Commit-ID: 9080561f06a244fdc3c644c2524d87e819c45232
Gitweb: http://git.kernel.org/tip/9080561f06a244fdc3c644c2524d87e819c45232
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Mon, 4 Jan 2010 18:04:09 -0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 13 Jan 2010 09:42:36 +0100
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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: laijs@xxxxxxxxxxxxxx
Cc: dipankar@xxxxxxxxxx
Cc: mathieu.desnoyers@xxxxxxxxxx
Cc: josh@xxxxxxxxxxxxxxxx
Cc: dvhltc@xxxxxxxxxx
Cc: niv@xxxxxxxxxx
Cc: peterz@xxxxxxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: Valdis.Kletnieks@xxxxxx
Cc: dhowells@xxxxxxxxxx
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
LKML-Reference: <12626570514009-git-send-email->
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
fs/file.c | 2 +-
include/linux/fdtable.h | 7 +++++--
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/file.c b/fs/file.c
index 87e1290..38039af 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -478,7 +478,7 @@ repeat:
error = fd;
#if 1
/* Sanity check */
- if (rcu_dereference(fdt->fd[fd]) != NULL) {
+ if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
rcu_assign_pointer(fdt->fd[fd], NULL);
}
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index a2ec74b..e498a0c 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -57,7 +57,10 @@ struct files_struct {
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)))
struct file_operations;
struct vfsmount;
@@ -78,7 +81,7 @@ static inline struct file * fcheck_files(struct files_struct *files, unsigned in
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));
return file;
}
--
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