[src/trunk]: src/sys/external/bsd/drm2/linux Linux work is queued in intr con...

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

details:   https://anonhg.NetBSD.org/src/rev/fce3e49bd6ad
branches:  trunk
changeset: 797790:fce3e49bd6ad
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Jul 27 14:02:48 2014 +0000

description:
Linux work is queued in intr context, so block intrs when locking.

(Yes, this getting out of hand.)

diffstat:

 sys/external/bsd/drm2/linux/linux_work.c |  29 +++++++++++++++++++++++++++--
 1 files changed, 27 insertions(+), 2 deletions(-)

diffs (68 lines):

diff -r 4f53d7e051fe -r fce3e49bd6ad sys/external/bsd/drm2/linux/linux_work.c
--- a/sys/external/bsd/drm2/linux/linux_work.c  Sun Jul 27 10:19:12 2014 +0000
+++ b/sys/external/bsd/drm2/linux/linux_work.c  Sun Jul 27 14:02:48 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_work.c,v 1.5 2014/07/25 16:15:12 riastradh Exp $ */
+/*     $NetBSD: linux_work.c,v 1.6 2014/07/27 14:02:48 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_work.c,v 1.5 2014/07/25 16:15:12 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_work.c,v 1.6 2014/07/27 14:02:48 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -281,24 +281,49 @@
  *
  * We use __cpu_simple_lock(9) rather than mutex(9) because Linux code
  * does not destroy work, so there is nowhere to call mutex_destroy.
+ *
+ * XXX This is getting out of hand...  Really, work items shouldn't
+ * have locks in them at all; instead the workqueues should.
  */
 
 static void
 linux_work_lock_init(struct work_struct *work)
 {
+
        __cpu_simple_lock_init(&work->w_lock);
 }
 
 static void
 linux_work_lock(struct work_struct *work)
 {
+       struct cpu_info *ci;
+       int cnt, s;
+
+       /* XXX Copypasta of MUTEX_SPIN_SPLRAISE.  */
+       s = splvm();
+       ci = curcpu();
+       cnt = ci->ci_mtx_count--;
+       __insn_barrier();
+       if (cnt == 0)
+               ci->ci_mtx_oldspl = s;
+
        __cpu_simple_lock(&work->w_lock);
 }
 
 static void
 linux_work_unlock(struct work_struct *work)
 {
+       struct cpu_info *ci;
+       int s;
+
        __cpu_simple_unlock(&work->w_lock);
+
+       /* XXX Copypasta of MUTEX_SPIN_SPLRESTORE.  */
+       ci = curcpu();
+       s = ci->ci_mtx_oldspl;
+       __insn_barrier();
+       if (++ci->ci_mtx_count == 0)
+               splx(s);
 }
 
 static bool __diagused