[PATCH 4.9 21/28] soc/fsl/qbman: fix issue in qman_delete_cgr_safe()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Madalin Bucur <madalin.bu...@nxp.com>


[ Upstream commit 96f413f47677366e0ae03797409bfcc4151dbf9e ]

The wait_for_completion() call in qman_delete_cgr_safe()
was triggering a scheduling while atomic bug, replacing the
kthread with a smp_call_function_single() call to fix it.

Signed-off-by: Madalin Bucur <madalin.bu...@nxp.com>
Signed-off-by: Roy Pledge <roy.ple...@nxp.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/soc/fsl/qbman/qman.c |   28 +++++-----------------------
 1 file changed, 5 insertions(+), 23 deletions(-)

--- a/drivers/soc/fsl/qbman/qman.c
+++ b/drivers/soc/fsl/qbman/qman.c
@@ -2429,39 +2429,21 @@ struct cgr_comp {
        struct completion completion;
 };
 
-static int qman_delete_cgr_thread(void *p)
+static void qman_delete_cgr_smp_call(void *p)
 {
-       struct cgr_comp *cgr_comp = (struct cgr_comp *)p;
-       int ret;
-
-       ret = qman_delete_cgr(cgr_comp->cgr);
-       complete(&cgr_comp->completion);
-
-       return ret;
+       qman_delete_cgr((struct qman_cgr *)p);
 }
 
 void qman_delete_cgr_safe(struct qman_cgr *cgr)
 {
-       struct task_struct *thread;
-       struct cgr_comp cgr_comp;
-
        preempt_disable();
        if (qman_cgr_cpus[cgr->cgrid] != smp_processor_id()) {
-               init_completion(&cgr_comp.completion);
-               cgr_comp.cgr = cgr;
-               thread = kthread_create(qman_delete_cgr_thread, &cgr_comp,
-                                       "cgr_del");
-
-               if (IS_ERR(thread))
-                       goto out;
-
-               kthread_bind(thread, qman_cgr_cpus[cgr->cgrid]);
-               wake_up_process(thread);
-               wait_for_completion(&cgr_comp.completion);
+               smp_call_function_single(qman_cgr_cpus[cgr->cgrid],
+                                        qman_delete_cgr_smp_call, cgr, true);
                preempt_enable();
                return;
        }
-out:
+
        qman_delete_cgr(cgr);
        preempt_enable();
 }