oprofile: add op_cpu_buffer_get_data()
This function provides access to attached data of a sample. It returns
the size of data including the current value. Also,
op_cpu_buffer_get_size() is available to check if there is data
attached.
Signed-off-by: Robert Richter <robert.richter@amd.com>
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index d969bb1..f9031d3 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -524,6 +524,7 @@
{
struct mm_struct *mm = NULL;
struct mm_struct *oldmm;
+ unsigned long val;
struct task_struct *new;
unsigned long cookie = 0;
int in_kernel = 1;
@@ -559,10 +560,11 @@
state = sb_sample_start;
add_kernel_ctx_switch(flags & IS_KERNEL);
}
- if (flags & USER_CTX_SWITCH) {
+ if (flags & USER_CTX_SWITCH
+ && op_cpu_buffer_get_data(&entry, &val)) {
/* userspace context switch */
+ new = (struct task_struct *)val;
oldmm = mm;
- new = (struct task_struct *)sample->data[0];
release_mm(oldmm);
mm = take_tasks_mm(new);
if (mm != oldmm)
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index e178dd2..f343760 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -90,6 +90,26 @@
return entry->size;
}
+/* returns the size of data in the entry */
+static inline
+int op_cpu_buffer_get_size(struct op_entry *entry)
+{
+ return entry->size;
+}
+
+/* returns 0 if empty or the size of data including the current value */
+static inline
+int op_cpu_buffer_get_data(struct op_entry *entry, unsigned long *val)
+{
+ int size = entry->size;
+ if (!size)
+ return 0;
+ *val = *entry->data;
+ entry->size--;
+ entry->data++;
+ return size;
+}
+
/* extra data flags */
#define KERNEL_CTX_SWITCH (1UL << 0)
#define IS_KERNEL (1UL << 1)