1 files changed, 77 insertions, 74 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index ba4376341ddd..12b22c2723b7 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -76,18 +76,20 @@ static unsigned long pipe_user_pages_soft = PIPE_DEF_BUFFERS * INR_OPEN_CUR;
  * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09
  */
 
-static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
+#define cmp_int(l, r)		((l > r) - (l < r))
+
+#ifdef CONFIG_PROVE_LOCKING
+static int pipe_lock_cmp_fn(const struct lockdep_map *a,
+			    const struct lockdep_map *b)
 {
-	if (pipe->files)
-		mutex_lock_nested(&pipe->mutex, subclass);
+	return cmp_int((unsigned long) a, (unsigned long) b);
 }
+#endif
 
 void pipe_lock(struct pipe_inode_info *pipe)
 {
-	/*
-	 * pipe_lock() nests non-pipe inode locks (for writing to a file)
-	 */
-	pipe_lock_nested(pipe, I_MUTEX_PARENT);
+	if (pipe->files)
+		mutex_lock(&pipe->mutex);
 }
 EXPORT_SYMBOL(pipe_lock);
 
@@ -98,28 +100,16 @@ 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)
 {
 	BUG_ON(pipe1 == pipe2);
 
-	if (pipe1 < pipe2) {
-		pipe_lock_nested(pipe1, I_MUTEX_PARENT);
-		pipe_lock_nested(pipe2, I_MUTEX_CHILD);
-	} else {
-		pipe_lock_nested(pipe2, I_MUTEX_PARENT);
-		pipe_lock_nested(pipe1, I_MUTEX_CHILD);
-	}
+	if (pipe1 > pipe2)
+		swap(pipe1, pipe2);
+
+	pipe_lock(pipe1);
+	pipe_lock(pipe2);
 }
 
 static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
@@ -227,6 +217,36 @@ static inline bool pipe_readable(const struct pipe_inode_info *pipe)
 	return !pipe_empty(head, tail) || !writers;
 }
 
+static inline unsigned int pipe_update_tail(struct pipe_inode_info *pipe,
+					    struct pipe_buffer *buf,
+					    unsigned int tail)
+{
+	pipe_buf_release(pipe, buf);
+
+	/*
+	 * If the pipe has a watch_queue, we need additional protection
+	 * by the spinlock because notifications get posted with only
+	 * this spinlock, no mutex
+	 */
+	if (pipe_has_watch_queue(pipe)) {
+		spin_lock_irq(&pipe->rd_wait.lock);
+#ifdef CONFIG_WATCH_QUEUE
+		if (buf->flags & PIPE_BUF_FLAG_LOSS)
+			pipe->note_loss = true;
+#endif
+		pipe->tail = ++tail;
+		spin_unlock_irq(&pipe->rd_wait.lock);
+		return tail;
+	}
+
+	/*
+	 * Without a watch_queue, we can simply increment the tail
+	 * without the spinlock - the mutex is enough.
+	 */
+	pipe->tail = ++tail;
+	return tail;
+}
+
 static ssize_t
 pipe_read(struct kiocb *iocb, struct iov_iter *to)
 {
@@ -241,7 +261,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 		return 0;
 
 	ret = 0;
-	__pipe_lock(pipe);
+	mutex_lock(&pipe->mutex);
 
 	/*
 	 * We only wake up writers if the pipe was full when we started
@@ -320,17 +340,8 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 				buf->len = 0;
 			}
 
-			if (!buf->len) {
-				pipe_buf_release(pipe, buf);
-				spin_lock_irq(&pipe->rd_wait.lock);
-#ifdef CONFIG_WATCH_QUEUE
-				if (buf->flags & PIPE_BUF_FLAG_LOSS)
-					pipe->note_loss = true;
-#endif
-				tail++;
-				pipe->tail = tail;
-				spin_unlock_irq(&pipe->rd_wait.lock);
-			}
+			if (!buf->len)
+				tail = pipe_update_tail(pipe, buf, tail);
 			total_len -= chars;
 			if (!total_len)
 				break;	/* common path: read succeeded */
@@ -347,7 +358,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 			ret = -EAGAIN;
 			break;
 		}
-		__pipe_unlock(pipe);
+		mutex_unlock(&pipe->mutex);
 
 		/*
 		 * We only get here if we didn't actually read anything.
@@ -379,13 +390,13 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 		if (wait_event_interruptible_exclusive(pipe->rd_wait, pipe_readable(pipe)) < 0)
 			return -ERESTARTSYS;
 
