pipe: don't use ->i_mutex

now it can be done - put mutex into pipe_inode_info, use it instead
of ->i_mutex

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 7 insertions, 6 deletions

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 1c93e771e950..8a7509f9e6f5 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2465,8 +2465,7 @@ static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
                         out->f_path.dentry->d_name.len,
                         out->f_path.dentry->d_name.name, len);
 
-        if (pipe->inode)
-                mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_PARENT);
+        pipe_lock(pipe);
 
         splice_from_pipe_begin(&sd);
         do {
@@ -2486,8 +2485,7 @@ static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
         } while (ret > 0);
         splice_from_pipe_end(pipe, &sd);
 
-        if (pipe->inode)
-                mutex_unlock(&pipe->inode->i_mutex);
+        pipe_unlock(pipe);
 
         if (sd.num_spliced)
                 ret = sd.num_spliced;
diff --git a/fs/pipe.c b/fs/pipe.c
index abaa9234d27b..d4b97e4e37c5 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -56,7 +56,7 @@ unsigned int pipe_min_size = PAGE_SIZE;
 static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
 {
         if (pipe->inode)
-                mutex_lock_nested(&pipe->inode->i_mutex, subclass);
+                mutex_lock_nested(&pipe->mutex, subclass);
 }
 
 void pipe_lock(struct pipe_inode_info *pipe)
@@ -71,7 +71,7 @@ EXPORT_SYMBOL(pipe_lock);
 void pipe_unlock(struct pipe_inode_info *pipe)
 {
         if (pipe->inode)
-                mutex_unlock(&pipe->inode->i_mutex);
+                mutex_unlock(&pipe->mutex);
 }
 EXPORT_SYMBOL(pipe_unlock);
 
@@ -777,6 +777,7 @@ struct pipe_inode_info * alloc_pipe_info(struct inode *inode)
                         pipe->r_counter = pipe->w_counter = 1;
                         pipe->inode = inode;
                         pipe->buffers = PIPE_DEF_BUFFERS;
+                        mutex_init(&pipe->mutex);
                         return pipe;
                 }
                 kfree(pipe);
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 59778e1c9c08..d803a85a64b6 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -27,6 +27,7 @@ struct pipe_buffer {
 
 /**
  *      struct pipe_inode_info - a linux kernel pipe
+ *      @mutex: mutex protecting the whole thing
  *      @wait: reader/writer wait point in case of empty/full pipe
  *      @nrbufs: the number of non-empty pipe buffers in this pipe
  *      @buffers: total number of buffers (should be a power of 2)
@@ -44,6 +45,7 @@ struct pipe_buffer {
  *      @bufs: the circular array of pipe buffers
  **/
 struct pipe_inode_info {
+        struct mutex mutex;
         wait_queue_head_t wait;
         unsigned int nrbufs, curbuf, buffers;
         unsigned int readers;