pipe: add support for shrinking and growing pipes

This patch adds F_GETPIPE_SZ and F_SETPIPE_SZ fcntl() actions for
growing and shrinking the size of a pipe and adjusts pipe.c and splice.c
(and relay and network splice) usage to work with these larger (or smaller)
pipes.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 452d02f9075e..bcba960328fa 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -14,6 +14,7 @@
 #include <linux/dnotify.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/pipe_fs_i.h>
 #include <linux/security.h>
 #include <linux/ptrace.h>
 #include <linux/signal.h>
@@ -412,6 +413,10 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
         case F_NOTIFY:
                 err = fcntl_dirnotify(fd, filp, arg);
                 break;
+        case F_SETPIPE_SZ:
+        case F_GETPIPE_SZ:
+                err = pipe_fcntl(filp, cmd, arg);
+                break;
         default:
                 break;
         }