scsimgrlib.c

VXWORKS源代码

    }


/*******************************************************************************
*
* scsiMgrPhysDevRunnableThreadGet - find a runnable thread on this phys dev
*
* If the physical device is connected, no new thread can be started.
* Otherwise, the thread at the front of the wait queue is the only thread to
* consider (it is the highest priority thread waiting for access to this
* device).  If there is such a thread, consider its tag type and the current
* nexus type on the physical device to determine whether or not the thread
* can be started.
*
* Essentially, if the device currently has an ITL nexus it cannot have any
* new threads started.  If it has an ITLQ nexus, another tagged thread can be
* started provided there is a tag available, or a sense recovery (untagged)
* thread can be started.
*
* RETURNS: the highest priority thread which can be started on this device,
* or 0 if no threads are available or the device can't start a new thread.
*/
LOCAL SCSI_THREAD * scsiMgrPhysDevRunnableThreadGet
    (
    SCSI_PHYS_DEV * pScsiPhysDev
    )
    {
    BOOL          canStart;
    SCSI_THREAD * pThread;
    
    if (pScsiPhysDev->connected)
	return (NULL);

    pThread = (SCSI_THREAD *) lstFirst (&pScsiPhysDev->waitingThreads);

    if (pThread == 0)
	return (NULL);
    
    switch (pScsiPhysDev->nexus)
	{
	case SCSI_NEXUS_NONE:
	    canStart = TRUE;
	    break;

	case SCSI_NEXUS_ITL:
	    canStart = FALSE;
	    break;

	case SCSI_NEXUS_ITLQ:
	    canStart = (pScsiPhysDev->nFreeTags != 0) ||
		       (pThread->tagType == SCSI_TAG_SENSE_RECOVERY);
	    break;

	default:
	    logMsg ("scsiMgrPhysDevRunnableThreadGet: device 0x%08x: "
		    "invalid nexus (%d)\n",
		    (int) pScsiPhysDev, pScsiPhysDev->nexus, 0, 0, 0, 0);
	    canStart = FALSE;
	    break;
	}

    return (canStart ? pThread : 0);
    }


/*******************************************************************************
*
* scsiMgrPhysDevActiveQAdd - add a thread to a phys dev's active queue
*
* Simply insert the thread onto the list.  The list is unordered.
*
* RETURNS: N/A
*/
LOCAL void scsiMgrPhysDevActiveQAdd
    (
    SCSI_PHYS_DEV * pScsiPhysDev,
    SCSI_THREAD   * pThread
    )
    {
    lstInsert (&pScsiPhysDev->activeThreads, 0, (NODE *) pThread);
    }


/*******************************************************************************
*
* scsiMgrPhysDevActiveQRemove - remove a thread from a phys dev's active queue
*
* NOTE:
* It would be nice if "lstDelete()" told you whether or not the target node
* was on the list - then three would be no need to have the "lstFind" first.
*
* RETURNS: OK, or ERROR if the thread was not on the queue.
*/
LOCAL STATUS scsiMgrPhysDevActiveQRemove
    (
    SCSI_PHYS_DEV * pScsiPhysDev,
    SCSI_THREAD   * pThread
    )
    {
    if (lstFind (&pScsiPhysDev->activeThreads, (NODE *) pThread) == ERROR)
	return (ERROR);
    
    lstDelete (&pScsiPhysDev->activeThreads, (NODE *) pThread);

    return (OK);
    }


/*******************************************************************************
*
* scsiMgrPhysDevActiveThreadFind - find thread corresponding to tag on phys dev
*
* Search the physical device's active thread list to find one corresponding to
* the given tag number.
*
* NOTE:
* This function should not be called by application programs.
*
* RETURNS: thread ptr, or 0 if no active thread corresponding to this tag
*
* NOMANUAL
*/
SCSI_THREAD * scsiMgrPhysDevActiveThreadFind
    (
    SCSI_PHYS_DEV * pScsiPhysDev,	/* physical device to search    */
    SCSI_TAG        tagNum		/* tag number, or SCSI_TAG_NONE */
    )
    {
    SCSI_THREAD * pThread;

    for (pThread  = (SCSI_THREAD *) lstFirst (&pScsiPhysDev->activeThreads);
	 pThread != 0;
	 pThread  = (SCSI_THREAD *) lstNext ((NODE *) pThread))
	{
	if (pThread->tagNumber == tagNum)
	    return (pThread);
	}

    return (0);
    }


/*******************************************************************************
*
* scsiMgrPhysDevTagInit - initialise tag table for a physical device
*
* Set all tags not in use; reset the free tag count and next free tag number.
*
* RETURNS: N/A
*
* NOMANUAL
*/
VOID scsiMgrPhysDevTagInit
    (
    SCSI_PHYS_DEV * pScsiPhysDev
    )
    {
    UINT     nTags = pScsiPhysDev->nTags;
    SCSI_TAG tagNum;

