Re: [Qemu-devel] [PATCH] pci: Set err to errp directly rather than through error_porpagate()

[Mao Zhongyi]

Hi, Markus

On 05/26/2017 05:43 PM, Igor Mammedov wrote:

On Fri, 26 May 2017 16:29:25 +0800
Mao Zhongyi <maozy.f...@cn.fujitsu.com> wrote:

ioh3420_interrupts_init() and its callers, rp_realize() and
pci_qdev_realize() fill error message to local_err, then
propagate it to errp by error_porpagate(), which's not necessary.
So eliminate it and pass errp directly instead of local_err.
Of course, error_propagate() also will be removed.

Signed-off-by: Mao Zhongyi <maozy.f...@cn.fujitsu.com>
---

[...]

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 98ccc27..0d4a3ff 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1982,7 +1982,6 @@ static void pci_qdev_realize(DeviceState *qdev, Error 
**errp)
 {
     PCIDevice *pci_dev = (PCIDevice *)qdev;
     PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(pci_dev);
-    Error *local_err = NULL;
     PCIBus *bus;
     bool is_default_rom;

@@ -1999,9 +1998,8 @@ static void pci_qdev_realize(DeviceState *qdev, Error 
**errp)
         return;

     if (pc->realize) {
-        pc->realize(pci_dev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        pc->realize(pci_dev, errp);
+        if (errp && *errp) {
             do_pci_unregister_device(pci_dev);
             return;
         }
@@ -2014,9 +2012,8 @@ static void pci_qdev_realize(DeviceState *qdev, Error 
**errp)
         is_default_rom = true;
     }

-    pci_add_option_rom(pci_dev, is_default_rom, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    pci_add_option_rom(pci_dev, is_default_rom, errp);
+    if (errp && *errp) {
         pci_qdev_unrealize(DEVICE(pci_dev), NULL);
         return;
     }

dropping local_error here looks wrong since it's used
to check error status inside these functions and to undo
side effects in case of failure.

consider if caller pass errp = NULL
then error handling path won't be executed.

Thanks for you detailed explanation, I ignored this question
actually. The specified error message will not be converted to
Error. Because error handling function returned directly when
caller pass errp = NULL, right?

So keep the rest of the patch but drop above hunks.

I will drop this part of wrong process and commit the next
version right away.

Thanks a lot.
Mao