Messages in this thread | | | Date | Sat, 14 Jun 2008 00:31:43 +0200 | From | "stephane eranian" <> | Subject | Re: [patch 12/21] perfmon2 minimal: sysfs interface |
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Greg,
On Fri, Jun 13, 2008 at 5:53 AM, Greg KH <greg@kroah.com> wrote: > On Thu, Jun 12, 2008 at 02:54:15PM +0200, stephane eranian wrote: >> >> In any case, let me know if there are still things that must be >> changed/simplified in my file. > > This looks much better. I wonder if you could use the "default" kobject > attributes, which might allow you to remove some of your show/store > wrappers, but in general, it's much better than before. > Well, I wondered about that myself, but I think I am missing one piece. The difference between some of the show/store functions and others is that if you look closely, you see that some make reference to global structures, e.g., pfm_controls, or call out to routines in others modules. For those, I have switched to the default attribute. But the other show/store functions need to access the particular object where the kobj is embedded. And for that, it seems you need to glue function:
#define to_pmu(n) container_of(n, struct pfm_pmu_config, kobj)
static ssize_t pfm_pmu_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct pfm_pmu_config *pmu = to_pmu(kobj); struct pfm_attribute *attribute = to_attr(attr); return attribute->show ? attribute->show(pmu, attribute, buf) : -EIO; }
which basically calls the container_of() routine..
Yet, I get the feeling that is the show routein gets the same kobj, then I could as well do the to_pmu() there. And the attr (use the the strcmp()) would be the default.
If you tell me this is the way to go, I will certainly be happy to make the change and remove even more code!
Thanks.
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