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 <ming.lei@xxxxxxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: John Garry <john.garry@xxxxxxxxxx> Cc: ericspero@xxxxxxxxxx Cc: jason600.groome@xxxxxxxxx Tested-by: jason600.groome@xxxxxxxxx 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 <bvanassche@xxxxxxx> --- 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)
