korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-24 04:34:08 +08:00
Code Issues Packages Projects Releases Wiki Activity

scsi: sd: Revert "Rework asynchronous resume support"

Browse Source 
Although commit 88f1669019 ("scsi: sd: Rework asynchronous resume support")
eliminates a 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@ramsan.of.borg/).

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).

Link: https://lore.kernel.org/r/20220816172638.538734-1-bvanassche@acm.org
Fixes: 88f1669019 ("scsi: sd: Rework asynchronous resume support")
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: gzhqyz@gmail.com
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: gzhqyz@gmail.com
Reported-and-tested-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: John Garry <john.garry@huawei.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bart Van Assche 2022-08-16 10:26:38 -07:00 committed by Martin K. Petersen
parent fac8e558da
commit 785538bfdd
2 changed files with 18 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

84
drivers/scsi/sd.c
View File

@ -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)

5
drivers/scsi/sd.h
View File

@ -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)