[PATCH v2 2/2] ib_srp: Fix a deadlock

[Bart Van Assche <bvanassche@acm.org>]

Remove the flush_workqueue(system_long_wq) call since flushing
system_long_wq is deadlock-prone and since that call is redundant.

Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Fixes: ef6c49d87c34 ("IB/srp: Eliminate state SRP_TARGET_DEAD")
Reported-by: syzbot+831661966588c802aae9@syzkaller.appspotmail.com
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index e174e853f8a4..285b766e4e70 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -4047,9 +4047,11 @@ static void srp_remove_one(struct ib_device *device, void *client_data)
 		spin_unlock(&host->target_lock);
 
 		/*
-		 * Wait for tl_err and target port removal tasks.
+		 * srp_queue_remove_work() queues a call to
+		 * srp_remove_target(). The latter function cancels
+		 * target->tl_err_work so waiting for the remove works to
+		 * finish is sufficient.
 		 */
-		flush_workqueue(system_long_wq);
 		flush_workqueue(srp_remove_wq);
 
 		kfree(host);