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authorRobert Richter <robert.richter@amd.com>2010-10-04 21:09:36 +0200
committerRobert Richter <robert.richter@amd.com>2010-10-12 17:25:06 +0200
commit7df01d96b295e400167e78061b81d4c91630b12d (patch)
tree52782cc1d78c24030d627f719cdaa29846c42efb /drivers/oprofile
parent0361e02342f60b64a7075755d5851ed4e6f98c7d (diff)
oprofile: disable write access to oprofilefs while profiler is running
Oprofile counters are setup when profiling is disabled. Thus, writing to oprofilefs has no immediate effect. Changes are updated only after oprofile is reenabled. To keep userland and kernel states synchronized, we now allow configuration of oprofile only if profiling is disabled. In this case it checks if the profiler is running and then disables write access to oprofilefs by returning -EBUSY. The change should be backward compatible with current oprofile userland daemon. Acked-by: Maynard Johnson <maynardj@us.ibm.com> Cc: William Cohen <wcohen@redhat.com> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'drivers/oprofile')
-rw-r--r--drivers/oprofile/oprof.c21
-rw-r--r--drivers/oprofile/oprof.h2
-rw-r--r--drivers/oprofile/oprofile_files.c7
-rw-r--r--drivers/oprofile/oprofilefs.c8
4 files changed, 18 insertions, 20 deletions
diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
index b4a685719db..f9bda64fcd1 100644
--- a/drivers/oprofile/oprof.c
+++ b/drivers/oprofile/oprof.c
@@ -225,26 +225,17 @@ post_sync:
mutex_unlock(&start_mutex);
}
-int oprofile_set_backtrace(unsigned long val)
+int oprofile_set_ulong(unsigned long *addr, unsigned long val)
{
- int err = 0;
+ int err = -EBUSY;
mutex_lock(&start_mutex);
-
- if (oprofile_started) {
- err = -EBUSY;
- goto out;
+ if (!oprofile_started) {
+ *addr = val;
+ err = 0;
}
-
- if (!oprofile_ops.backtrace) {
- err = -EINVAL;
- goto out;
- }
-
- oprofile_backtrace_depth = val;
-
-out:
mutex_unlock(&start_mutex);
+
return err;
}
diff --git a/drivers/oprofile/oprof.h b/drivers/oprofile/oprof.h
index 47e12cb4ee8..177b73de5e5 100644
--- a/drivers/oprofile/oprof.h
+++ b/drivers/oprofile/oprof.h
@@ -37,7 +37,7 @@ void oprofile_create_files(struct super_block *sb, struct dentry *root);
int oprofile_timer_init(struct oprofile_operations *ops);
void oprofile_timer_exit(void);
-int oprofile_set_backtrace(unsigned long depth);
+int oprofile_set_ulong(unsigned long *addr, unsigned long val);
int oprofile_set_timeout(unsigned long time);
#endif /* OPROF_H */
diff --git a/drivers/oprofile/oprofile_files.c b/drivers/oprofile/oprofile_files.c
index bbd7516e086..ccf099e684a 100644
--- a/drivers/oprofile/oprofile_files.c
+++ b/drivers/oprofile/oprofile_files.c
@@ -79,14 +79,17 @@ static ssize_t depth_write(struct file *file, char const __user *buf, size_t cou
if (*offset)
return -EINVAL;
+ if (!oprofile_ops.backtrace)
+ return -EINVAL;
+
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
return retval;
- retval = oprofile_set_backtrace(val);
-
+ retval = oprofile_set_ulong(&oprofile_backtrace_depth, val);
if (retval)
return retval;
+
return count;
}
diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c
index 789a1a857dd..1944621930d 100644
--- a/drivers/oprofile/oprofilefs.c
+++ b/drivers/oprofile/oprofilefs.c
@@ -91,16 +91,20 @@ static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count
static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
- unsigned long *value = file->private_data;
+ unsigned long value;
int retval;
if (*offset)
return -EINVAL;
- retval = oprofilefs_ulong_from_user(value, buf, count);
+ retval = oprofilefs_ulong_from_user(&value, buf, count);
+ if (retval)
+ return retval;
+ retval = oprofile_set_ulong(file->private_data, value);
if (retval)
return retval;
+
return count;
}