From: Max Kellermann <max.kellermann@ionos.com>
To: alx@kernel.org, linux-man@vger.kernel.org, brauner@kernel.org,
axboe@kernel.dk
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
libc-alpha@sourceware.org,
Max Kellermann <max.kellermann@ionos.com>
Subject: [PATCH] man2/splice.2: document SPLICE_F_NOWAIT
Date: Tue, 26 Sep 2023 09:04:02 +0200 [thread overview]
Message-ID: <20230926070402.2452760-1-max.kellermann@ionos.com> (raw)
Patch for SPLICE_F_NOWAIT submitted to LKML:
https://lore.kernel.org/lkml/20230926063609.2451260-1-max.kellermann@ionos.com/
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@ionos.com>
---
man2/splice.2 | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/man2/splice.2 b/man2/splice.2
index e9a18e668..1e686b858 100644
--- a/man2/splice.2
+++ b/man2/splice.2
@@ -89,13 +89,27 @@ 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 +152,8 @@ 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 +208,9 @@ 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
next reply other threads:[~2023-09-26 7:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-26 7:04 Max Kellermann [this message]
2023-09-26 12:01 ` [PATCH] man2/splice.2: document SPLICE_F_NOWAIT Alejandro Colomar
2023-09-26 13:43 ` [PATCH v2] " Max Kellermann
2023-09-27 11:29 ` Alejandro Colomar
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