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| author | Nicolai Stange <nicstange@gmail.com> | 2017-10-31 00:15:53 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-07 20:25:03 +0100 |
| commit | 154b9d7512ae012aca7b4e90af67a72419ad1941 (patch) | |
| tree | 565b3295b5abdf575d519b336b01f1f8c1713224 /fs/debugfs | |
| parent | c9afbec27089cd6b4e621b639f41c7fc726c3bf1 (diff) | |
| download | lwn-154b9d7512ae012aca7b4e90af67a72419ad1941.tar.gz lwn-154b9d7512ae012aca7b4e90af67a72419ad1941.zip | |
debugfs: call debugfs_real_fops() only after debugfs_file_get()
The current implementation of debugfs_real_fops() relies on a
debugfs_fsdata instance to be installed at ->d_fsdata.
With future patches introducing lazy allocation of these, this requirement
will be guaranteed to be fullfilled only inbetween a
debugfs_file_get()/debugfs_file_put() pair.
The full proxies' fops implemented by debugfs happen to be the only
offenders. Fix them up by moving their debugfs_real_fops() calls past those
to debugfs_file_get().
full_proxy_release() is special as it doesn't invoke debugfs_file_get() at
all. Leave it alone for now.
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/debugfs')
| -rw-r--r-- | fs/debugfs/file.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 53f5c9a2af88..bc3549c95574 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -144,13 +144,13 @@ const struct file_operations debugfs_open_proxy_file_operations = { static ret_type full_proxy_ ## name(proto) \ { \ struct dentry *dentry = F_DENTRY(filp); \ - const struct file_operations *real_fops = \ - debugfs_real_fops(filp); \ + const struct file_operations *real_fops; \ ret_type r; \ \ r = debugfs_file_get(dentry); \ if (unlikely(r)) \ return r; \ + real_fops = debugfs_real_fops(filp); \ r = real_fops->name(args); \ debugfs_file_put(dentry); \ return r; \ @@ -177,13 +177,14 @@ FULL_PROXY_FUNC(unlocked_ioctl, long, filp, static unsigned int full_proxy_poll(struct file *filp, struct poll_table_struct *wait) { - const struct file_operations *real_fops = debugfs_real_fops(filp); struct dentry *dentry = F_DENTRY(filp); unsigned int r = 0; + const struct file_operations *real_fops; if (debugfs_file_get(dentry)) return POLLHUP; + real_fops = debugfs_real_fops(filp); r = real_fops->poll(filp, wait); debugfs_file_put(dentry); return r; |