On Mon, Mar 19, 2018 at 12:08:09PM +0200, Leon Romanovsky wrote:
> > 794 static ssize_t show_hw_stats(struct kobject *kobj, struct attribute *attr,
> > 795 char *buf)
> > 796 {
> > 797 struct ib_device *dev;
> > 798 struct ib_port *port;
> > 799 struct hw_stats_attribute *hsa;
> > 800 struct rdma_hw_stats *stats;
> > 801 int ret;
> > 802
> > 803 hsa = container_of(attr, struct hw_stats_attribute, attr);
> > 804 if (!hsa->port_num) {
> > 805 dev = container_of((struct device *)kobj,
> > 806 struct ib_device, dev);
> > 807 stats = dev->hw_stats;
> > 808 } else {
> > 809 port = container_of(kobj, struct ib_port, kobj);
> > 810 dev = port->ibdev;
> > 811 stats = port->hw_stats;
>
> Mark pointed to me that "stats" is actually pointer to shared memory.
Yes it is.
So either stats should be made thread local here, or we need the lock.
You can't rely on ordinary writes to shared memory to do anything
sane, only atomic writes have sensible properties.
I can't think of any reason why adding this lock would be bad?
Jason
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