Date: Tue, 2 Jul 2013 04:42:32 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r252496 - stable/9/sys/dev/drm2/i915 Message-ID: <201307020442.r624gWL9091555@svn.freebsd.org>
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Author: kib Date: Tue Jul 2 04:42:32 2013 New Revision: 252496 URL: http://svnweb.freebsd.org/changeset/base/252496 Log: MFC r251960: Since the gem pagefault handler relocks the vm object lock, other thread might fault on the same GTT offset meantime and instantiate the mapping. Recheck that the mgt device object still does not have a page at the current offset after relocking, and return a possibly installed page. Modified: stable/9/sys/dev/drm2/i915/i915_gem.c Directory Properties: stable/9/sys/ (props changed) stable/9/sys/dev/ (props changed) Modified: stable/9/sys/dev/drm2/i915/i915_gem.c ============================================================================== --- stable/9/sys/dev/drm2/i915/i915_gem.c Tue Jul 2 04:27:16 2013 (r252495) +++ stable/9/sys/dev/drm2/i915/i915_gem.c Tue Jul 2 04:42:32 2013 (r252496) @@ -1371,6 +1371,23 @@ unlocked_vmobj: } else DRM_LOCK(dev); + /* + * Since the object lock was dropped, other thread might have + * faulted on the same GTT address and instantiated the + * mapping for the page. Recheck. + */ + VM_OBJECT_LOCK(vm_obj); + m = vm_page_lookup(vm_obj, OFF_TO_IDX(offset)); + if (m != NULL) { + if ((m->flags & VPO_BUSY) != 0) { + DRM_UNLOCK(dev); + vm_page_sleep(m, "915pee"); + goto retry; + } + goto have_page; + } else + VM_OBJECT_UNLOCK(vm_obj); + /* Now bind it into the GTT if needed */ if (!obj->map_and_fenceable) { ret = i915_gem_object_unbind(obj); @@ -1424,8 +1441,9 @@ unlocked_vmobj: goto retry; } m->valid = VM_PAGE_BITS_ALL; - *mres = m; vm_page_insert(m, vm_obj, OFF_TO_IDX(offset)); +have_page: + *mres = m; vm_page_busy(m); CTR4(KTR_DRM, "fault %p %jx %x phys %x", gem_obj, offset, prot,
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