Re: [Qemu-devel] [RFC][PATCH] qemu_opt_get_bool_helper: back finding desc by name just if !opt->desc

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Tue, Jan 06, 2015 at 10:39:13AM +0800, Chen, Tiejun wrote:
> On 2015/1/6 9:21, Chen, Tiejun wrote:
> >On 2015/1/6 1:13, Eric Blake wrote:
> >>On 01/04/2015 10:35 PM, Tiejun Chen wrote:
> >>>After one commit 49d2e648e808, "machine: remove qemu_machine_opts
> >>>global list", is introduced, QEMU doesn't keep a global list of
> >>>options but set desc lately. Then we can see the following,
> >>>
> >>>$ x86_64-softmmu/qemu-system-x86_64 -usb
> >>>qemu-system-x86_64: util/qemu-option.c:387: qemu_opt_get_bool_helper: \
> >>>     Assertion `opt->desc && opt->desc->type == QEMU_OPT_BOOL' failed.
> >>>Aborted (core dumped)
> >>>
> >>>So inside qemu_opt_get_bool_helper, we need to call find_desc_by_name()
> >>>to work parse_option_bool() out just in case of !opt->desc.
> >>>
> >>>Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> >>>---
> >>>  util/qemu-option.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>>diff --git a/util/qemu-option.c b/util/qemu-option.c
> >>>index a708241..7cb3601 100644
> >>>--- a/util/qemu-option.c
> >>>+++ b/util/qemu-option.c
> >>>@@ -377,7 +377,7 @@ static bool qemu_opt_get_bool_helper(QemuOpts
> >>>*opts, const char *name,
> >>>      }
> >>>
> >>>      opt = qemu_opt_find(opts, name);
> >>>-    if (opt == NULL) {
> >>>+    if ((opt == NULL) || !opt->desc)  {
> >>
> >>Over-parenthesized, and looks like you also introduced a spurious space.
> >>  Simpler to just have:
> >>
> >>if (!opt || !opt->desc) {
> >
> >Looks good.
> >
> >>
> >>Also, there are other threads about the same topic.
> >>https://lists.gnu.org/archive/html/qemu-devel/2015-01/msg00130.html
> >
> >Yeah, I already notice that.
> >
> 
> Then I realize I need to extend this to all qemu_opt_get_*.

Marcel is working on a fix.

I think hacking qemu_opt_get_* is not a clean solution.  The intention
was to move away from QemuOpts to QOM properties.  The patch that
removed -machine QemuOptsList descriptions was buggy, but the proper fix
is to make that approach work instead of hacking qemu_opt_get_*.

Stefan

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