From cd62b7dae245dd3bb3a21eaadcf01d93ec4fcc7c Mon Sep 17 00:00:00 2001 From: Douglas Gilbert Date: Tue, 5 Aug 2014 12:20:46 +0200 Subject: [PATCH] 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: Douglas Gilbert Reviewed-by: Martin K. Petersen Signed-off-by: Christoph Hellwig --- drivers/scsi/scsi_debug.c | 67 +++++++++++++++++++-------------------- 1 file changed, 33 insertions(+), 34 deletions(-) diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 07d224aa9b47..693f2fa327ee 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -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 ? " " : ""), - (tsf ? "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 + "%s: max_queue=%d exceeded, %s\n", + __func__, scsi_debug_max_queue, + (scsi_result ? "status: TASK SET FULL" : + "report: host busy")); + 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 ? " " : ""), "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 -- 2.20.1