Patch for SPLICE_F_NOWAIT submitted to LKML: https://lore.kernel.org/lkml/20230926063609.2451260-1-max.kellermann@xxxxxxxxx/ In the HISTORY section, I declared Linux 6.7 as the first version to have this feature, but this is only speculation, because SPLICE_F_NOWAIT is still under discussion and has not yet been merged. Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx> --- man2/splice.2 | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/man2/splice.2 b/man2/splice.2 index e9a18e668..a07c001ac 100644 --- a/man2/splice.2 +++ b/man2/splice.2 @@ -89,13 +89,26 @@ call); in the future, a correct implementation may be restored. .TP .B SPLICE_F_NONBLOCK -Do not block on I/O. +Do not block on I/O on pipes. This makes the splice pipe operations nonblocking, but .BR splice () may nevertheless block because the file descriptors that are spliced to/from may block (unless they have the .B O_NONBLOCK -flag set). +flag set or +.B SPLICE_F_NOWAIT +is specified). +.TP +.B SPLICE_F_NOWAIT +If no data is immediately available on +.I fd_in +and it is not a pipe, do not wait (e.g. for backing storage or locks), +but return immediately with +.B EAGAIN. +This is analogous to the +.B RWF_NOWAIT +flag of +.BR preadv2 (). .TP .B SPLICE_F_MORE More data will be coming in a subsequent splice. @@ -138,6 +151,8 @@ is set to indicate the error. .TP .B EAGAIN .B SPLICE_F_NONBLOCK +or +.B SPLICE_F_NOWAIT was specified in .I flags or one of the file descriptors had been marked as nonblocking @@ -192,6 +207,9 @@ was required to be a pipe. Since Linux 2.6.31, .\" commit 7c77f0b3f9208c339a4b40737bb2cb0f0319bb8d both arguments may refer to pipes. +.PP +.B SPLICE_F_NOWAIT +was added in Linux 6.7. .SH NOTES The three system calls .BR splice (), -- 2.39.2
