Currently, the struct file_operations fops_bool associated with files
created through the debugfs_create_bool() helpers are not file
lifetime aware.
Thus, a lifetime managing proxy is created around fops_bool each time such
a file is opened which is an unnecessary waste of resources.
Implement file lifetime management for the fops_bool file_operations.
Namely, make debugfs_read_file_bool() and debugfs_write_file_bool() safe
against file removals by means of debugfs_use_file_start() and
debugfs_use_file_finish().
Make debugfs_create_bool() create its files in non-proxying operation mode
through debugfs_create_mode_unsafe().
Finally, purge debugfs_create_mode() as debugfs_create_bool() had been its
last user.
Signed-off-by: Nicolai Stange <nicsta...@gmail.com>
---
fs/debugfs/file.c | 41 ++++++++++++++++++++---------------------
1 file changed, 20 insertions(+), 21 deletions(-)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 74de110..da24e0b 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -313,22 +313,6 @@ ssize_t debugfs_attr_write(struct file *file, const char
__user *buf,
}
EXPORT_SYMBOL_GPL(debugfs_attr_write);
-static struct dentry *debugfs_create_mode(const char *name, umode_t mode,
- struct dentry *parent, void *value,
- const struct file_operations *fops,
- const struct file_operations *fops_ro,
- const struct file_operations *fops_wo)
-{
- /* if there are no write bits set, make read only */
- if (!(mode & S_IWUGO))
- return debugfs_create_file(name, mode, parent, value, fops_ro);
- /* if there are no read bits set, make write only */
- if (!(mode & S_IRUGO))
- return debugfs_create_file(name, mode, parent, value, fops_wo);
-
- return debugfs_create_file(name, mode, parent, value, fops);
-}
-
static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t
mode,
struct dentry *parent, void *value,
const struct file_operations *fops,
@@ -757,9 +741,17 @@ ssize_t debugfs_read_file_bool(struct file *file, char
__user *user_buf,
size_t count, loff_t *ppos)
{
char buf[3];
- bool *val = file->private_data;
+ bool val;
+ int r, srcu_idx;
+
+ r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
+ if (likely(!r))
+ val = *(bool *)file->private_data;
+ debugfs_use_file_finish(srcu_idx);
+ if (r)
+ return r;
- if (*val)
+ if (val)
buf[0] = 'Y';
else
buf[0] = 'N';
@@ -775,6 +767,7 @@ ssize_t debugfs_write_file_bool(struct file *file, const
char __user *user_buf,
char buf[32];
size_t buf_size;
bool bv;
+ int r, srcu_idx;
bool *val = file->private_data;
buf_size = min(count, (sizeof(buf)-1));
@@ -782,8 +775,14 @@ ssize_t debugfs_write_file_bool(struct file *file, const
char __user *user_buf,
return -EFAULT;
buf[buf_size] = '\0';
- if (strtobool(buf, &bv) == 0)
- *val = bv;
+ if (strtobool(buf, &bv) == 0) {
+ r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
+ if (likely(!r))
+ *val = bv;
+ debugfs_use_file_finish(srcu_idx);
+ if (r)
+ return r;
+ }
return count;
}
@@ -835,7 +834,7 @@ static const struct file_operations fops_bool_wo = {
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
struct dentry *parent, bool *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_bool,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
&fops_bool_ro, &fops_bool_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_bool);
--
2.7.1
