Document uvm_vslock_device(9) and its DMA-reachable dance.

2 files changed, 24 insertions, 11 deletions

diff --git a/share/man/man9/physio.9 b/share/man/man9/physio.9
index c5ac534224e..ce60bcb2ef6 100644
--- a/share/man/man9/physio.9
+++ b/share/man/man9/physio.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: physio.9,v 1.9 2019/12/06 10:33:04 mpi Exp $
+.\"	$OpenBSD: physio.9,v 1.10 2019/12/06 11:09:47 mpi Exp $
 .\"	$NetBSD: physio.9,v 1.5 1999/03/16 00:40:47 garbled Exp $
 .\"
 .\" Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -64,9 +64,9 @@ needs to lock the appropriate data area into memory before each transaction
 with
 .Fa strategy
 (see
-.Xr uvm_vslock 9
+.Xr uvm_vslock_device 9
 and
-.Xr uvm_vsunlock 9 ) .
+.Xr uvm_vsunlock_device 9 ) .
 .Fn physio
 always awaits the completion of the entire requested transfer before
 returning, unless an error condition is detected earlier.
diff --git a/share/man/man9/uvm_vslock.9 b/share/man/man9/uvm_vslock.9
index c7f1fb88565..b1bbb6d9dab 100644
--- a/share/man/man9/uvm_vslock.9
+++ b/share/man/man9/uvm_vslock.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: uvm_vslock.9,v 1.1 2019/12/06 10:42:33 mpi Exp $
+.\"	$OpenBSD: uvm_vslock.9,v 1.2 2019/12/06 11:09:47 mpi Exp $
 .\"	$NetBSD: uvm.9,v 1.14 2000/06/29 06:08:44 mrg Exp $
 .\"
 .\" Copyright (c) 1998 Matthew R. Green
@@ -30,7 +30,9 @@
 .Os
 .Sh NAME
 .Nm uvm_vslock ,
-.Nm uvm_vsunlock
+.Nm uvm_vsunlock ,
+.Nm uvm_vslock_device ,
+.Nm uvm_vsunlock_device
 .Nd wire user memory for I/O
 .Sh SYNOPSIS
 .In uvm/uvm_extern.h
@@ -39,12 +41,16 @@
                "vm_prot_t access_type"
 .Ft void
 .Fn uvm_vsunlock "struct proc *p" "caddr_t addr" "size_t len"
+.Ft int
+.Fn uvm_vslock_device "struct proc *p" "void *addr" "size_t len" \
+               "vm_prot_t access_type" "void **retp"
+.Ft void
+.Fn uvm_vsunlock_device "struct proc *p" "void *addr" "size_t len" "void *map"
 .Sh DESCRIPTION
 The
 .Fn uvm_vslock
-and
-.Fn uvm_vsunlock
-functions control the wiring and unwiring of pages for process
+family of functions
+control the wiring and unwiring of pages for process
 .Fa p
 from
 .Fa addr
@@ -52,9 +58,16 @@ to
 .Fa addr + len .
 The
 .Fa access_type
-argument of
-.Fn uvm_vslock
-is passed to
+argument is passed to
 .Xr uvm_fault 9 .
+.Pp
+.Fn uvm_vslock_device
+also checks if the pages are DMA reachable.
+When they aren't, it bounces their content into a newly created mapping
+returned in
+.Fa retp .
+.Fn uvm_vsunlock_device
+will release this memory mapping pointed by
+.Fa map .
 .Sh SEE ALSO
 .Xr uvm_fault 9