[src/trunk]: src/sys/dev Fix broken logic with regard to the use of uvm_unmap...

[nat <nat%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8e5d5cb0a5cf
branches:  trunk
changeset: 824096:8e5d5cb0a5cf
user:      nat <nat%NetBSD.org@localhost>
date:      Tue May 23 07:57:26 2017 +0000

description:
Fix broken logic with regard to the use of uvm_unmap.  Call uvm_unmap with
the correct arguments.

Ok chs@.

diffstat:

 sys/dev/audio.c |  33 ++++++++++++++++++---------------
 1 files changed, 18 insertions(+), 15 deletions(-)

diffs (76 lines):

diff -r 2f82a299c6a0 -r 8e5d5cb0a5cf sys/dev/audio.c
--- a/sys/dev/audio.c   Tue May 23 07:13:11 2017 +0000
+++ b/sys/dev/audio.c   Tue May 23 07:57:26 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.351 2017/05/16 23:55:53 nat Exp $  */
+/*     $NetBSD: audio.c,v 1.352 2017/05/23 07:57:26 nat Exp $  */
 
 /*-
  * Copyright (c) 2016 Nathanial Sloss <nathanialsloss%yahoo.com.au@localhost>
@@ -148,7 +148,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.351 2017/05/16 23:55:53 nat Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.352 2017/05/23 07:57:26 nat Exp $");
 
 #include "audio.h"
 #if NAUDIO > 0
@@ -1191,9 +1191,8 @@
        if (bufsize < AUMINBUF)
                bufsize = AUMINBUF;
        ROUNDSIZE(bufsize);
-       if (hw->round_buffersize) {
+       if (hw->round_buffersize)
                bufsize = hw->round_buffersize(hdl, direction, bufsize);
-       }
 
        if (hw->allocm && (r == &chan->vc->sc_mpr || r == &chan->vc->sc_mrr)) {
                /* Hardware ringbuffer.  No dedicated uvm object.*/
@@ -1215,16 +1214,16 @@
                error = uvm_map(kernel_map, &vstart, vsize, r->uobj, 0, 0,
                    UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, UVM_INH_NONE,
                        UVM_ADV_RANDOM, 0));
-               if (error)
-                       goto bad_map;
+               if (error) {
+                       uao_detach(r->uobj);    /* release reference */
+                       r->uobj = NULL;         /* paranoia */
+                       return error;
+               }
 
                error = uvm_map_pageable(kernel_map, vstart, vstart + vsize,
                    false, 0);
-
                if (error) {
-                       uvm_unmap(kernel_map, vstart, vsize);
-bad_map:
-                       uao_detach(r->uobj);    /* release reference */
+                       uvm_unmap(kernel_map, vstart, vstart + vsize);
                        r->uobj = NULL;         /* paranoia */
                        return error;
                }
@@ -1254,14 +1253,18 @@
                KASSERT(r->uobj == NULL);
                sc->hw_if->freem(sc->hw_hdl, r->s.start, r->s.bufsize);
        } else {
-                               /* Software ringbuffer.  */
+               /* Software ringbuffer.  */
                vstart = (vaddr_t)r->s.start;
                vsize = roundup2(MAX(r->s.bufsize, PAGE_SIZE), PAGE_SIZE);
 
-               uvm_map_pageable(kernel_map, vstart, vstart + vsize,
-                   true, 0);
-               uvm_unmap(kernel_map, vstart, vsize);
-               uao_detach(r->uobj);    /* release reference */
+               /*
+                * Unmap the kernel mapping.  uvm_unmap releases the
+                * reference to the uvm object, and this should be the
+                * last virtual mapping of the uvm object, so no need
+                * to explicitly release (`detach') the object.
+                */
+               uvm_unmap(kernel_map, vstart, vstart + vsize);
+
                r->uobj = NULL;         /* paranoia */
        }