replace ->follow_link() with new method that could stay in RCU mode
new method: ->get_link(); replacement of ->follow_link(). The differences
are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.
It's a flagday change - the old method is gone, all in-tree instances
converted. Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode. That'll change
in the next commits.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
index 947b0f4..50eef6f 100644
--- a/fs/proc/thread_self.c
+++ b/fs/proc/thread_self.c
@@ -19,13 +19,16 @@
return readlink_copy(buffer, buflen, tmp);
}
-static const char *proc_thread_self_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_thread_self_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+ struct pid_namespace *ns = inode->i_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
pid_t pid = task_pid_nr_ns(current, ns);
char *name;
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
if (!pid)
return ERR_PTR(-ENOENT);
name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
@@ -37,7 +40,7 @@
static const struct inode_operations proc_thread_self_inode_operations = {
.readlink = proc_thread_self_readlink,
- .follow_link = proc_thread_self_follow_link,
+ .get_link = proc_thread_self_get_link,
.put_link = kfree_put_link,
};