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, 6 insertions, 0 deletions

diff --git a/include/linux/fcntl.h b/include/linux/fcntl.h
index 86037400a6e3..afc00af3229b 100644
--- a/include/linux/fcntl.h
+++ b/include/linux/fcntl.h
@@ -22,6 +22,12 @@
 #define F_NOTIFY        (F_LINUX_SPECIFIC_BASE+2)
 
 /*
+ * Set and get of pipe page size array
+ */
+#define F_SETPIPE_SZ    (F_LINUX_SPECIFIC_BASE + 7)
+#define F_GETPIPE_SZ    (F_LINUX_SPECIFIC_BASE + 8)
+
+/*
  * Types of directory notifications that may be requested.
  */
 #define DN_ACCESS       0x00000001      /* File accessed */