Apply the cpumask and cgroup of the initializing task to the created
vhost worker.

Based on Sridhar Samudrala's patch.  Li Zefan spotted a bug in error
path (twice), fixed (twice).

Signed-off-by: Tejun Heo <t...@kernel.org>
Cc: Michael S. Tsirkin <m...@redhat.com>
Cc: Sridhar Samudrala <samudrala.srid...@gmail.com>
Cc: Li Zefan <l...@cn.fujitsu.com>
---
 drivers/vhost/vhost.c |   34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

Index: work/drivers/vhost/vhost.c
===================================================================
--- work.orig/drivers/vhost/vhost.c
+++ work/drivers/vhost/vhost.c
@@ -23,6 +23,7 @@
 #include <linux/highmem.h>
 #include <linux/slab.h>
 #include <linux/kthread.h>
+#include <linux/cgroup.h>

 #include <linux/net.h>
 #include <linux/if_packet.h>
@@ -187,11 +188,29 @@ long vhost_dev_init(struct vhost_dev *de
                    struct vhost_virtqueue *vqs, int nvqs)
 {
        struct task_struct *worker;
-       int i;
+       cpumask_var_t mask;
+       int i, ret = -ENOMEM;
+
+       if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+               goto out_free_mask;

        worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
-       if (IS_ERR(worker))
-               return PTR_ERR(worker);
+       if (IS_ERR(worker)) {
+               ret = PTR_ERR(worker);
+               goto out_free_mask;
+       }
+
+       ret = sched_getaffinity(current->pid, mask);
+       if (ret)
+               goto out_stop_worker;
+
+       ret = sched_setaffinity(worker->pid, mask);
+       if (ret)
+               goto out_stop_worker;
+
+       ret = cgroup_attach_task_current_cg(worker);
+       if (ret)
+               goto out_stop_worker;

        dev->vqs = vqs;
        dev->nvqs = nvqs;
@@ -214,7 +233,14 @@ long vhost_dev_init(struct vhost_dev *de
        }

        wake_up_process(worker);        /* avoid contributing to loadavg */
-       return 0;
+       ret = 0;
+       goto out_free_mask;
+
+out_stop_worker:
+       kthread_stop(worker);
+out_free_mask:
+       free_cpumask_var(mask);
+       return ret;
 }

 /* Caller should have device mutex */
--
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