From patchwork Mon Feb 1 23:30:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Gilbert X-Patchwork-Id: 374435 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9829C433E0 for ; Mon, 1 Feb 2021 23:31:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8AFB764D90 for ; Mon, 1 Feb 2021 23:31:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229629AbhBAXbP (ORCPT ); Mon, 1 Feb 2021 18:31:15 -0500 Received: from smtp.infotech.no ([82.134.31.41]:48784 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229593AbhBAXbK (ORCPT ); Mon, 1 Feb 2021 18:31:10 -0500 Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id C7A7020418D; Tue, 2 Feb 2021 00:30:25 +0100 (CET) X-Virus-Scanned: by amavisd-new-2.6.6 (20110518) (Debian) at infotech.no Received: from smtp.infotech.no ([127.0.0.1]) by localhost (smtp.infotech.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id aW6GXK8b6cK7; Tue, 2 Feb 2021 00:30:23 +0100 (CET) Received: from xtwo70.bingwo.ca (host-104-157-204-209.dyn.295.ca [104.157.204.209]) by smtp.infotech.no (Postfix) with ESMTPA id CE3572042A6; Tue, 2 Feb 2021 00:30:22 +0100 (CET) From: Douglas Gilbert To: linux-scsi@vger.kernel.org Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, hare@suse.de, kashyap.desai@broadcom.com Subject: [PATCH] scsi_debug: add new defer_type for mq_poll Date: Mon, 1 Feb 2021 18:30:20 -0500 Message-Id: <20210201233020.4773-1-dgilbert@interlog.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Add a new sdeb_defer_type enumeration: SDEB_DEFER_POLL for requests that have REQ_HIPRI set in cmd_flags field. It is expected that these requests will be polled via the mq_poll entry point which is driven by calls to blk_poll() in the block layer. Therefore timer events are not 'wired up' in the normal fashion. There are still cases with short delays (e.g. < 10 microseconds) where by the time the command reponse processing occurs, the delay is already exceeded in which case the code calls scsi_done() directly. In such cases there is no window for mq_poll() to be called. This patch is against the 5.12/scsi-staging branch which includes a98d6bdf181eb71bf4686666eaf47c642a061642 scsi_debug : iouring iopoll support which it alters. So this patch is a fix of that patch which fails in testing. Signed-off-by: Douglas Gilbert --- drivers/scsi/scsi_debug.c | 106 +++++++++++++++++++++++++++----------- 1 file changed, 75 insertions(+), 31 deletions(-) diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 746eec521f79..d030c270796b 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -322,17 +322,19 @@ struct sdeb_store_info { container_of(d, struct sdebug_host_info, dev) enum sdeb_defer_type {SDEB_DEFER_NONE = 0, SDEB_DEFER_HRT = 1, - SDEB_DEFER_WQ = 2}; + SDEB_DEFER_WQ = 2, SDEB_DEFER_POLL = 3}; struct sdebug_defer { struct hrtimer hrt; struct execute_work ew; + ktime_t cmpl_ts;/* time since boot to complete this cmd */ int sqa_idx; /* index of sdebug_queue array */ int qc_idx; /* index of sdebug_queued_cmd array within sqa_idx */ int hc_idx; /* hostwide tag index */ int issuing_cpu; bool init_hrt; bool init_wq; + bool init_poll; bool aborted; /* true when blk_abort_request() already called */ enum sdeb_defer_type defer_t; }; @@ -5517,40 +5519,62 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip, kt -= d; } } - if (!sd_dp->init_hrt) { - sd_dp->init_hrt = true; - sqcp->sd_dp = sd_dp; - hrtimer_init(&sd_dp->hrt, CLOCK_MONOTONIC, - HRTIMER_MODE_REL_PINNED); - sd_dp->hrt.function = sdebug_q_cmd_hrt_complete; - sd_dp->sqa_idx = sqp - sdebug_q_arr; - sd_dp->qc_idx = k; + sd_dp->cmpl_ts = ktime_add(ns_to_ktime(ns_from_boot), kt); + if (cmnd->request->cmd_flags & REQ_HIPRI) { + if (!sd_dp->init_poll) { + sd_dp->init_poll = true; + sqcp->sd_dp = sd_dp; + sd_dp->sqa_idx = sqp - sdebug_q_arr; + sd_dp->qc_idx = k; + } + sd_dp->defer_t = SDEB_DEFER_POLL; + } else { + if (!sd_dp->init_hrt) { + sd_dp->init_hrt = true; + sqcp->sd_dp = sd_dp; + hrtimer_init(&sd_dp->hrt, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_PINNED); + sd_dp->hrt.function = sdebug_q_cmd_hrt_complete; + sd_dp->sqa_idx = sqp - sdebug_q_arr; + sd_dp->qc_idx = k; + } + sd_dp->defer_t = SDEB_DEFER_HRT; + /* schedule the invocation of scsi_done() for a later time */ + hrtimer_start(&sd_dp->hrt, kt, HRTIMER_MODE_REL_PINNED); } if (sdebug_statistics) sd_dp->issuing_cpu = raw_smp_processor_id(); - sd_dp->defer_t = SDEB_DEFER_HRT; - /* schedule the invocation of scsi_done() for a later time */ - hrtimer_start(&sd_dp->hrt, kt, HRTIMER_MODE_REL_PINNED); } else { /* jdelay < 0, use work queue */ - if (!sd_dp->init_wq) { - sd_dp->init_wq = true; - sqcp->sd_dp = sd_dp; - sd_dp->sqa_idx = sqp - sdebug_q_arr; - sd_dp->qc_idx = k; - INIT_WORK(&sd_dp->ew.work, sdebug_q_cmd_wq_complete); - } - if (sdebug_statistics) - sd_dp->issuing_cpu = raw_smp_processor_id(); - sd_dp->defer_t = SDEB_DEFER_WQ; if (unlikely((sdebug_opts & SDEBUG_OPT_CMD_ABORT) && atomic_read(&sdeb_inject_pending))) sd_dp->aborted = true; - schedule_work(&sd_dp->ew.work); - if (unlikely((sdebug_opts & SDEBUG_OPT_CMD_ABORT) && - atomic_read(&sdeb_inject_pending))) { + sd_dp->cmpl_ts = ns_to_ktime(ns_from_boot); + if (cmnd->request->cmd_flags & REQ_HIPRI) { + if (!sd_dp->init_poll) { + sd_dp->init_poll = true; + sqcp->sd_dp = sd_dp; + sd_dp->sqa_idx = sqp - sdebug_q_arr; + sd_dp->qc_idx = k; + } + sd_dp->defer_t = SDEB_DEFER_POLL; + } else { + if (!sd_dp->init_wq) { + sd_dp->init_wq = true; + sqcp->sd_dp = sd_dp; + sd_dp->sqa_idx = sqp - sdebug_q_arr; + sd_dp->qc_idx = k; + INIT_WORK(&sd_dp->ew.work, sdebug_q_cmd_wq_complete); + } + sd_dp->defer_t = SDEB_DEFER_WQ; + schedule_work(&sd_dp->ew.work); + } + if (sdebug_statistics) + sd_dp->issuing_cpu = raw_smp_processor_id(); + if (unlikely(sd_dp->aborted)) { sdev_printk(KERN_INFO, sdp, "abort request tag %d\n", cmnd->request->tag); blk_abort_request(cmnd->request); atomic_set(&sdeb_inject_pending, 0); + sd_dp->aborted = false; } } if (unlikely((SDEBUG_OPT_Q_NOISE & sdebug_opts) && scsi_result == device_qfull_result)) @@ -7246,30 +7270,47 @@ static int sdebug_map_queues(struct Scsi_Host *shost) static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) { - int qc_idx; + bool first = true; int retiring = 0; + int num_entries = 0; + unsigned int qc_idx; unsigned long iflags; + ktime_t kt_from_boot = ktime_get_boottime(); struct sdebug_queue *sqp; struct sdebug_queued_cmd *sqcp; struct scsi_cmnd *scp; struct sdebug_dev_info *devip; - int num_entries = 0; sqp = sdebug_q_arr + queue_num; do { spin_lock_irqsave(&sqp->qc_lock, iflags); - qc_idx = find_first_bit(sqp->in_use_bm, sdebug_max_queue); - if (unlikely((qc_idx < 0) || (qc_idx >= sdebug_max_queue))) + if (first) { + qc_idx = find_first_bit(sqp->in_use_bm, sdebug_max_queue); + first = false; + } else { + qc_idx = find_next_bit(sqp->in_use_bm, sdebug_max_queue, qc_idx + 1); + } + if (unlikely(qc_idx >= sdebug_max_queue)) goto out; sqcp = &sqp->qc_arr[qc_idx]; scp = sqcp->a_cmnd; if (unlikely(scp == NULL)) { - pr_err("scp is NULL, queue_num=%d, qc_idx=%d from %s\n", + pr_err("scp is NULL, queue_num=%d, qc_idx=%u from %s\n", queue_num, qc_idx, __func__); goto out; } + if (sqcp->sd_dp->defer_t == SDEB_DEFER_POLL) { + if (kt_from_boot < sqcp->sd_dp->cmpl_ts) { + spin_unlock_irqrestore(&sqp->qc_lock, iflags); + goto around; + } + + } else { /* ignoring non REQ_HIPRI requests */ + spin_unlock_irqrestore(&sqp->qc_lock, iflags); + goto around; + } devip = (struct sdebug_dev_info *)scp->device->hostdata; if (likely(devip)) atomic_dec(&devip->num_in_q); @@ -7280,7 +7321,7 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) sqcp->a_cmnd = NULL; if (unlikely(!test_and_clear_bit(qc_idx, sqp->in_use_bm))) { - pr_err("Unexpected completion sqp %p queue_num=%d qc_idx=%d from %s\n", + pr_err("Unexpected completion sqp %p queue_num=%d qc_idx=%u from %s\n", sqp, queue_num, qc_idx, __func__); goto out; } @@ -7302,6 +7343,9 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) spin_unlock_irqrestore(&sqp->qc_lock, iflags); scp->scsi_done(scp); /* callback to mid level */ num_entries++; +around: + if (qc_idx + 1 == sdebug_max_queue) + return num_entries; } while (1); out: