2019年5月2日(木) 21:47 Johannes Berg <johan...@sipsolutions.net>:
>
> On Thu, 2019-05-02 at 17:59 +0900, Akinobu Mita wrote:
> >
> > static void devcd_del(struct work_struct *wk)
> > {
> > struct devcd_entry *devcd;
> > + int i;
> >
> > devcd = container_of(wk, struct devcd_entry, del_wk.work);
> >
> > + for (i = 0; i < devcd->num_files; i++) {
> > + device_remove_bin_file(&devcd->devcd_dev,
> > + &devcd->files[i].bin_attr);
> > + }
>
> Not much value in the braces?
OK. I tend to use braces where a single statement but multiple lines.
> > +static struct devcd_entry *devcd_alloc(struct dev_coredumpm_bulk_data
> > *files,
> > + int num_files, gfp_t gfp)
> > +{
> > + struct devcd_entry *devcd;
> > + int i;
> > +
> > + devcd = kzalloc(sizeof(*devcd), gfp);
> > + if (!devcd)
> > + return NULL;
> > +
> > + devcd->files = kcalloc(num_files, sizeof(devcd->files[0]), gfp);
> > + if (!devcd->files) {
> > + kfree(devcd);
> > + return NULL;
> > + }
> > + devcd->num_files = num_files;
>
> IMHO it would be nicer to allocate all of this in one struct, i.e. have
>
> struct devcd_entry {
> ...
> struct devcd_file files[];
> }
>
> (and then use struct_size())
Sounds good.
> > @@ -309,7 +339,41 @@ void dev_coredumpm(struct device *dev, struct module
> > *owner,
> > put_module:
> > module_put(owner);
> > free:
> > - free(data);
> > + for (i = 0; i < num_files; i++)
> > + files[i].free(files[i].data);
> > +}
>
> and then you don't need to do all this kind of thing to free
>
> Otherwise looks fine. I'd worry a bit that existing userspace will only
> capture the 'data' file, rather than a tarball of all files, but I guess
> that's something you'd have to work out then when actually desiring to
> use multiple files.
Your worrying is correct. I'm going to create a empty 'data' file for nvme
coredump. Assuming that devcd* always contains the 'data' file at least,
we can simply write to 'data' when the device coredump is no longer needed,
and prepare for the newer coredump.
