Re: [Qemu-devel] [PATCH] aio-posix: fill error message that is missed

[Fam Zheng <famz@redhat.com>]

On Tue, 07/12 09:41, Eric Blake wrote:
> On 07/12/2016 05:34 AM, Cao jin wrote:
> > The current judegement of caller is meaningless, make it useful.
> 
> Is this something you can trigger? If so, what command line?  If not,
> how did you find it?
> 
> Spelled 'judgment', not 'judegement'; but rather than just fixing the
> typo, it might read better as:
> 
> The lone caller of aio_context_setup() only checks whether an error was
> set, but aio_context_setup() is not setting an error.
> 
> > 
> > Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
> > ---
> >  aio-posix.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/aio-posix.c b/aio-posix.c
> > index 6006122..8b0deb7 100644
> > --- a/aio-posix.c
> > +++ b/aio-posix.c
> > @@ -18,6 +18,7 @@
> >  #include "block/block.h"
> >  #include "qemu/queue.h"
> >  #include "qemu/sockets.h"
> > +#include "qapi/error.h"
> >  #ifdef CONFIG_EPOLL_CREATE1
> >  #include <sys/epoll.h>
> >  #endif
> > @@ -491,6 +492,7 @@ void aio_context_setup(AioContext *ctx, Error **errp)
> >      assert(!ctx->epollfd);
> >      ctx->epollfd = epoll_create1(EPOLL_CLOEXEC);
> >      if (ctx->epollfd == -1) {
> > +        error_setg_errno(errp, errno, "Failed to create epoll instance");
> >          ctx->epoll_available = false;
> >      } else {
> >          ctx->epoll_available = true;
> 
> However, I'm not even sure your patch is right.  The mere fact that we
> have ctx->epoll_available makes it sound like we WANT to be able to
> gracefully fall back when epoll is not available, rather than raising an
> error message.

Yes. This patch doesn't make sense to me. What can be done is 1) remove errp
parameter as it's not used; 2) fprintf(stderr, ...) or error_report(....) here
if epoll_create1 failed.

Fam