Re: [patch] bdi: add a user-tunable cpu_list for the bdi flusherthreads

From: Zach Brown
Date: Fri Nov 30 2012 - 17:15:33 EST


> + ret = cpulist_parse(buf, newmask);
> + if (!ret) {
> + spin_lock(&bdi->wb_lock);
> + task = wb->task;
> + get_task_struct(task);
> + spin_unlock(&bdi->wb_lock);
> + if (task)
> + ret = set_cpus_allowed_ptr(task, newmask);
> + put_task_struct(task);

If that test for a non-null task is needed then surely the get and put
need to be similarly protected :).

> + bdi->flusher_cpumask = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
> + if (!bdi->flusher_cpumask)
> + return -ENOMEM;

The bare GFP_KERNEL raises an eyebrow. Some bdi_init() callers like
blk_alloc_queue_node() look like they'll want to pass in a gfp_t for the
allocation.

And shouldn't this be freed in the error path of bdi_init()?

- z
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