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Commit cd62b7da authored by Douglas Gilbert's avatar Douglas Gilbert Committed by Christoph Hellwig
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scsi_debug: give unit attention and other errors precedence over TSF 



Give existing errors priority over the generation of Task
Set Full (TSF) errors. So that max_queue is not exceeded,
existing errors may be sent back in the invocation thread.
This is done so errors like Unit Attentions are not hidden
and lost by either max_queue exceeded or real/injected
TSFs.

Signed-off-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 01123ef4

drivers/scsi/scsi_debug.c

+33 −34
Original line number Diff line number Diff line
@@ -3006,7 +3006,7 @@ schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip, 
	      int scsi_result, int delta_jiff)

{

	unsigned long iflags;

	int k, num_in_q, tsf, qdepth, inject;

	int k, num_in_q, qdepth, inject;

	struct sdebug_queued_cmd *sqcp = NULL;

	struct scsi_device *sdp = cmnd->device;
@@ -3019,55 +3019,48 @@ schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip, 
	if ((scsi_result) && (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))

		sdev_printk(KERN_INFO, sdp, "%s: non-zero result=0x%x\n",

			    __func__, scsi_result);

	if (delta_jiff == 0) {

		/* using same thread to call back mid-layer */

		cmnd->result = scsi_result;

		cmnd->scsi_done(cmnd);

		return 0;

	}

	if (delta_jiff == 0)

		goto respond_in_thread;



	/* deferred response cases */

	/* schedule the response at a later time if resources permit */

	spin_lock_irqsave(&queued_arr_lock, iflags);

	num_in_q = atomic_read(&devip->num_in_q);

	qdepth = cmnd->device->queue_depth;

	k = find_first_zero_bit(queued_in_use_bm, scsi_debug_max_queue);

	tsf = 0;

	inject = 0;

	if ((qdepth > 0) && (num_in_q >= qdepth))

		tsf = 1;

	else if ((scsi_debug_every_nth != 0) &&

		 (SCSI_DEBUG_OPT_RARE_TSF & scsi_debug_opts)) {

	if ((qdepth > 0) && (num_in_q >= qdepth)) {

		if (scsi_result) {

			spin_unlock_irqrestore(&queued_arr_lock, iflags);

			goto respond_in_thread;

		} else

			scsi_result = device_qfull_result;

	} else if ((scsi_debug_every_nth != 0) &&

		   (SCSI_DEBUG_OPT_RARE_TSF & scsi_debug_opts) &&

		   (scsi_result == 0)) {

		if ((num_in_q == (qdepth - 1)) &&

		    (atomic_inc_return(&sdebug_a_tsf) >=

		     abs(scsi_debug_every_nth))) {

			atomic_set(&sdebug_a_tsf, 0);

			inject = 1;

			tsf = 1;

			scsi_result = device_qfull_result;

		}

	}



	/* if (tsf) simulate device reporting SCSI status of TASK SET FULL.

	 * Might override existing CHECK CONDITION. */

	if (tsf)

		scsi_result = device_qfull_result;

	k = find_first_zero_bit(queued_in_use_bm, scsi_debug_max_queue);

	if (k >= scsi_debug_max_queue) {

		if (SCSI_DEBUG_OPT_ALL_TSF & scsi_debug_opts)

			tsf = 1;

		spin_unlock_irqrestore(&queued_arr_lock, iflags);

		if (scsi_result)

			goto respond_in_thread;

		else if (SCSI_DEBUG_OPT_ALL_TSF & scsi_debug_opts)

			scsi_result = device_qfull_result;

		if (SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts)

			sdev_printk(KERN_INFO, sdp,

				    "%s: num_in_q=%d, bypass q, %s%s\n",

				    __func__, num_in_q,

				    (inject ? "<inject> " : ""),

				    (tsf ?  "status: TASK SET FULL" :

				    "%s: max_queue=%d exceeded, %s\n",

				    __func__, scsi_debug_max_queue,

				    (scsi_result ?  "status: TASK SET FULL" :

						    "report: host busy"));

		if (tsf) {

			/* queued_arr full so respond in same thread */

			cmnd->result = scsi_result;

			cmnd->scsi_done(cmnd);

			/* As scsi_done() is called "inline" must return 0 */

			return 0;

		} else

		if (scsi_result)

			goto respond_in_thread;

		else

			return SCSI_MLQUEUE_HOST_BUSY;

	}

	__set_bit(k, queued_in_use_bm);
@@ -3117,12 +3110,18 @@ schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip, 
		else

			tasklet_schedule(sqcp->tletp);

	}

	if (tsf && (SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts))

	if ((SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts) &&

	    (scsi_result == device_qfull_result))

		sdev_printk(KERN_INFO, sdp,

			    "%s: num_in_q=%d +1, %s%s\n", __func__,

			    num_in_q, (inject ? "<inject> " : ""),

			    "status: TASK SET FULL");

	return 0;



respond_in_thread:	/* call back to mid-layer using invocation thread */

	cmnd->result = scsi_result;

	cmnd->scsi_done(cmnd);

	return 0;

}



/* Note: The following macros create attribute files in the