vfs: Apply lockdep-based checking to rcu_dereference() uses
Add lockdep-ified RCU primitives to alloc_fd(), files_fdtable()
and fcheck_files().
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
LKML-Reference: <1266887105-1528-8-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index a2ec74b..144412f 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -57,7 +57,11 @@
struct file * fd_array[NR_OPEN_DEFAULT];
};
-#define files_fdtable(files) (rcu_dereference((files)->fdt))
+#define files_fdtable(files) \
+ (rcu_dereference_check((files)->fdt, \
+ rcu_read_lock_held() || \
+ lockdep_is_held(&(files)->file_lock) || \
+ atomic_read(&files->count) == 1))
struct file_operations;
struct vfsmount;
@@ -78,7 +82,7 @@
struct fdtable *fdt = files_fdtable(files);
if (fd < fdt->max_fds)
- file = rcu_dereference(fdt->fd[fd]);
+ file = rcu_dereference_check(fdt->fd[fd], rcu_read_lock_held() || lockdep_is_held(&files->file_lock) || atomic_read(&files->count) == 1);
return file;
}