man2/splice.2: document SPLICE_F_NOWAIT

Message ID 20230926070402.2452760-1-max.kellermann@ionos.com
State Not applicable
Headers
Series man2/splice.2: document SPLICE_F_NOWAIT |

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Commit Message

Max Kellermann Sept. 26, 2023, 7:04 a.m. UTC
  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(-)
  

Comments

Alejandro Colomar Sept. 26, 2023, 12:01 p.m. UTC | #1
Hi Max,

On Tue, Sep 26, 2023 at 09:04:02AM +0200, Max Kellermann wrote:
> 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>

Please find some formatting issues below.

Cheers,
Alex

> ---
>  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.

.BR EAGAIN .

> +This is analogous to the
> +.B RWF_NOWAIT
> +flag of
> +.BR preadv2()

.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
>
  

Patch

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 (),