introduce variants of pipe_lock/pipe_unlock for real pipes/FIFOs

fs/pipe.c file_operations methods *know* that pipe is not an internal one;
no need to check pipe->inode for those callers.

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

1 files changed, 25 insertions, 15 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index 161b2099a7af..e2fc5ccb0d49 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -75,6 +75,16 @@ void pipe_unlock(struct pipe_inode_info *pipe)
 }
 EXPORT_SYMBOL(pipe_unlock);
 
+static inline void __pipe_lock(struct pipe_inode_info *pipe)
+{
+        mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT);
+}
+
+static inline void __pipe_unlock(struct pipe_inode_info *pipe)
+{
+        mutex_unlock(&pipe->mutex);
+}
+
 void pipe_double_lock(struct pipe_inode_info *pipe1,
                       struct pipe_inode_info *pipe2)
 {
@@ -376,7 +386,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
 
         do_wakeup = 0;
         ret = 0;
-        pipe_lock(pipe);
+        __pipe_lock(pipe);
         for (;;) {
                 int bufs = pipe->nrbufs;
                 if (bufs) {
@@ -464,7 +474,7 @@ redo:
                 }
                 pipe_wait(pipe);
         }
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
 
         /* Signal writers asynchronously that there is more room. */
         if (do_wakeup) {
@@ -500,7 +510,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
 
         do_wakeup = 0;
         ret = 0;
-        pipe_lock(pipe);
+        __pipe_lock(pipe);
 
         if (!pipe->readers) {
                 send_sig(SIGPIPE, current, 0);
@@ -647,7 +657,7 @@ redo2:
                 pipe->waiting_writers--;
         }
 out:
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
         if (do_wakeup) {
                 wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
@@ -667,7 +677,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
         switch (cmd) {
                 case FIONREAD:
-                        pipe_lock(pipe);
+                        __pipe_lock(pipe);
                         count = 0;
                         buf = pipe->curbuf;
                         nrbufs = pipe->nrbufs;
@@ -675,7 +685,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                                 count += pipe->bufs[buf].len;
                                 buf = (buf+1) & (pipe->buffers - 1);
                         }
-                        pipe_unlock(pipe);
+                        __pipe_unlock(pipe);
 
                         return put_user(count, (int __user *)arg);
                 default:
@@ -721,7 +731,7 @@ pipe_release(struct inode *inode, struct file *file)
         struct pipe_inode_info *pipe = inode->i_pipe;
         int kill = 0;
 
-        pipe_lock(pipe);
+        __pipe_lock(pipe);
         if (file->f_mode & FMODE_READ)
                 pipe->readers--;
         if (file->f_mode & FMODE_WRITE)
@@ -738,7 +748,7 @@ pipe_release(struct inode *inode, struct file *file)
                 kill = 1;
         }
         spin_unlock(&inode->i_lock);
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
 
         if (kill)
                 __free_pipe_info(pipe);
@@ -752,7 +762,7 @@ pipe_fasync(int fd, struct file *filp, int on)
         struct pipe_inode_info *pipe = filp->private_data;
         int retval = 0;
 
-        pipe_lock(pipe);
+        __pipe_lock(pipe);
         if (filp->f_mode & FMODE_READ)
                 retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
         if ((filp->f_mode & FMODE_WRITE) && retval >= 0) {
@@ -761,7 +771,7 @@ pipe_fasync(int fd, struct file *filp, int on)
                         /* this can happen only if on == T */
                         fasync_helper(-1, filp, 0, &pipe->fasync_readers);
         }
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
         return retval;
 }
 
@@ -1040,7 +1050,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
         filp->private_data = pipe;
         /* OK, we have a pipe and it's pinned down */
 
-        pipe_lock(pipe);
+        __pipe_lock(pipe);
 
         /* We can only do regular read/write on fifos */
         filp->f_mode &= (FMODE_READ | FMODE_WRITE);
@@ -1110,7 +1120,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
         }
 
         /* Ok! */
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
         return 0;
 
 err_rd:
@@ -1132,7 +1142,7 @@ err:
                 kill = 1;
         }
         spin_unlock(&inode->i_lock);
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
         if (kill)
                 __free_pipe_info(pipe);
         return ret;
@@ -1248,7 +1258,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
         if (!pipe)
                 return -EBADF;
 
-        pipe_lock(pipe);
+        __pipe_lock(pipe);
 
         switch (cmd) {
         case F_SETPIPE_SZ: {
@@ -1277,7 +1287,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
         }
 
 out:
-        pipe_unlock(pipe);
+        __pipe_unlock(pipe);
         return ret;
 }