[src/trunk]: src/sys/external/bsd/drm2 Drop take the {ttm, gem} vmobjlock in t...

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

details:   https://anonhg.NetBSD.org/src/rev/f6b535b22e66
branches:  trunk
changeset: 331702:f6b535b22e66
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Aug 20 13:48:08 2014 +0000

description:
Drop take the {ttm,gem} vmobjlock in the fault handler.

- We don't need this lock.
- uvm does nothing between taking it and calling the fault handler.
- Now that the uvm_aobj shares vmobjlock with the {ttm,gem} uvm
  object, we must not hold the lock when we call uvm_obj_wirepages on
  the uvm_aobj.

XXX pullup to netbsd-7

diffstat:

 sys/external/bsd/drm2/dist/drm/i915/i915_gem.c |   4 ++++
 sys/external/bsd/drm2/ttm/ttm_bo_vm.c          |  10 +++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diffs (59 lines):

diff -r 7485c0e76686 -r f6b535b22e66 sys/external/bsd/drm2/dist/drm/i915/i915_gem.c
--- a/sys/external/bsd/drm2/dist/drm/i915/i915_gem.c    Wed Aug 20 13:29:07 2014 +0000
+++ b/sys/external/bsd/drm2/dist/drm/i915/i915_gem.c    Wed Aug 20 13:48:08 2014 +0000
@@ -1842,6 +1842,9 @@
 
        intel_runtime_pm_get(dev_priv);
 
+       /* Thanks, uvm, but we don't need this lock.  */
+       mutex_exit(uobj->vmobjlock);
+
        ret = i915_mutex_lock_interruptible(dev);
        if (ret)
                goto out;
@@ -1880,6 +1883,7 @@
 unlock:
        mutex_unlock(&dev->struct_mutex);
 out:
+       mutex_enter(uobj->vmobjlock);
        uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);
        if (ret == -ERESTART)
                uvm_wait("i915flt");
diff -r 7485c0e76686 -r f6b535b22e66 sys/external/bsd/drm2/ttm/ttm_bo_vm.c
--- a/sys/external/bsd/drm2/ttm/ttm_bo_vm.c     Wed Aug 20 13:29:07 2014 +0000
+++ b/sys/external/bsd/drm2/ttm/ttm_bo_vm.c     Wed Aug 20 13:48:08 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ttm_bo_vm.c,v 1.3 2014/08/18 01:17:34 riastradh Exp $  */
+/*     $NetBSD: ttm_bo_vm.c,v 1.4 2014/08/20 13:48:08 riastradh Exp $  */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ttm_bo_vm.c,v 1.3 2014/08/18 01:17:34 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ttm_bo_vm.c,v 1.4 2014/08/20 13:48:08 riastradh Exp $");
 
 #include <sys/types.h>
 
@@ -92,6 +92,9 @@
        unsigned mmapflags;
        int ret;
 
+       /* Thanks, uvm, but we don't need this lock.  */
+       mutex_exit(uobj->vmobjlock);
+
        /* Copy-on-write mappings make no sense for the graphics aperture.  */
        if (UVM_ET_ISCOPYONWRITE(ufi->entry)) {
                ret = -EIO;
@@ -199,7 +202,8 @@
 out3:  pmap_update(ufi->orig_map->pmap);
 out2:  ttm_mem_io_unlock(man);
 out1:  ttm_bo_unreserve(bo);
-out0:  uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);
+out0:  mutex_enter(uobj->vmobjlock);
+       uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);
        /* XXX errno Linux->NetBSD */
        return -ret;
 }