[PATCH] splice: add direct fd <-> fd splicing support

It's more efficient for sendfile() emulation. Basically we cache an
internal private pipe and just use that as the intermediate area for
pages. Direct splicing is not available from sys_splice(), it is only
meant to be used for sendfile() emulation.

Additional patch from Ingo Molnar to avoid the PIPE_BUFFERS loop at
exit for the normal fast path.

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 6c2eeb8f6390..1a9787ac6173 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -34,6 +34,7 @@
 #include <linux/mutex.h>
 #include <linux/futex.h>
 #include <linux/compat.h>
+#include <linux/pipe_fs_i.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -941,6 +942,9 @@ fastcall NORET_TYPE void do_exit(long code)
         if (tsk->io_context)
                 exit_io_context();
 
+        if (tsk->splice_pipe)
+                __free_pipe_info(tsk->splice_pipe);
+
         /* PF_DEAD causes final put_task_struct after we schedule. */
         preempt_disable();
         BUG_ON(tsk->flags & PF_DEAD);