[RFC PATCH v2 13/15] tracing: of: Add cpumask property support

[Masami Hiramatsu]

Add cpumask property for tracing. Note that this property accepts
a string cpumask, not a digit number.

Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
---
 kernel/trace/trace.c    |   41 ++++++++++++++++++++++++++++-------------
 kernel/trace/trace_of.c |   14 ++++++++++++++
 2 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6f50c58a3ad4..251d9de14b12 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4437,20 +4437,12 @@ tracing_cpumask_read(struct file *filp, char __user 
*ubuf,
        return count;
 }
 
-static ssize_t
-tracing_cpumask_write(struct file *filp, const char __user *ubuf,
-                     size_t count, loff_t *ppos)
+int tracing_set_cpumask(struct trace_array *tr, cpumask_var_t 
tracing_cpumask_new)
 {
-       struct trace_array *tr = file_inode(filp)->i_private;
-       cpumask_var_t tracing_cpumask_new;
-       int err, cpu;
-
-       if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
-               return -ENOMEM;
+       int cpu;
 
-       err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
-       if (err)
-               goto err_unlock;
+       if (!tr)
+               return -EINVAL;
 
        local_irq_disable();
        arch_spin_lock(&tr->max_lock);
@@ -4474,11 +4466,34 @@ tracing_cpumask_write(struct file *filp, const char 
__user *ubuf,
        local_irq_enable();
 
        cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
+
+       return 0;
+}
+
+static ssize_t
+tracing_cpumask_write(struct file *filp, const char __user *ubuf,
+                     size_t count, loff_t *ppos)
+{
+       struct trace_array *tr = file_inode(filp)->i_private;
+       cpumask_var_t tracing_cpumask_new;
+       int err;
+
+       if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+               return -ENOMEM;
+
+       err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
+       if (err)
+               goto err_free;
+
+       err = tracing_set_cpumask(tr, tracing_cpumask_new);
+       if (err)
+               goto err_free;
+
        free_cpumask_var(tracing_cpumask_new);
 
        return count;
 
-err_unlock:
+err_free:
        free_cpumask_var(tracing_cpumask_new);
 
        return err;
diff --git a/kernel/trace/trace_of.c b/kernel/trace/trace_of.c
index 7fe81c25dc59..14d6c9a8fd81 100644
--- a/kernel/trace/trace_of.c
+++ b/kernel/trace/trace_of.c
@@ -22,6 +22,8 @@ extern void __init trace_init_tracepoint_printk(void);
 extern ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
                                          unsigned long size, int cpu_id);
 extern struct trace_array *trace_array_create(const char *name);
+extern int tracing_set_cpumask(struct trace_array *tr,
+                              cpumask_var_t tracing_cpumask_new);
 
 static void __init
 trace_of_set_instance_options(struct trace_array *tr, struct device_node *node)
@@ -59,6 +61,18 @@ trace_of_set_instance_options(struct trace_array *tr, struct 
device_node *node)
                        pr_err("Failed to resize trace buffer to %d KB\n",
                                v >> 10);
        }
+
+       err = of_property_read_string(node, "cpumask", &p);
+       if (!err) {
+               cpumask_var_t new_mask;
+
+               if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+                       if (cpumask_parse(p, new_mask) < 0 ||
+                           tracing_set_cpumask(tr, new_mask) < 0)
+                               pr_err("Failed to set new CPU mask %s\n", p);
+                       free_cpumask_var(new_mask);
+               }
+       }
 }
 
 static void __init