From 4fa8324461b824eaea9b6695464395710fe20c44 Mon Sep 17 00:00:00 2001 From: Derek Basehore Date: Thu, 11 May 2017 14:34:24 +0200 Subject: [PATCH] scsi: sd: Ignore sync cache failures when not supported Some external hard drives don't support the sync command even though the hard drive has write cache enabled. In this case, upon suspend request, sync cache failures are ignored if the error code in the sense header is ILLEGAL_REQUEST. There's not much we can do for these drives, so we shouldn't fail to suspend for this error case. The drive may stay powered if that's the setup for the port it's plugged into. Signed-off-by: Derek Basehore Signed-off-by: Thierry Escande Reviewed-by: Ewan D. Milne Signed-off-by: Martin K. Petersen --- drivers/scsi/sd.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index de9e2f2ef662..b6bb4e0ce0e3 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1582,17 +1582,21 @@ out: return retval; } -static int sd_sync_cache(struct scsi_disk *sdkp) +static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr) { int retries, res; struct scsi_device *sdp = sdkp->device; const int timeout = sdp->request_queue->rq_timeout * SD_FLUSH_TIMEOUT_MULTIPLIER; - struct scsi_sense_hdr sshdr; + struct scsi_sense_hdr my_sshdr; if (!scsi_device_online(sdp)) return -ENODEV; + /* caller might not be interested in sense, but we need it */ + if (!sshdr) + sshdr = &my_sshdr; + for (retries = 3; retries > 0; --retries) { unsigned char cmd[10] = { 0 }; @@ -1601,7 +1605,7 @@ static int sd_sync_cache(struct scsi_disk *sdkp) * Leave the rest of the command zero to indicate * flush everything. */ - res = scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL, &sshdr, + res = scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL, sshdr, timeout, SD_MAX_RETRIES, 0, RQF_PM, NULL); if (res == 0) break; @@ -1611,11 +1615,12 @@ static int sd_sync_cache(struct scsi_disk *sdkp) sd_print_result(sdkp, "Synchronize Cache(10) failed", res); if (driver_byte(res) & DRIVER_SENSE) - sd_print_sense_hdr(sdkp, &sshdr); + sd_print_sense_hdr(sdkp, sshdr); + /* we need to evaluate the error return */ - if (scsi_sense_valid(&sshdr) && - (sshdr.asc == 0x3a || /* medium not present */ - sshdr.asc == 0x20)) /* invalid command */ + if (scsi_sense_valid(sshdr) && + (sshdr->asc == 0x3a || /* medium not present */ + sshdr->asc == 0x20)) /* invalid command */ /* this is no error here */ return 0; @@ -3459,7 +3464,7 @@ static void sd_shutdown(struct device *dev) if (sdkp->WCE && sdkp->media_present) { sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n"); - sd_sync_cache(sdkp); + sd_sync_cache(sdkp, NULL); } if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) { @@ -3471,6 +3476,7 @@ static void sd_shutdown(struct device *dev) static int sd_suspend_common(struct device *dev, bool ignore_stop_errors) { struct scsi_disk *sdkp = dev_get_drvdata(dev); + struct scsi_sense_hdr sshdr; int ret = 0; if (!sdkp) /* E.g.: runtime suspend following sd_remove() */ @@ -3478,12 +3484,23 @@ static int sd_suspend_common(struct device *dev, bool ignore_stop_errors) if (sdkp->WCE && sdkp->media_present) { sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n"); - ret = sd_sync_cache(sdkp); + ret = sd_sync_cache(sdkp, &sshdr); + if (ret) { /* ignore OFFLINE device */ if (ret == -ENODEV) - ret = 0; - goto done; + return 0; + + if (!scsi_sense_valid(&sshdr) || + sshdr.sense_key != ILLEGAL_REQUEST) + return ret; + + /* + * sshdr.sense_key == ILLEGAL_REQUEST means this drive + * doesn't support sync. There's not much to do and + * suspend shouldn't fail. + */ + ret = 0; } } @@ -3495,7 +3512,6 @@ static int sd_suspend_common(struct device *dev, bool ignore_stop_errors) ret = 0; } -done: return ret; } -- 2.30.2