On 10/30/2015 03:09 PM, Bart Van Assche wrote:
When dropping a lock while iterating a list we must restart the search
as other threads could have manipulated the list under us. Without this
we can get stuck in an endless loop.
This is a slightly modified version of a patch from Christoph Hellwig
(see also https://www.spinics.net/lists/linux-scsi/msg89416.html).
Reported-by: Johannes Thumshirn <jthumsh...@suse.de>
Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com>
Cc: Johannes Thumshirn <jthumsh...@suse.de>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: stable <sta...@vger.kernel.org>
---
drivers/scsi/scsi_sysfs.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index b9fb61a..5a183d1 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1158,32 +1158,24 @@ static void __scsi_remove_target(struct scsi_target
*starget)
void scsi_remove_target(struct device *dev)
{
struct Scsi_Host *shost = dev_to_shost(dev->parent);
- struct scsi_target *starget, *last = NULL;
+ struct scsi_target *starget;
unsigned long flags;
- /* remove targets being careful to lookup next entry before
- * deleting the last
- */
+restart:
spin_lock_irqsave(shost->host_lock, flags);
list_for_each_entry(starget, &shost->__targets, siblings) {
if (starget->reaped)
continue;
if (starget->dev.parent == dev || &starget->dev == dev) {
- /* assuming new targets arrive at the end */
kref_get(&starget->reap_ref);
starget->reaped = true;
spin_unlock_irqrestore(shost->host_lock, flags);
- if (last)
- scsi_target_reap(last);
- last = starget;
__scsi_remove_target(starget);
- spin_lock_irqsave(shost->host_lock, flags);
+ scsi_target_reap(starget);
+ goto restart;
}
}
spin_unlock_irqrestore(shost->host_lock, flags);
-
- if (last)
- scsi_target_reap(last);
}
EXPORT_SYMBOL(scsi_remove_target);
(replying to my own e-mail)
Hello Christoph,
Is it OK for you if I mention you as author of this e-mail ?
Thanks,
Bart.
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