    /*
     *	Initialise "dummy" tag used for untagged threads
     */
    pScsiPhysDev->untagged.inUse = FALSE;

    /*
     *	Set all real tags to "available"
     */
    for (tagNum = 0; tagNum < nTags; ++tagNum)
	{
	SCSI_TAG_INFO * pTag = pScsiPhysDev->pTagInfo + tagNum;

	pTag->inUse = FALSE;
	}

    pScsiPhysDev->nFreeTags = nTags;
    pScsiPhysDev->nextTag   = (nTags == 0) ? SCSI_TAG_NONE : 0;
    }


/*******************************************************************************
*
* scsiMgrPhysDevTagAllocate - allocate a tag number on the physical device
*
* Validate the requested tag type; if it is tagged, allocate a tag number
* on the physical device.
*
* The actual tag number allocated has no significance other than that it
* identifies an active thread on the physical device.  In particular, it has
* no bearing on the order in which the target executes the command.  Thus the
* choice of tag number is somewhat arbitrary; however, this routine attempts
* to use tags in rotation rather than continually re-using the same tag
* numbers.  (This is primarily because it makes debugging somewhat easier.)
*
* NOTE:
* An incorrect tag type can result from a bad choice by the client, however
* unavailability of free tags can only result from software failure (the SCSI
* manager should not be activating a thread on a device which has no tags
* free !)
*
* The search for a free tag could get quite slow when the device supports a
* large number of tags and they are nearly all in use.  In practice this is
* not likely to cause problems even with the simple scheme used currently.
* A more sophisticated approach would be to store free tag numbers on a
* list or queue, however this would use substantial amounts of memory (up to
* 256 free tags per physical device).
*
* RETURNS: OK, or ERROR if no tags available
*/
LOCAL STATUS scsiMgrPhysDevTagAllocate
    (
    SCSI_PHYS_DEV * pScsiPhysDev,
    SCSI_TAG_TYPE   tagType,
    SCSI_TAG      * pTagNum
    )
    {
    BOOL     tagged;
    SCSI_TAG tagNum;
    SCSI_TAG_INFO * pTag = 0;		/* initialise to avoid warning */

    if (scsiMgrPhysDevTagTypeValidate (pScsiPhysDev, tagType, &tagged) != OK)
	return (ERROR);
    
    if (!tagged)
	{
    	tagNum = SCSI_TAG_NONE;

	pTag = &pScsiPhysDev->untagged;
	}
    else
	{
	int i;

	if (pScsiPhysDev->nFreeTags == 0)
	    {
	    logMsg ("scsiMgrPhysDevTagAllocate: device 0x%08x: no free tags\n",
		    (int) pScsiPhysDev, 0, 0, 0, 0, 0);

	    errnoSet (S_scsiLib_SOFTWARE_ERROR);
	    return (ERROR);
	    }

	--pScsiPhysDev->nFreeTags;

	/*
	 *  Search for a free tag; starting at one after we last used
	 */
    	tagNum = pScsiPhysDev->nextTag;

	for (i = 0; i < pScsiPhysDev->nTags; ++i)
	    {
	    pTag = (pScsiPhysDev->pTagInfo + tagNum);

	    if (!pTag->inUse)
		break;

	    if (++tagNum >= pScsiPhysDev->nTags)
		tagNum = 0;
	    }

	if (i == pScsiPhysDev->nTags)
	    {
	    logMsg ("scsiMgrPhysDevTagAllocate: device 0x%08x: "
		    "tag not found (%d free)\n",
		    (int) pScsiPhysDev, pScsiPhysDev->nTags, 0, 0, 0, 0);

	    errnoSet (S_scsiLib_SOFTWARE_ERROR);
	    return (ERROR);
	    }

	if ((pScsiPhysDev->nextTag = tagNum + 1) == pScsiPhysDev->nTags)
	    pScsiPhysDev->nextTag = 0;
	}
    
    pTag->inUse = TRUE;

    *pTagNum = tagNum;

    return (OK);
    }


/*******************************************************************************
*
* scsiMgrPhysDevTagFree - free a tag for the physical device.
*
* Mark the specified tag not in use.
*
* RETURNS: OK, or ERROR if no tags available
*/
LOCAL void scsiMgrPhysDevTagFree
    (
    SCSI_PHYS_DEV * pScsiPhysDev,
    SCSI_TAG        tagNum
    )
    {
    SCSI_TAG_INFO * pTag;

    if (tagNum == SCSI_TAG_NONE)
	{
	pTag = &pScsiPhysDev->untagged;
	}
    else
	{
	++pScsiPhysDev->nFreeTags;

