Messages in this thread | | | From | Phillip Potter <> | Subject | Re: [PATCH v2] drivers/cdrom: improved ioctl for media change detection | Date | Thu, 9 Sep 2021 01:17:21 +0100 |
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> > +static int cdrom_ioctl_timed_media_change(struct cdrom_device_info *cdi, > > + unsigned long arg) > > +{ > > + int ret; > > + struct cdrom_timed_media_change_info __user *info; > > + struct cdrom_timed_media_change_info tmp_info; > > + > > + if (!CDROM_CAN(CDC_MEDIA_CHANGED)) > > + return -ENOSYS; > > + > > + info = (struct cdrom_timed_media_change_info __user *)arg; > > + cd_dbg(CD_DO_IOCTL, "entering CDROM_TIMED_MEDIA_CHANGE\n"); > > + > > + ret = cdrom_ioctl_media_changed(cdi, CDSL_CURRENT); > > + if (ret < 0) > > + return ret; > > + > > + if (copy_from_user(&tmp_info, info, sizeof(tmp_info)) != 0) > > + return -EFAULT; > > + > > + tmp_info.has_changed = ((tmp_info.last_media_change - cdi->last_media_change_ms) < 0); > Dear Christoph,
Sorry didn't see this e-mail before I replied to Lukas, so I hope you don't think I was ignoring you :-)
> Overly long line here, but more importantly this is much cleaner with > a good old if: > > > if (tmp_info.last_media_change - cdi->last_media_change_ms) < 0) > tmp_info.has_changed = 1; >
Whilst I don't disagree this is technically cleaner, the existing style certainly read well to me. In terms of line length, checkpatch doesn't complain about it, so I guess you mean purely from a visual perspective?
> > +{ > > + __s64 last_media_change; /* Timestamp of the last detected media > > + * change in ms. May be set by caller, updated > > + * upon successful return of ioctl. > > + */ > > + __u64 has_changed; /* Set to 1 by ioctl if last detected media > > More overly long lines. Also why is has_changed a u64 if it is used as > a boolean flag?
As this is not a packed struct, would not a smaller value still take up the same space?
As I'm keen to grow as a maintainer and take feedback, I can certainly wait for Lukas to reply to this for sure.
Regards, Phil
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