-		__pipe_lock(pipe);
+		mutex_lock(&pipe->mutex);
 		was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage);
 		wake_next_reader = true;
 	}
 	if (pipe_empty(pipe->head, pipe->tail))
 		wake_next_reader = false;
-	__pipe_unlock(pipe);
+	mutex_unlock(&pipe->mutex);
 
 	if (was_full)
 		wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
@@ -441,7 +452,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 	if (unlikely(total_len == 0))
 		return 0;
 
-	__pipe_lock(pipe);
+	mutex_lock(&pipe->mutex);
 
 	if (!pipe->readers) {
 		send_sig(SIGPIPE, current, 0);
@@ -512,16 +523,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 			 * it, either the reader will consume it or it'll still
 			 * be there for the next write.
 			 */
-			spin_lock_irq(&pipe->rd_wait.lock);
-
-			head = pipe->head;
-			if (pipe_full(head, pipe->tail, pipe->max_usage)) {
-				spin_unlock_irq(&pipe->rd_wait.lock);
-				continue;
-			}
-
 			pipe->head = head + 1;
-			spin_unlock_irq(&pipe->rd_wait.lock);
 
 			/* Insert it into the buffer array */
 			buf = &pipe->bufs[head & mask];
@@ -570,19 +572,19 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 		 * after waiting we need to re-check whether the pipe
 		 * become empty while we dropped the lock.
 		 */
-		__pipe_unlock(pipe);
+		mutex_unlock(&pipe->mutex);
 		if (was_empty)
 			wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
 		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 		wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe));
-		__pipe_lock(pipe);
+		mutex_lock(&pipe->mutex);
 		was_empty = pipe_empty(pipe->head, pipe->tail);
 		wake_next_writer = true;
 	}
 out:
 	if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
 		wake_next_writer = false;
-	__pipe_unlock(pipe);
+	mutex_unlock(&pipe->mutex);
 
 	/*
 	 * If we do do a wakeup event, we do a 'sync' wakeup, because we
@@ -617,7 +619,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 	switch (cmd) {
 	case FIONREAD:
-		__pipe_lock(pipe);
+		mutex_lock(&pipe->mutex);
 		count = 0;
 		head = pipe->head;
 		tail = pipe->tail;
@@ -627,16 +629,16 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			count += pipe->bufs[tail & mask].len;
 			tail++;
 		}
-		__pipe_unlock(pipe);
+		mutex_unlock(&pipe->mutex);
 
 		return put_user(count, (int __user *)arg);
 
 #ifdef CONFIG_WATCH_QUEUE
 	case IOC_WATCH_QUEUE_SET_SIZE: {
 		int ret;
-		__pipe_lock(pipe);
+		mutex_lock(&pipe->mutex);
 		ret = watch_queue_set_size(pipe, arg);
-		__pipe_unlock(pipe);
+		mutex_unlock(&pipe->mutex);
 		return ret;
 	}
 
@@ -684,7 +686,7 @@ pipe_poll(struct file *filp, poll_table *wait)
 	if (filp->f_mode & FMODE_READ) {
 		if (!pipe_empty(head, tail))
 			mask |= EPOLLIN | EPOLLRDNORM;
-		if (!pipe->writers && filp->f_version != pipe->w_counter)
+		if (!pipe->writers && filp->f_pipe != pipe->w_counter)
 			mask |= EPOLLHUP;
 	}
 
@@ -722,7 +724,7 @@ pipe_release(struct inode *inode, struct file *file)
 {
 	struct pipe_inode_info *pipe = file->private_data;
 
-	__pipe_lock(pipe);
+	mutex_lock(&pipe->mutex);
 	if (file->f_mode & FMODE_READ)
 		pipe->readers--;
 	if (file->f_mode & FMODE_WRITE)
@@ -735,7 +737,7 @@ pipe_release(struct inode *inode, struct file *file)
 		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 		kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
 	}
-	__pipe_unlock(pipe);
+	mutex_unlock(&pipe->mutex);
 
 	put_pipe_info(inode, pipe);
 	return 0;
@@ -747,7 +749,7 @@ pipe_fasync(int fd, struct file *filp, int on)
 	struct pipe_inode_info *pipe = filp->private_data;
 	int retval = 0;
 
-	__pipe_lock(pipe);
+	mutex_lock(&pipe->mutex);
 	if (filp->f_mode & FMODE_READ)
 		retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
 	if ((filp->f_mode & FMODE_WRITE) && retval >= 0) {
@@ -756,7 +758,7 @@ 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);
+	mutex_unlock(&pipe->mutex);
 	return retval;
 }
 
@@ -822,6 +824,7 @@ struct pipe_inode_info *alloc_pipe_info(void)
 		pipe->nr_accounted = pipe_bufs;
 		pipe->user = user;
 		mutex_init(&pipe->mutex);
+		lock_set_cmp_fn(&pipe->mutex, pipe_lock_cmp_fn, NULL);
 		return pipe;
 	}
 
@@ -859,7 +862,7 @@ void free_pipe_info(struct pipe_inode_info *pipe)
 	kfree(pipe);
 }
 
-static struct vfsmount *pipe_mnt __read_mostly;
+static struct vfsmount *pipe_mnt __ro_after_init;
 
 /*
  * pipefs_dname() is called from d_path().
@@ -903,7 +906,7 @@ static struct inode * get_pipe_inode(void)
 	inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR;
 	inode->i_uid = current_fsuid();
 	inode->i_gid = current_fsgid();
-	inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
+	simple_inode_init_ts(inode);
 
 	return inode;
 
@@ -942,6 +945,7 @@ int create_pipe_files(struct file **res, int flags)
 	}
 
 	f->private_data = inode->i_pipe;
+	f->f_pipe = 0;
 
 	res[0] = alloc_file_clone(f, O_RDONLY | (flags & O_NONBLOCK),
 				  &pipefifo_fops);
@@ -951,6 +955,7 @@ int create_pipe_files(struct file **res, int flags)
 		return PTR_ERR(res[0]);
 	}
 	res[0]->private_data = inode->i_pipe;
+	res[0]->f_pipe = 0;
 	res[1] = f;
 	stream_open(inode, res[0]);
 	stream_open(inode, res[1]);
@@ -1105,7 +1110,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
 	bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC;
 	int ret;
 
-	filp->f_version = 0;
+	filp->f_pipe = 0;
 
 	spin_lock(&inode->i_lock);
 	if (inode->i_pipe) {
@@ -1132,7 +1137,7 @@ 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);
+	mutex_lock(&pipe->mutex);
 
 	/* We can only do regular read/write on fifos */
 	stream_open(inode, filp);
@@ -1152,7 +1157,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
 			if ((filp->f_flags & O_NONBLOCK)) {
 				/* suppress EPOLLHUP until we have
 				 * seen a writer */
-				filp->f_version = pipe->w_counter;
+				filp->f_pipe = pipe->w_counter;
 			} else {
 				if (wait_for_partner(pipe, &pipe->w_counter))
 					goto err_rd;
@@ -1202,7 +1207,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
 	}
 
 	/* Ok! */
-	__pipe_unlock(pipe);
+	mutex_unlock(&pipe->mutex);
 	return 0;
 
 err_rd:
@@ -1218,7 +1223,7 @@ err_wr:
 	goto err;
 
 err:
-	__pipe_unlock(pipe);
+	mutex_unlock(&pipe->mutex);
 
 	put_pipe_info(inode, pipe);
 	return ret;
@@ -1226,7 +1231,6 @@ err:
 
 const struct file_operations pipefifo_fops = {
 	.open		= fifo_open,
-	.llseek		= no_llseek,
 	.read_iter	= pipe_read,
 	.write_iter	= pipe_write,
 	.poll		= pipe_poll,
@@ -1399,7 +1403,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
 	if (!pipe)
 		return -EBADF;
 
-	__pipe_lock(pipe);
+	mutex_lock(&pipe->mutex);
 
 	switch (cmd) {
 	case F_SETPIPE_SZ:
@@ -1413,7 +1417,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
 		break;
 	}
 
-	__pipe_unlock(pipe);
+	mutex_unlock(&pipe->mutex);
 	return ret;
 }
 
@@ -1424,7 +1428,7 @@ static const struct super_operations pipefs_ops = {
 
 /*
  * pipefs should _never_ be mounted by userland - too much of security hassle,
- * no real gain from having the whole whorehouse mounted. So we don't need
+ * no real gain from having the whole file system mounted. So we don't need
  * any operations on the root directory. However, we need a non-trivial
  * d_name - pipe: will go nicely and kill the special-casing in procfs.
  */
@@ -1466,7 +1470,7 @@ static int do_proc_dopipe_max_size_conv(unsigned long *lvalp,
 	return 0;
 }
 
-static int proc_dopipe_max_size(struct ctl_table *table, int write,
+static int proc_dopipe_max_size(const struct ctl_table *table, int write,
 				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
@@ -1495,7 +1499,6 @@ static struct ctl_table fs_pipe_sysctls[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_doulongvec_minmax,
 	},
-	{ }
 };
 #endif