|
From: | Changlong Xie |
Subject: | Re: [Qemu-devel] [PATCH 1/2] blockjob: assert(cb) in the entry functions of blockjob |
Date: | Thu, 23 Jun 2016 09:04:08 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 06/23/2016 01:31 AM, Eric Blake wrote:
On 06/22/2016 04:19 AM, Paolo Bonzini wrote:On 22/06/2016 12:12, Changlong Xie wrote:commit/mirror/stream/backup use block_job_create(..., cb,..) to create relevant blockjob. When they finished, these jobs will invoke block_job_completed, then invoke job->cb() unconditionally. So i think we need this to avoid segment fault. Actually backup has implemented this.So this suggests that the right place to put the assertion would be block_job_create. But it's even better to add a #define QEMU_NONNULL __attribute__((__nonnull__)) to include/qemu/compiler.h and declare the arguments as non-null.Or alternatively fix things to only invoke job->cb() if it is non-NULL, so that callers don't have to pass in a no-op callback just to appease a non-NULL attribute.
Is there any reason, that we should invoke job->cb() unconditionally without nonnull check? There is no relevant clue in the historical commit messages. If yes, i prefer paolo's suggestion; otherwise eric's solution is better.
Thanks -Xie
[Prev in Thread] | Current Thread | [Next in Thread] |