[Qemu-devel] [PULL 16/40] ivshmem: Fix harmless misuse of Error

[Markus Armbruster <armbru@redhat.com>]

We reuse errp after passing it host_memory_backend_get_memory().  If
both host_memory_backend_get_memory() and the reuse set an error, the
reuse will fail the assertion in error_setv().  Fortunately,
host_memory_backend_get_memory() can't fail.

Pass it &error_abort to make our assumption explicit, and to get the
assertion failure in the right place should it become invalid.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-17-git-send-email-armbru@redhat.com>
---
 hw/misc/ivshmem.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 0ac0238..299cf5b 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -842,7 +842,7 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp)
             g_warning("size argument ignored with hostmem");
         }
 
-        mr = host_memory_backend_get_memory(s->hostmem, errp);
+        mr = host_memory_backend_get_memory(s->hostmem, &error_abort);
         s->ivshmem_size = memory_region_size(mr);
     } else if (s->sizearg == NULL) {
         s->ivshmem_size = 4 << 20; /* 4 MB default */
@@ -907,7 +907,8 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp)
 
         IVSHMEM_DPRINTF("using hostmem\n");
 
-        mr = host_memory_backend_get_memory(MEMORY_BACKEND(s->hostmem), errp);
+        mr = host_memory_backend_get_memory(MEMORY_BACKEND(s->hostmem),
+                                            &error_abort);
         vmstate_register_ram(mr, DEVICE(s));
         memory_region_add_subregion(&s->bar, 0, mr);
         pci_register_bar(PCI_DEVICE(s), 2, attr, &s->bar);
@@ -1134,7 +1135,7 @@ static void ivshmem_check_memdev_is_busy(Object *obj, const char *name,
 {
     MemoryRegion *mr;
 
-    mr = host_memory_backend_get_memory(MEMORY_BACKEND(val), errp);
+    mr = host_memory_backend_get_memory(MEMORY_BACKEND(val), &error_abort);
     if (memory_region_is_mapped(mr)) {
         char *path = object_get_canonical_path_component(val);
         error_setg(errp, "can't use already busy memdev: %s", path);
-- 
2.4.3