tracing: use pointer error returns for __tracing_open
Impact: fix compile warning and clean up
When I first wrote __tracing_open, instead of passing the error
code via the ERR_PTR macros, I lazily used a separate parameter
to hold the return for errors.
When Frederic Weisbecker updated that function, he used the Linux
kernel ERR_PTR for the returns. This caused the parameter return
to possibly not be initialized on error. gcc correctly pointed this
out with a warning.
This patch converts the entire function to use the Linux kernel
ERR_PTR macro methods.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6c89ec6..304e02c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1684,23 +1684,20 @@
};
static struct trace_iterator *
-__tracing_open(struct inode *inode, struct file *file, int *ret)
+__tracing_open(struct inode *inode, struct file *file)
{
long cpu_file = (long) inode->i_private;
+ void *fail_ret = ERR_PTR(-ENOMEM);
struct trace_iterator *iter;
struct seq_file *m;
- int cpu;
+ int cpu, ret;
- if (tracing_disabled) {
- *ret = -ENODEV;
- return NULL;
- }
+ if (tracing_disabled)
+ return ERR_PTR(-ENODEV);
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
- if (!iter) {
- *ret = -ENOMEM;
- goto out;
- }
+ if (!iter)
+ return ERR_PTR(-ENOMEM);
/*
* We make a copy of the current tracer to avoid concurrent
@@ -1708,10 +1705,9 @@
*/
mutex_lock(&trace_types_lock);
iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
- if (!iter->trace) {
- *ret = -ENOMEM;
+ if (!iter->trace)
goto fail;
- }
+
if (current_trace)
*iter->trace = *current_trace;
@@ -1750,9 +1746,11 @@
}
/* TODO stop tracer */
- *ret = seq_open(file, &tracer_seq_ops);
- if (*ret)
+ ret = seq_open(file, &tracer_seq_ops);
+ if (ret < 0) {
+ fail_ret = ERR_PTR(ret);
goto fail_buffer;
+ }
m = file->private_data;
m->private = iter;
@@ -1762,7 +1760,6 @@
mutex_unlock(&trace_types_lock);
- out:
return iter;
fail_buffer:
@@ -1775,7 +1772,7 @@
kfree(iter->trace);
kfree(iter);
- return ERR_PTR(-ENOMEM);
+ return fail_ret;
}
int tracing_open_generic(struct inode *inode, struct file *filp)
@@ -1815,9 +1812,12 @@
static int tracing_open(struct inode *inode, struct file *file)
{
- int ret;
+ struct trace_iterator *iter;
+ int ret = 0;
- __tracing_open(inode, file, &ret);
+ iter = __tracing_open(inode, file);
+ if (IS_ERR(iter))
+ ret = PTR_ERR(iter);
return ret;
}
@@ -1825,11 +1825,13 @@
static int tracing_lt_open(struct inode *inode, struct file *file)
{
struct trace_iterator *iter;
- int ret;
+ int ret = 0;
- iter = __tracing_open(inode, file, &ret);
+ iter = __tracing_open(inode, file);
- if (!ret)
+ if (IS_ERR(iter))
+ ret = PTR_ERR(iter);
+ else
iter->iter_flags |= TRACE_FILE_LAT_FMT;
return ret;
