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> --- 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)