    	pTag = (pScsiPhysDev->pTagInfo + tagNum);
	}

    pTag->inUse = FALSE;
    }


/*******************************************************************************
*
* scsiMgrPhysDevTagTypeValidate - validate requested tag type for phys dev
*
* Check the requested tag type is valid given the current nexus type of the
* device.  Note the special cases which allow an untagged sense recovery
* command to be started when the device has tagged nexuses active, provided
* it is in a contingent allegiance condition.
*
* RETURNS: OK, or ERROR if the requested tag type is (currently) invalid
*/
LOCAL STATUS scsiMgrPhysDevTagTypeValidate
    (
    SCSI_PHYS_DEV * pScsiPhysDev,
    SCSI_TAG_TYPE   tagType,
    BOOL          * pTagged
    )
    {
    BOOL valid;
    BOOL tagged;
    
    switch (tagType)
	{
    	case SCSI_TAG_UNTAGGED:
	    valid  = (pScsiPhysDev->nexus != SCSI_NEXUS_ITLQ);
	    tagged = FALSE;
	    break;

	case SCSI_TAG_SENSE_RECOVERY:
	    valid  = (pScsiPhysDev->nexus != SCSI_NEXUS_ITLQ) ||
		     pScsiPhysDev->pendingCA;
	    tagged = FALSE;
	    break;

	case SCSI_TAG_SIMPLE:
	case SCSI_TAG_ORDERED:
	case SCSI_TAG_HEAD_OF_Q:
	    valid  = (pScsiPhysDev->nexus   != SCSI_NEXUS_ITL) &&
		     (pScsiPhysDev->tagType != SCSI_TAG_UNTAGGED);
	    tagged = TRUE;
	    break;
	    
    	default:
	    valid  = FALSE;
	    tagged = FALSE;
	    break;
	}

    if (!valid)
	{
	SCSI_DEBUG_MSG ("scsiPhysDevTagTypeValidate: invalid tag type (%d) "
			"for device 0x%08x\n",
			tagType, (int) pScsiPhysDev, 0, 0, 0, 0);

	errnoSet (S_scsiLib_INVALID_TAG_TYPE);

	return (ERROR);
	}
	
    *pTagged = tagged;
	
    return (OK);
    }

/*******************************************************************************
*
* scsiMgrShow - show status information for the SCSI manager
*
* This routine shows the current state of the SCSI manager for the specified
* controller, including the total number of threads created and the number of
* threads currently free.
*
* Optionally, this routine also shows details for all created physical devices 
* on this controller and all threads for which SCSI requests are outstanding.
* It also shows the IDs of all free threads.
*
* NOTE: The information displayed is volatile; this routine is best used when
* there is no activity on the SCSI bus.  Threads allocated by a client but
* for which there are no outstanding SCSI requests are not shown.
*
* RETURNS: N/A
*/
void scsiMgrShow
    (
    SCSI_CTRL * pScsiCtrl,		/* SCSI controller to use        */
    BOOL        showPhysDevs,		/* TRUE => show phys dev details */
    BOOL        showThreads,		/* TRUE => show thread details   */
    BOOL        showFreeThreads		/* TRUE => show free thread IDs  */
    )
    {
    char * state;
    int    nFree;
    
    if (pScsiCtrl == NULL)
	pScsiCtrl = pSysScsiCtrl;
    
    if (pScsiCtrl == NULL)
	{
	printf ("No SCSI controller specified.\n");
	return;
	}

    state = pScsiCtrl->active ? "active" : "inactive";
    
    nFree = lstCount (&pScsiCtrl->freeThreads);
    
    printf ("Controller   State    # Threads (tot/free)\n");
    printf ("----------  --------  --------------------\n");

    printf ("0x%08x  %-8s        %3d  %3d\n",
	    (int) pScsiCtrl,
	    state,
	    pScsiCtrl->nThreads,
	    nFree);

    if (showPhysDevs)
	{
	BOOL noHeader = FALSE;
	int  i;

	printf ("\n");

	for (i = 0; i < SCSI_MAX_PHYS_DEVS; ++i)
	    {
	    SCSI_PHYS_DEV * pScsiPhysDev = pScsiCtrl->physDevArr[i];

	    if (pScsiPhysDev != 0)
		{
		scsiPhysDevShow (pScsiPhysDev, FALSE, noHeader);

		noHeader = TRUE;
		}
	    }
	}

    if (showThreads)
	{
	/*
	 *  This is crude.  A better approach would be to collect all
	 *  the thread IDs into a buffer, then sort by priority before
	 *  calling "scsiThreadShow" for each thread.
	 */
	int i;

	printf ("\n");

	for (i = 0; i < SCSI_MAX_PHYS_DEVS; ++i)
	    {
	    SCSI_PHYS_DEV * pScsiPhysDev = pScsiCtrl->physDevArr[i];

	    if (pScsiPhysDev != 0)
		{
		scsiThreadListShow (&pScsiPhysDev->activeThreads);
		scsiThreadListShow (&pScsiPhysDev->waitingThreads);
		}
	    }
	}

    if (showFreeThreads && (nFree != 0))
	{
	printf ("\nFree threads:\n");

	scsiThreadListIdShow (&pScsiCtrl->freeThreads);
	}
    }