != REQUEST_SENSE)) {
-		hostdata->msgout[count++] = A_SIMPLE_TAG_MSG;
-		hostdata->msgout[count++] = slot->tag;
+	   && (slot->tag != SCSI_NO_TAG && SCp->cmnd[0] != REQUEST_SENSE)) {
+		count += scsi_populate_tag_msg(SCp, &hostdata->msgout[count]);
 	}
 
 	if(hostdata->fast &&
@@ -1836,7 +1765,6 @@ NCR_700_queuecommand(Scsi_Cmnd *SCp, void (*done)(Scsi_Cmnd *))
 	__u32 move_ins;
 	int pci_direction;
 	struct NCR_700_command_slot *slot;
-	int hash;
 
 	if(hostdata->command_slot_count >= NCR_700_COMMAND_SLOTS_PER_HOST) {
 		/* We're over our allocation, this should never happen
@@ -1844,7 +1772,15 @@ NCR_700_queuecommand(Scsi_Cmnd *SCp, void (*done)(Scsi_Cmnd *))
 		printk(KERN_WARNING "scsi%d: Command depth has gone over queue depth\n", SCp->host->host_no);
 		return 1;
 	}
-	if(NCR_700_get_depth(SCp->device) != 0 && !(hostdata->tag_negotiated & (1<<SCp->target))) {
+	/* check for untagged commands.  We cannot have any outstanding
+	 * commands if we accept them.  Commands could be untagged because:
+	 *
+	 * - The tag negotiated bitmap is clear
+	 * - The blk layer sent and untagged command
+	 */
+	if(NCR_700_get_depth(SCp->device) != 0
+	   && (!(hostdata->tag_negotiated & (1<<SCp->target))
+	       || !blk_rq_tagged(SCp->request))) {
 		DEBUG((KERN_ERR "scsi%d (%d:%d) has non zero depth %d\n",
 		       SCp->host->host_no, SCp->target, SCp->lun,
 		       NCR_700_get_depth(SCp->device)));
@@ -1883,84 +1819,40 @@ NCR_700_queuecommand(Scsi_Cmnd *SCp, void (*done)(Scsi_Cmnd *))
 		 * NOTE: There is a danger here: the mid layer supports
 		 * tag queuing per LUN.  We only support it per PUN because
 		 * of potential reselection issues */
+		printk(KERN_NOTICE "scsi%d: (%d:%d) beginning blk layer TCQ\n",
+		       SCp->device->host->host_no, SCp->target, SCp->lun);
+		scsi_activate_tcq(SCp->device, NCR_700_MAX_TAGS);
+	}
+
+	if(blk_rq_tagged(SCp->request)
+	   && (hostdata->tag_negotiated &(1<<SCp->target)) == 0) {
 		printk(KERN_INFO "scsi%d: (%d:%d) Enabling Tag Command Queuing\n", SCp->device->host->host_no, SCp->target, SCp->lun);
 		hostdata->tag_negotiated |= (1<<SCp->target);
 		NCR_700_set_flag(SCp->device, NCR_700_DEV_BEGIN_TAG_QUEUEING);
-		SCp->device->tagged_queue = 1;
 	}
 
