Hello James,
Please consider this patch for inclusion in kernel 3.9.
Thanks,
Bart.
On 01/09/13 02:25, Chanho Min wrote:
Is there any progress in this patch?
Oops is still occurred from a torn down device due to this cause.
We look forward to this patch is applied to mainline ASAP.
Thanks
Chanho Min
-----Original Message-----
From: Bart Van Assche [mailto:bvanassche@xxxxxxx]
Sent: Friday, December 07, 2012 12:53 AM
To: undisclosed-recipients:
Cc: linux-scsi; James Bottomley; Mike Christie; Tejun Heo; Chanho Min; Jens Axboe
Subject: [PATCH v7 1/9] Fix race between starved list processing and device removal
Avoid that the sdev reference count can drop to zero before
a queue is run by scsi_run_queue().
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Reported-and-tested-by: Chanho Min <chanho.min@xxxxxxx>
Reference: http://lkml.org/lkml/2012/8/2/96
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Reviewed-by: Mike Christie <michaelc@xxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 16 +++++++++++-----
drivers/scsi/scsi_sysfs.c | 14 +++++++++++++-
2 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f1bf5af..5c67339 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -452,11 +452,17 @@ static void scsi_run_queue(struct request_queue *q)
continue;
}
- spin_unlock(shost->host_lock);
- spin_lock(sdev->request_queue->queue_lock);
- __blk_run_queue(sdev->request_queue);
- spin_unlock(sdev->request_queue->queue_lock);
- spin_lock(shost->host_lock);
+ /*
+ * Obtain a reference before unlocking the host_lock such that
+ * the sdev can't disappear before blk_run_queue() is invoked.
+ */
+ get_device(&sdev->sdev_gendev);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ blk_run_queue(sdev->request_queue);
+ put_device(&sdev->sdev_gendev);
+
+ spin_lock_irqsave(shost->host_lock, flags);
}
/* put any unprocessed entries back */
list_splice(&starved_list, &shost->starved_list);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index ce5224c..2ff7ba5 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -348,7 +348,6 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
starget->reap_ref++;
list_del(&sdev->siblings);
list_del(&sdev->same_target_siblings);
- list_del(&sdev->starved_entry);
spin_unlock_irqrestore(sdev->host->host_lock, flags);
cancel_work_sync(&sdev->event_work);
@@ -956,6 +955,8 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
void __scsi_remove_device(struct scsi_device *sdev)
{
struct device *dev = &sdev->sdev_gendev;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
if (sdev->is_visible) {
if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
@@ -977,6 +978,17 @@ void __scsi_remove_device(struct scsi_device *sdev)
blk_cleanup_queue(sdev->request_queue);
cancel_work_sync(&sdev->requeue_work);
+ /*
+ * Remove a SCSI device from the starved list after blk_cleanup_queue()
+ * finished such that scsi_request_fn() can't add it back to that list.
+ * Also remove an sdev from the starved list before invoking
+ * put_device() such that get_device() is guaranteed to succeed for an
+ * sdev present on the starved list.
+ */
+ spin_lock_irqsave(shost->host_lock, flags);
+ list_del(&sdev->starved_entry);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
--
1.7.10.4
--
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