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[5.4,006/203] IB/hfi1: Dont cancel unused work item

Message ID 20200116231745.609284790@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Jan. 16, 2020, 11:15 p.m. UTC 
From: Kaike Wan <kaike.wan@intel.com>

commit ca9033ba69c7e3477f207df69867b2ea969197c8 upstream.

In the iowait structure, two iowait_work entries were included to queue a
given object: one for normal IB operations, and the other for TID RDMA
operations. For non-TID RDMA operations, the iowait_work structure for TID
RDMA is initialized to contain a NULL function (not used). When the QP is
reset, the function iowait_cancel_work will be called to cancel any
pending work. The problem is that this function will call
cancel_work_sync() for both iowait_work entries, even though the one for
TID RDMA is not used at all. Eventually, the call cascades to
__flush_work(), wherein a WARN_ON will be triggered due to the fact that
work->func is NULL.

The WARN_ON was introduced in commit 4d43d395fed1 ("workqueue: Try to
catch flush_work() without INIT_WORK().")

This patch fixes the issue by making sure that a work function is present
for TID RDMA before calling cancel_work_sync in iowait_cancel_work.

Fixes: 4d43d395fed1 ("workqueue: Try to catch flush_work() without INIT_WORK().")
Fixes: 5da0fc9dbf89 ("IB/hfi1: Prepare resource waits for dual leg")
Link: https://lore.kernel.org/r/20191219211941.58387.39883.stgit@awfm-01.aw.intel.com
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/hw/hfi1/iowait.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/infiniband/hw/hfi1/iowait.c
+++ b/drivers/infiniband/hw/hfi1/iowait.c
@@ -81,7 +81,9 @@  void iowait_init(struct iowait *wait, u3
 void iowait_cancel_work(struct iowait *w)
 {
 	cancel_work_sync(&iowait_get_ib_work(w)->iowork);
-	cancel_work_sync(&iowait_get_tid_work(w)->iowork);
+	/* Make sure that the iowork for TID RDMA is used */
+	if (iowait_get_tid_work(w)->iowork.func)
+		cancel_work_sync(&iowait_get_tid_work(w)->iowork);
 }
 
 /**