ChangeSet 1.2181.22.21, 2005/03/29 17:20:00-06:00, [EMAIL PROTECTED]
[PATCH] fix fc class work queue usage
According to this article http://lwn.net/Articles/125930/, "When
cancel_delayed_work() returns zero, it means that the delayed
work request was fired off before the call; it might, in fact,
be running on another CPU when the cancel attempt is made".
If it is successful, it returns a nonzero value. Tracing
through cancel_delayed_work's timer usage would seem to confirm
this. The fc class today though performs a flush_scheduled_work,
when the return value is nonzero instead of zero.
Also it appears the fc class will use flush_scheduled_work to
flush the work from the shost_work_q when it should be using
flush_workqueue(shost->work_q) (flush_scheduled_work() only
flushes the default, keventd_wq, work queue).
The attached patch adds a scsi_flush_work function for
scsi_transport_fc to use and it fixes the cancel_delayed_work()
test to detect when to flush the work queues correctly (it
also only calls cancel_delayed_work when the work is queued
as delayed (scan_work is not delayed).
Signed-off-by: Mike Chrisite <[EMAIL PROTECTED]>
Signed-off-by: James Bottomley <[EMAIL PROTECTED]>
drivers/scsi/hosts.c | 17 +++++++++++++++++
drivers/scsi/scsi_transport_fc.c | 8 +++++---
include/scsi/scsi_host.h | 1 +
3 files changed, 23 insertions(+), 3 deletions(-)
diff -Nru a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
--- a/drivers/scsi/hosts.c 2005-03-30 16:22:54 -08:00
+++ b/drivers/scsi/hosts.c 2005-03-30 16:22:54 -08:00
@@ -443,3 +443,20 @@
}
EXPORT_SYMBOL_GPL(scsi_queue_work);
+/**
+ * scsi_flush_work - Flush a Scsi_Host's workqueue.
+ * @shost: Pointer to Scsi_Host.
+ **/
+void scsi_flush_work(struct Scsi_Host *shost)
+{
+ if (!shost->work_q) {
+ printk(KERN_ERR
+ "ERROR: Scsi host '%s' attempted to flush scsi-work, "
+ "when no workqueue created.\n", shost->hostt->name);
+ dump_stack();
+ return;
+ }
+
+ flush_workqueue(shost->work_q);
+}
+EXPORT_SYMBOL_GPL(scsi_flush_work);
diff -Nru a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
--- a/drivers/scsi/scsi_transport_fc.c 2005-03-30 16:22:54 -08:00
+++ b/drivers/scsi/scsi_transport_fc.c 2005-03-30 16:22:54 -08:00
@@ -1375,12 +1375,14 @@
static void
fc_rport_tgt_remove(struct fc_rport *rport)
{
+ struct Scsi_Host *shost = rport_to_shost(rport);
+
scsi_target_unblock(&rport->dev);
/* Stop anything on the workq */
- if (cancel_delayed_work(&rport->dev_loss_work) ||
- cancel_delayed_work(&rport->scan_work))
+ if (!cancel_delayed_work(&rport->dev_loss_work))
flush_scheduled_work();
+ scsi_flush_work(shost);
scsi_remove_target(&rport->dev);
}
@@ -1625,7 +1627,7 @@
* failure as the state machine state change will validate the
* transaction.
*/
- if (cancel_delayed_work(work))
+ if (!cancel_delayed_work(work))
flush_scheduled_work();
if (rport->port_state == FC_PORTSTATE_OFFLINE)
diff -Nru a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
--- a/include/scsi/scsi_host.h 2005-03-30 16:22:54 -08:00
+++ b/include/scsi/scsi_host.h 2005-03-30 16:22:54 -08:00
@@ -590,6 +590,7 @@
}
extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
+extern void scsi_flush_work(struct Scsi_Host *);
extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
-
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