-	if(hostdata->tag_negotiated &(1<<SCp->target)) {
-
-		struct NCR_700_command_slot *old =
-			find_ITL_Nexus(hostdata, SCp->target, SCp->lun);
-#ifdef NCR_700_TAG_DEBUG
-		struct NCR_700_command_slot *found;
-#endif
-		
-		if(old != NULL && old->tag == SCp->device->current_tag) {
-			/* On some badly starving drives, this can be
-			 * a frequent occurance, so print the message
-			 * only once */
-			if(NCR_700_is_flag_clear(SCp->device, NCR_700_DEV_TAG_STARVATION_WARNED)) {
-				printk(KERN_WARNING "scsi%d (%d:%d) Target is suffering from tag starvation.\n", SCp->host->host_no, SCp->target, SCp->lun);
-				NCR_700_set_flag(SCp->device, NCR_700_DEV_TAG_STARVATION_WARNED);
-			}
-			/* Release the slot and ajust the depth before refusing
-			 * the command */
-			free_slot(slot, hostdata);
-			NCR_700_set_depth(SCp->device, NCR_700_get_depth(SCp->device) - 1);
-			return 1;
-		}
-		slot->tag = SCp->device->current_tag++;
-#ifdef NCR_700_TAG_DEBUG
-		while((found = find_ITLQ_Nexus(hostdata, SCp->target, SCp->lun, slot->tag)) != NULL) {
-			printk("\n\n**ERROR** already using tag %d, but oldest is %d\n", slot->tag, (old == NULL) ? -1 : old->tag);
-			printk("  FOUND = %p, tag = %d, pun = %d, lun = %d\n",
-			       found, found->tag, found->cmnd->target, found->cmnd->lun);
-			slot->tag = SCp->device->current_tag++;
-			printk("   Tag list is: ");
-			while(old != NULL) {
-				if(old->cmnd->target == SCp->target &&
-				   old->cmnd->lun == SCp->lun)
-					printk("%d ", old->tag);
-				old = old->ITL_back;
-			}
-			printk("\n\n");
-		}
-#endif
-		hash = hash_ITLQ(SCp->target, SCp->lun, slot->tag);
-		/* link into the ITLQ hash queues */
-		slot->ITLQ_forw = hostdata->ITLQ_Hash_forw[hash];
-		hostdata->ITLQ_Hash_forw[hash] = slot;
-#ifdef NCR_700_TAG_DEBUG
-		if(slot->ITLQ_forw != NULL && slot->ITLQ_forw->ITLQ_back != NULL) {
-			printk(KERN_ERR "scsi%d (%d:%d) ITLQ_back is not NULL!!!!\n", SCp->host->host_no, SCp->target, SCp->lun);
+	/* here we may have to process an untagged command.  The gate
+	 * above ensures that this will be the only one outstanding,
+	 * so clear the tag negotiated bit.
+	 *
+	 * FIXME: This will royally screw up on multiple LUN devices
+	 * */
+	if(!blk_rq_tagged(SCp->request)
+	   && (hostdata->tag_negotiated &(1<<SCp->target))) {
+		printk(KERN_INFO "scsi%d: (%d:%d) Disabling Tag Command Queuing\n", SCp->device->host->host_no, SCp->target, SCp->lun);
+		hostdata->tag_negotiated &= ~(1<<SCp->target);
 	}
-#endif
-		if(slot->ITLQ_forw != NULL)
-			slot->ITLQ_forw->ITLQ_back = slot;
-		else
-			hostdata->ITLQ_Hash_back[hash] = slot;
-		slot->ITLQ_back = NULL;
+
+	if((hostdata->tag_negotiated &(1<<SCp->target))) {
+		slot->tag = SCp->request->tag;
+		DEBUG(("53c700 %d:%d:%d, sending out tag %d, slot %p\n",
+		       SCp->host->host_no, SCp->target, SCp->lun, slot->tag,
+		       slot));
 	} else {
-		slot->tag = NCR_700_NO_TAG;
-	}
-	/* link into the ITL hash queues */
-	hash = hash_ITL(SCp->target, SCp->lun);
-	slot->ITL_forw = hostdata->ITL_Hash_forw[hash];
-	hostdata->ITL_Hash_forw[hash] = slot;
-#ifdef NCR_700_TAG_DEBUG
-	if(slot->ITL_forw != NULL && slot->ITL_forw->ITL_back != NULL) {
-		printk(KERN_ERR "scsi%d (%d:%d) ITL_back is not NULL!!!!\n",
-		       SCp->host->host_no, SCp->target, SCp->lun);
+		slot->tag = SCSI_NO_TAG;
+		/* must populate current_cmnd for scsi_find_tag to work */
+		SCp->device->current_cmnd = SCp;
 	}
-#endif
-	if(slot->ITL_forw != NULL)
-		slot->ITL_forw->ITL_back = slot;
-	else
-		hostdata->ITL_Hash_back[hash] = slot;
-	slot->ITL_back = NULL;
-
 	/* sanity check: some of the commands generated by the mid-layer
 	 * have an eccentric idea of their sc_data_direction */
 	if(!SCp->use_sg && !SCp->request_bufflen 
@@ -2054,16 +1946,12 @@ STATIC int
 NCR_700_abort(Scsi_Cmnd * SCp)
 {
 	struct NCR_700_command_slot *slot;
-	struct NCR_700_Host_Parameters *hostdata = 
-		(struct NCR_700_Host_Parameters *)SCp->host->hostdata[0];
 
 	printk(KERN_INFO "scsi%d (%d:%d) New error handler wants to abort command\n\t",
 	       SCp->host->host_no, SCp->target, SCp->lun);
 	print_command(SCp->cmnd);
 
-	slot = find_ITL_Nexus(hostdata, SCp->target, SCp->lun);
-	while(slot != NULL && slot->cmnd != SCp)
-		slot = slot->ITL_back;
+	slot = (struct NCR_700_command_slot *)SCp->host_scribble;
 
 	if(slot == NULL)
 		/* no outstanding command to abort */

drivers/scsi/53c700.h

@@ -189,8 +189,7 @@ struct NCR_700_command_slot {
 	#define NCR_700_SLOT_BUSY (1|NCR_700_SLOT_MAGIC) /* slot has command active on HA */
 	#define NCR_700_SLOT_QUEUED (2|NCR_700_SLOT_MAGIC) /* slot has command to be made active on HA */
 	__u8	state;
-	#define NCR_700_NO_TAG	0xdead
-	__u16	tag;
+	int	tag;
 	__u32	resume_offset;
 	Scsi_Cmnd	*cmnd;
 	/* The pci_mapped address of the actual command in cmnd */