On 8/16/22 19:26, Bart Van Assche wrote: > Although patch "Rework asynchronous resume support" eliminates the delay > for some ATA disks after resume, it causes resume of ATA disks to fail > on other setups. See also: > * "Resume process hangs for 5-6 seconds starting sometime in 5.16" > (https://bugzilla.kernel.org/show_bug.cgi?id=215880). > * Geert's regression report > (https://lore.kernel.org/linux-scsi/alpine.DEB.2.22.394.2207191125130.1006766@xxxxxxxxxxxxxx/). > > This is what I understand about this issue: > * During resume, ata_port_pm_resume() starts the SCSI error handler. > This changes the SCSI host state into SHOST_RECOVERY and causes > scsi_queue_rq() to return BLK_STS_RESOURCE. > * sd_resume() calls sd_start_stop_device() for ATA devices. That > function in turn calls sd_submit_start() which tries to submit a START > STOP UNIT command. That command can only be submitted after the SCSI > error handler has changed the SCSI host state back to SHOST_RUNNING. > * The SCSI error handler runs on its own thread and calls > schedule_work(&(ap->scsi_rescan_task)). That causes > ata_scsi_dev_rescan() to be called from the context of a kernel > workqueue. That call hangs in blk_mq_get_tag(). I'm not sure why - > maybe because all available tags have been allocated by > sd_submit_start() calls (this is a guess). > > Cc: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx> > Cc: Hannes Reinecke <hare@xxxxxxx> > Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Cc: gzhqyz@xxxxxxxxx > Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Reported-by: gzhqyz@xxxxxxxxx > Fixes: 88f1669019bd ("scsi: sd: Rework asynchronous resume support"; v6.0-rc1~114^2~68) > Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> Reported-and-tested-by: Vlastimil Babka <vbabka@xxxxxxx> > --- > drivers/scsi/sd.c | 84 ++++++++++------------------------------------- > drivers/scsi/sd.h | 5 --- > 2 files changed, 18 insertions(+), 71 deletions(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 8f79fa6318fe..eb76ba055021 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -103,7 +103,6 @@ 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 *); > @@ -3471,7 +3470,6 @@ 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) > @@ -3594,69 +3592,12 @@ 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 */ > @@ -3667,10 +3608,23 @@ static int sd_start_stop_device(struct scsi_disk *sdkp, int start) > if (!scsi_device_online(sdp)) > return -ENODEV; > > - /* Wait until processing of sense data has finished. */ > - flush_work(&sdkp->start_done_work); > + 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; > + } > + } > > - return sd_submit_start(sdkp, cmd, sizeof(cmd)); > + /* SCSI error codes must not go to the generic layer */ > + if (res) > + return -EIO; > + > + return 0; > } > > /* > @@ -3697,8 +3651,6 @@ 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 b89187761d61..5eea762f84d1 100644 > --- a/drivers/scsi/sd.h > +++ b/drivers/scsi/sd.h > @@ -150,11 +150,6 @@ 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) >
