fs/pipe: move check to pipe_has_watch_queue()

This declutters the code by reducing the number of #ifdefs and makes
the watch_queue checks simpler.  This has no runtime effect; the
machine code is identical.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Message-Id: <20230921075755.1378787-2-max.kellermann@ionos.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/pipe.c b/fs/pipe.c
index 6c1a9b1db9076c8c1402b7368a25ca7d9a894c70..6ecaccb487388d2925884df9e248cc6989262d81 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -437,12 +437,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
                goto out;
        }
 
-#ifdef CONFIG_WATCH_QUEUE
-       if (pipe->watch_queue) {
+       if (pipe_has_watch_queue(pipe)) {
                ret = -EXDEV;
                goto out;
        }
-#endif
 
        /*
         * If it wasn't empty we try to merge new data into
@@ -1325,10 +1323,8 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned int arg)
        unsigned int nr_slots, size;
        long ret = 0;
 
-#ifdef CONFIG_WATCH_QUEUE
-       if (pipe->watch_queue)
+       if (pipe_has_watch_queue(pipe))
                return -EBUSY;
-#endif
 
        size = round_pipe_size(arg);
        nr_slots = size >> PAGE_SHIFT;
@@ -1380,10 +1376,8 @@ struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice)
 
        if (file->f_op != &pipefifo_fops || !pipe)
                return NULL;
-#ifdef CONFIG_WATCH_QUEUE
-       if (for_splice && pipe->watch_queue)
+       if (for_splice && pipe_has_watch_queue(pipe))
                return NULL;
-#endif
        return pipe;
 }
 

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 598a411d7da2af66596b895f182a895c1d0e56ed..8ff23bf5a81972f9280d09dbc277f4e33dd38683 100644 (file)
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -124,6 +124,22 @@ struct pipe_buf_operations {
        bool (*get)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
+/**
+ * pipe_has_watch_queue - Check whether the pipe is a watch_queue,
+ * i.e. it was created with O_NOTIFICATION_PIPE
+ * @pipe: The pipe to check
+ *
+ * Return: true if pipe is a watch queue, false otherwise.
+ */
+static inline bool pipe_has_watch_queue(const struct pipe_inode_info *pipe)
+{
+#ifdef CONFIG_WATCH_QUEUE
+       return pipe->watch_queue != NULL;
+#else
+       return false;
+#endif
+}
+
 /**
  * pipe_empty - Return true if the pipe is empty
  * @head: The pipe ring head pointer