--- /dev/null
+From 785538bfdd682c8e962341d585f9b88262a0475e Mon Sep 17 00:00:00 2001
+From: Bart Van Assche <bvanassche@acm.org>
+Date: Tue, 16 Aug 2022 10:26:38 -0700
+Subject: scsi: sd: Revert "Rework asynchronous resume support"
+
+From: Bart Van Assche <bvanassche@acm.org>
+
+commit 785538bfdd682c8e962341d585f9b88262a0475e upstream.
+
+Although commit 88f1669019bd ("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: 88f1669019bd ("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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/scsi/sd.c | 84 +++++++++++-------------------------------------------
+ drivers/scsi/sd.h | 5 ---
+ 2 files changed, 18 insertions(+), 71 deletions(-)
+
+--- a/drivers/scsi/sd.c
++++ b/drivers/scsi/sd.c
+@@ -105,7 +105,6 @@ static void sd_config_discard(struct scs
+ 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 *);
+@@ -3404,7 +3403,6 @@ 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)
+@@ -3565,69 +3563,12 @@ static void scsi_disk_release(struct 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 */
+@@ -3638,10 +3579,23 @@ static int sd_start_stop_device(struct s
+ 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;
+ }
+
+ /*
+@@ -3668,8 +3622,6 @@ static void sd_shutdown(struct device *d
+ 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)
+--- a/drivers/scsi/sd.h
++++ b/drivers/scsi/sd.h
+@@ -130,11 +130,6 @@ 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)
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
