From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9BE6C43334 for ; Tue, 19 Jul 2022 09:26:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237186AbiGSJ01 (ORCPT ); Tue, 19 Jul 2022 05:26:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237022AbiGSJ0X (ORCPT ); Tue, 19 Jul 2022 05:26:23 -0400 Received: from albert.telenet-ops.be (albert.telenet-ops.be [IPv6:2a02:1800:110:4::f00:1a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 797B31FCD5 for ; Tue, 19 Jul 2022 02:26:21 -0700 (PDT) Received: from ramsan.of.borg ([84.195.186.194]) by albert.telenet-ops.be with bizsmtp id wxSG2700S4C55Sk06xSGow; Tue, 19 Jul 2022 11:26:18 +0200 Received: from geert (helo=localhost) by ramsan.of.borg with local-esmtp (Exim 4.93) (envelope-from ) id 1oDjUZ-004Dzd-3y; Tue, 19 Jul 2022 11:26:11 +0200 Date: Tue, 19 Jul 2022 11:26:06 +0200 (CEST) From: Geert Uytterhoeven X-X-Sender: geert@ramsan.of.borg To: Bart Van Assche cc: "Martin K . Petersen" , Jaegeuk Kim , linux-scsi@vger.kernel.org, Ming Lei , Hannes Reinecke , John Garry , ericspero@icloud.com, jason600.groome@gmail.com, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] scsi: sd: Rework asynchronous resume support In-Reply-To: <20220630195703.10155-3-bvanassche@acm.org> Message-ID: References: <20220630195703.10155-1-bvanassche@acm.org> <20220630195703.10155-3-bvanassche@acm.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hoi Bart, On Thu, 30 Jun 2022, Bart Van Assche wrote: > For some technologies, e.g. an ATA bus, resuming can take multiple > seconds. Waiting for resume to finish can cause a very noticeable delay. > Hence this patch that restores the behavior from before patch "scsi: > core: pm: Rely on the device driver core for async power management" for > most SCSI devices. > > This patch introduces a behavior change: if the START command fails, do > not consider this as a SCSI disk resume failure. > > Cc: Ming Lei > Cc: Hannes Reinecke > Cc: John Garry > Cc: ericspero@icloud.com > Cc: jason600.groome@gmail.com > Tested-by: jason600.groome@gmail.com > Link: https://bugzilla.kernel.org/show_bug.cgi?id=215880 > Fixes: a19a93e4c6a9 ("scsi: core: pm: Rely on the device driver core for async power management") > Signed-off-by: Bart Van Assche Thanks for your patch, which is now commit 88f1669019bd62b3 ("scsi: sd: Rework asynchronous resume support") in scsi/for-next. On the Salvator-XS development board[1] with a SATA hard drive connected, accessing the hard drive after resume from s2idle hangs. I have bisected this to the aformentioned commit, and reverting this commit fixes the issue. [1] arch/arm64/boot/dts/renesas/r8a77951-salvator-xs.dts > --- > drivers/scsi/sd.c | 84 +++++++++++++++++++++++++++++++++++++---------- > drivers/scsi/sd.h | 5 +++ > 2 files changed, 71 insertions(+), 18 deletions(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 895b56c8f25e..84696b3652ee 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -103,6 +103,7 @@ static void sd_config_discard(struct scsi_disk *, unsigned int); > static void sd_config_write_same(struct scsi_disk *); > static int sd_revalidate_disk(struct gendisk *); > static void sd_unlock_native_capacity(struct gendisk *disk); > +static void sd_start_done_work(struct work_struct *work); > static int sd_probe(struct device *); > static int sd_remove(struct device *); > static void sd_shutdown(struct device *); > @@ -3463,6 +3464,7 @@ static int sd_probe(struct device *dev) > sdkp->max_retries = SD_MAX_RETRIES; > atomic_set(&sdkp->openers, 0); > atomic_set(&sdkp->device->ioerr_cnt, 0); > + INIT_WORK(&sdkp->start_done_work, sd_start_done_work); > > if (!sdp->request_queue->rq_timeout) { > if (sdp->type != TYPE_MOD) > @@ -3585,12 +3587,69 @@ static void scsi_disk_release(struct device *dev) > kfree(sdkp); > } > > +/* Process sense data after a START command finished. */ > +static void sd_start_done_work(struct work_struct *work) > +{ > + struct scsi_disk *sdkp = container_of(work, typeof(*sdkp), > + start_done_work); > + struct scsi_sense_hdr sshdr; > + int res = sdkp->start_result; > + > + if (res == 0) > + return; > + > + sd_print_result(sdkp, "Start/Stop Unit failed", res); > + > + if (res < 0) > + return; > + > + if (scsi_normalize_sense(sdkp->start_sense_buffer, > + sdkp->start_sense_len, &sshdr)) > + sd_print_sense_hdr(sdkp, &sshdr); > +} > + > +/* A START command finished. May be called from interrupt context. */ > +static void sd_start_done(struct request *req, blk_status_t status) > +{ > + const struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req); > + struct scsi_disk *sdkp = scsi_disk(req->q->disk); > + > + sdkp->start_result = scmd->result; > + WARN_ON_ONCE(scmd->sense_len > SCSI_SENSE_BUFFERSIZE); > + sdkp->start_sense_len = scmd->sense_len; > + memcpy(sdkp->start_sense_buffer, scmd->sense_buffer, > + ARRAY_SIZE(sdkp->start_sense_buffer)); > + WARN_ON_ONCE(!schedule_work(&sdkp->start_done_work)); > +} > + > +/* Submit a START command asynchronously. */ > +static int sd_submit_start(struct scsi_disk *sdkp, u8 cmd[], u8 cmd_len) > +{ > + struct scsi_device *sdev = sdkp->device; > + struct request_queue *q = sdev->request_queue; > + struct request *req; > + struct scsi_cmnd *scmd; > + > + req = scsi_alloc_request(q, REQ_OP_DRV_IN, BLK_MQ_REQ_PM); > + if (IS_ERR(req)) > + return PTR_ERR(req); > + > + scmd = blk_mq_rq_to_pdu(req); > + scmd->cmd_len = cmd_len; > + memcpy(scmd->cmnd, cmd, cmd_len); > + scmd->allowed = sdkp->max_retries; > + req->timeout = SD_TIMEOUT; > + req->rq_flags |= RQF_PM | RQF_QUIET; > + req->end_io = sd_start_done; > + blk_execute_rq_nowait(req, /*at_head=*/true); > + > + return 0; > +} > + > static int sd_start_stop_device(struct scsi_disk *sdkp, int start) > { > unsigned char cmd[6] = { START_STOP }; /* START_VALID */ > - struct scsi_sense_hdr sshdr; > struct scsi_device *sdp = sdkp->device; > - int res; > > if (start) > cmd[4] |= 1; /* START */ > @@ -3601,23 +3660,10 @@ static int sd_start_stop_device(struct scsi_disk *sdkp, int start) > if (!scsi_device_online(sdp)) > return -ENODEV; > > - res = scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL, &sshdr, > - SD_TIMEOUT, sdkp->max_retries, 0, RQF_PM, NULL); > - if (res) { > - sd_print_result(sdkp, "Start/Stop Unit failed", res); > - if (res > 0 && scsi_sense_valid(&sshdr)) { > - sd_print_sense_hdr(sdkp, &sshdr); > - /* 0x3a is medium not present */ > - if (sshdr.asc == 0x3a) > - res = 0; > - } > - } > + /* Wait until processing of sense data has finished. */ > + flush_work(&sdkp->start_done_work); > > - /* SCSI error codes must not go to the generic layer */ > - if (res) > - return -EIO; > - > - return 0; > + return sd_submit_start(sdkp, cmd, sizeof(cmd)); > } > > /* > @@ -3644,6 +3690,8 @@ static void sd_shutdown(struct device *dev) > sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n"); > sd_start_stop_device(sdkp, 0); > } > + > + flush_work(&sdkp->start_done_work); > } > > static int sd_suspend_common(struct device *dev, bool ignore_stop_errors) > diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h > index 5eea762f84d1..b89187761d61 100644 > --- a/drivers/scsi/sd.h > +++ b/drivers/scsi/sd.h > @@ -150,6 +150,11 @@ struct scsi_disk { > unsigned urswrz : 1; > unsigned security : 1; > unsigned ignore_medium_access_errors : 1; > + > + int start_result; > + u32 start_sense_len; > + u8 start_sense_buffer[SCSI_SENSE_BUFFERSIZE]; > + struct work_struct start_done_work; > }; > #define to_scsi_disk(obj) container_of(obj, struct scsi_disk, disk_dev) > Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds