get rid of pipe->inode

it's used only as a flag to distinguish normal pipes/FIFOs from the
internal per-task one used by file-to-file splice.  And pipe->files
would work just as well for that purpose...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 11dfa0c..9bfd1a3 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1319,7 +1319,7 @@
 		page_nr++;
 		ret += buf->len;
 
-		if (pipe->inode)
+		if (pipe->files)
 			do_wakeup = 1;
 	}
 
diff --git a/fs/pipe.c b/fs/pipe.c
index e2fc5cc..39bdec0 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -55,7 +55,7 @@
 
 static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
 {
-	if (pipe->inode)
+	if (pipe->files)
 		mutex_lock_nested(&pipe->mutex, subclass);
 }
 
@@ -70,7 +70,7 @@
 
 void pipe_unlock(struct pipe_inode_info *pipe)
 {
-	if (pipe->inode)
+	if (pipe->files)
 		mutex_unlock(&pipe->mutex);
 }
 EXPORT_SYMBOL(pipe_unlock);
@@ -785,7 +785,6 @@
 		if (pipe->bufs) {
 			init_waitqueue_head(&pipe->wait);
 			pipe->r_counter = pipe->w_counter = 1;
-			pipe->inode = inode;
 			pipe->buffers = PIPE_DEF_BUFFERS;
 			mutex_init(&pipe->mutex);
 			return pipe;
diff --git a/fs/splice.c b/fs/splice.c
index 7efc2f5..9f2a4447 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -218,7 +218,7 @@
 			page_nr++;
 			ret += buf->len;
 
-			if (pipe->inode)
+			if (pipe->files)
 				do_wakeup = 1;
 
 			if (!--spd->nr_pages)
@@ -828,7 +828,7 @@
 			ops->release(pipe, buf);
 			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
 			pipe->nrbufs--;
-			if (pipe->inode)
+			if (pipe->files)
 				sd->need_wakeup = true;
 		}