Although the power management code never calls the system-wide and runtime
suspend callbacks concurrently, runtime power state changes can happen
while the system is being suspended or resumed. See also the dpm_suspend()
and dpm_resume() calls in hibernation_snapshot(). Make sure the sd driver
supports this. This patch avoids that the following call trace is reported
during system-wide suspend:
WARNING: CPU: 0 PID: 701 at drivers/scsi/scsi_lib.c:3047 scsi_device_quiesce+0x4b/0xd0
Workqueue: events_unbound async_run_entry_fn
RIP: 0010:scsi_device_quiesce+0x4b/0xd0
Call Trace:
scsi_bus_suspend_common+0x71/0xe0
scsi_bus_freeze+0x15/0x20
dpm_run_callback+0x88/0x360
__device_suspend+0x1c4/0x840
async_suspend+0x1f/0xb0
async_run_entry_fn+0x6e/0x2c0
process_one_work+0x4ae/0xa20
worker_thread+0x63/0x5a0
kthread+0x1cf/0x1f0
ret_from_fork+0x24/0x30
Fixes: cd84a62e0078 ("block, scsi: Change the preempt-only flag into a counter")
Cc: Lee Duncan <lduncan@xxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/scsi_lib.c | 16 +++++-----------
include/scsi/scsi_device.h | 1 -
2 files changed, 5 insertions(+), 12 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 62348412ed1b..3106e910e766 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -3040,13 +3040,11 @@ scsi_device_quiesce(struct scsi_device *sdev)
int err;
/*
- * It is allowed to call scsi_device_quiesce() multiple times from
- * the same context but concurrent scsi_device_quiesce() calls are
- * not allowed.
+ * Since all scsi_device_quiesce() and scsi_device_resume() calls
+ * are serialized it is safe to check the device state without holding
+ * the SCSI device state mutex.
*/
- WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
-
- if (sdev->quiesced_by == current)
+ if (sdev->sdev_state == SDEV_QUIESCE)
return 0;
blk_set_pm_only(q);
@@ -3063,9 +3061,7 @@ scsi_device_quiesce(struct scsi_device *sdev)
mutex_lock(&sdev->state_mutex);
err = scsi_device_set_state(sdev, SDEV_QUIESCE);
- if (err == 0)
- sdev->quiesced_by = current;
- else
+ if (err)
blk_clear_pm_only(q);
mutex_unlock(&sdev->state_mutex);
@@ -3089,8 +3085,6 @@ void scsi_device_resume(struct scsi_device *sdev)
* device deleted during suspend)
*/
mutex_lock(&sdev->state_mutex);
- WARN_ON_ONCE(!sdev->quiesced_by);
- sdev->quiesced_by = NULL;
blk_clear_pm_only(sdev->request_queue);
if (sdev->sdev_state == SDEV_QUIESCE)
scsi_device_set_state(sdev, SDEV_RUNNING);
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 202f4d6a4342..ef86c8adc5d5 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -226,7 +226,6 @@ struct scsi_device {
unsigned char access_state;
struct mutex state_mutex;
enum scsi_device_state sdev_state;
- struct task_struct *quiesced_by;
unsigned long sdev_data[0];
} __attribute__((aligned(sizeof(unsigned long))));
--
2.19.1.568.g152ad8e336-goog
