From 661984f4c417a5ccd3b739ad89cfd4b9907f4146 Mon Sep 17 00:00:00 2001 Message-Id: <661984f4c417a5ccd3b739ad89cfd4b9907f4146.1444668695.git.jen@redhat.com> In-Reply-To: <860bcb286a4f0cfcc02e2d5c16c2c94f85fddf12.1444668695.git.jen@redhat.com> References: <860bcb286a4f0cfcc02e2d5c16c2c94f85fddf12.1444668695.git.jen@redhat.com> From: Markus Armbruster Date: Fri, 9 Oct 2015 14:37:30 -0500 Subject: [CHANGE 03/11] memory: allow destroying a non-empty MemoryRegion To: rhvirt-patches@redhat.com, jen@redhat.com RH-Author: Markus Armbruster Message-id: <1444401458-7995-2-git-send-email-armbru@redhat.com> Patchwork-id: 68107 O-Subject: [RHEV-7.2 qemu-kvm-rhev PATCH v2 1/9] memory: allow destroying a non-empty MemoryRegion Bugzilla: 1264347 RH-Acked-by: Igor Mammedov RH-Acked-by: Paolo Bonzini RH-Acked-by: Eduardo Habkost From: Paolo Bonzini This is legal; the MemoryRegion will simply unreference all the existing subregions and possibly bring them down with it as well. However, it requires a bit of care to avoid an infinite loop. Finalizing a memory region cannot trigger an address space update, but memory_region_del_subregion errs on the side of caution and might trigger a spurious update: avoid that by resetting mr->enabled first. Signed-off-by: Paolo Bonzini Signed-off-by: Markus Armbruster Message-Id: <1443689999-12182-2-git-send-email-armbru@redhat.com> (cherry picked from commit 2e2b8eb70fdb7dfbec39f3a19b20f9a73f2f813e) --- memory.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) Signed-off-by: Jeff E. Nelson --- memory.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/memory.c b/memory.c index 7de38a5..85f353f 100644 --- a/memory.c +++ b/memory.c @@ -1312,7 +1312,22 @@ static void memory_region_finalize(Object *obj) { MemoryRegion *mr = MEMORY_REGION(obj); - assert(QTAILQ_EMPTY(&mr->subregions)); + assert(!mr->container); + + /* We know the region is not visible in any address space (it + * does not have a container and cannot be a root either because + * it has no references, so we can blindly clear mr->enabled. + * memory_region_set_enabled instead could trigger a transaction + * and cause an infinite loop. + */ + mr->enabled = false; + memory_region_transaction_begin(); + while (!QTAILQ_EMPTY(&mr->subregions)) { + MemoryRegion *subregion = QTAILQ_FIRST(&mr->subregions); + memory_region_del_subregion(mr, subregion); + } + memory_region_transaction_commit(); + mr->destructor(mr); memory_region_clear_coalescing(mr); g_free((char *)mr->name); -- 2.4.3