svn commit: r315089 - head/share/man/man9
Ian Lepore
ian at FreeBSD.org
Sat Mar 11 22:22:52 UTC 2017
Author: ian
Date: Sat Mar 11 22:22:51 2017
New Revision: 315089
URL: https://svnweb.freebsd.org/changeset/base/315089
Log:
Document uiomove_frombuf(9).
Modified:
head/share/man/man9/Makefile
head/share/man/man9/uio.9
Modified: head/share/man/man9/Makefile
==============================================================================
--- head/share/man/man9/Makefile Sat Mar 11 20:28:31 2017 (r315088)
+++ head/share/man/man9/Makefile Sat Mar 11 22:22:51 2017 (r315089)
@@ -1843,6 +1843,7 @@ MLINKS+=uidinfo.9 uifind.9 \
uidinfo.9 uihashinit.9 \
uidinfo.9 uihold.9
MLINKS+=uio.9 uiomove.9 \
+ uio.9 uiomove_frombuf.9 \
uio.9 uiomove_nofault.9
.if ${MK_USB} != "no"
Modified: head/share/man/man9/uio.9
==============================================================================
--- head/share/man/man9/uio.9 Sat Mar 11 20:28:31 2017 (r315088)
+++ head/share/man/man9/uio.9 Sat Mar 11 22:22:51 2017 (r315089)
@@ -25,12 +25,13 @@
.\"
.\" $FreeBSD$
.\"
-.Dd January 19, 2012
+.Dd March 11, 2017
.Dt UIO 9
.Os
.Sh NAME
.Nm uio ,
.Nm uiomove ,
+.Nm uiomove_frombuf ,
.Nm uiomove_nofault
.Nd device driver I/O routines
.Sh SYNOPSIS
@@ -50,10 +51,13 @@ struct uio {
.Ft int
.Fn uiomove "void *buf" "int howmuch" "struct uio *uiop"
.Ft int
+.Fn uiomove_frombuf "void *buf" "int howmuch" "struct uio *uiop"
+.Ft int
.Fn uiomove_nofault "void *buf" "int howmuch" "struct uio *uiop"
.Sh DESCRIPTION
The functions
-.Fn uiomove
+.Fn uiomove ,
+.Fn uiomove_frombuf ,
and
.Fn uiomove_nofault
are used to transfer data between buffers and I/O vectors that might
@@ -129,9 +133,27 @@ Thus, the function
.Fn uiomove_nofault
can be called from contexts where acquiring virtual memory system
locks or sleeping are prohibited.
+.Pp
+The
+.Fn uiomove_frombuf
+function is a convenience wrapper around
+.Fn uiomove
+for drivers that serve data which is wholly contained within an
+existing buffer in memory.
+It validates the
+.Va uio_offset
+and
+.Va uio_resid
+values against the size of the existing buffer, handling short
+transfers when the request partially overlaps the buffer.
+When
+.Va uio_offset
+is greater than or equal to the buffer size, the result is success
+with no bytes transfered, effectively signaling EOF.
.Sh RETURN VALUES
On success
-.Fn uiomove
+.Fn uiomove ,
+.Fn uiomove_frombuf ,
and
.Fn uiomove_nofault
will return 0; on error they will return an appropriate error code.
More information about the svn-src-head
mailing list