Re: [Qemu-devel] [PATCH 1/2] blockjob: assert(cb) in the entry functions of blockjob

[Paolo Bonzini]

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.

Paolo