[PATCH] splice: add support for sys_tee()

Basically an in-kernel implementation of tee, which uses splice and the
pipe buffers as an intelligent way to pass data around by reference.

Where the user space tee consumes the input and produces a stdout and
file output, this syscall merely duplicates the data inside a pipe to
another pipe. No data is copied, the output just grabs a reference to the
input pipe data.

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

3 files changed, 3 insertions, 0 deletions

diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index 4f58b9c0efe3..f48bef15b4f0 100644
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -314,3 +314,4 @@ ENTRY(sys_call_table)
         .long sys_get_robust_list
         .long sys_splice
         .long sys_sync_file_range
+        .long sys_tee                   /* 315 */
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 6e16f6b35bd3..e30798811216 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1609,5 +1609,6 @@ sys_call_table:
         data8 sys_set_robust_list
         data8 sys_get_robust_list
         data8 sys_sync_file_range               // 1300
+        data8 sys_tee
 
         .org sys_call_table + 8*NR_syscalls     // guard against failures to increase NR_syscalls
diff --git a/arch/powerpc/kernel/systbl.S b/arch/powerpc/kernel/systbl.S
index 1424eab450ee..a14c96403840 100644
--- a/arch/powerpc/kernel/systbl.S
+++ b/arch/powerpc/kernel/systbl.S
@@ -323,3 +323,4 @@ COMPAT_SYS(pselect6)
 COMPAT_SYS(ppoll)
 SYSCALL(unshare)
 SYSCALL(splice)
+SYSCALL(tee)