Hello Adam, On 07/13/2018 10:58 PM, adam.manzanares@xxxxxxx wrote:
From: Adam Manzanares <adam.manzanares@xxxxxxx> The newly added IOCB_FLAG_IOPRIO aio_flag introduces new behaviors and return values. The details of this new feature are posted here: https://lkml.org/lkml/2018/5/22/809
Thanks for this patch. I've applied it, but I have a question below about a detail that probably needs fixing.
Signed-off-by: Adam Manzanares <adam.manzanares@xxxxxxx> --- man2/io_submit.2 | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) diff --git a/man2/io_submit.2 b/man2/io_submit.2 index d17e3122a..15e1ecdea 100644 --- a/man2/io_submit.2 +++ b/man2/io_submit.2 @@ -164,14 +164,26 @@ This is the size of the buffer pointed to by This is the file offset at which the I/O operation is to be performed. .TP .I aio_flags -This is the flag to be passed iocb structure. -The only valid value is -.BR IOCB_FLAG_RESFD , -which indicates that the asynchronous I/O control must signal the file +This is the set of flags associated with the iocb structure. +The valid values are: +.RS +.TP +.BR IOCB_FLAG_RESFD +Asynchronous I/O control must signal the file descriptor mentioned in .I aio_resfd upon completion. .TP +.BR IOCB_FLAG_IOPRIO " (since Linux 4.18)" +.\" commit d9a08a9e616beeccdbd0e7262b7225ffdfa49e92 +Interpret the +.I aio_reqprio +field as an +.B IOPRIO_VALUE +as defined by +.IR linux/ioprio.h. +.RE +.TP .I aio_resfd The file descriptor to signal in the event of asynchronous I/O completion. .SH RETURN VALUE @@ -196,13 +208,21 @@ The AIO context specified by \fIctx_id\fP is invalid. \fInr\fP is less than 0. The \fIiocb\fP at .I *iocbpp[0] -is not properly initialized, -or the operation specified is invalid for the file descriptor -in the \fIiocb\fP. +is not properly initialized, the operation specified is invalid for the file +descriptor in the \fIiocb\fP, or the value in the +.I aio_reqprio +field is invalid. .TP .B ENOSYS .BR io_submit () is not implemented on this architecture. +.TP +.B EPERM +The aio_reqprio field is set with the class +.B IOPRIO_CLASS_RT +, but the submitting context does not have the
What does "submitting context" mean? Threads/tasks/processes have capabilities. Can you rephrase in terms of processes/threads? Thanks, Michael
+.B CAP_SYS_ADMIN +privilege. .SH VERSIONS .PP The asynchronous I/O system calls first appeared in Linux 2.5.
