On Thu, 29 Nov 2007 11:59:06 +0100, Kay Sievers <[EMAIL PROTECTED]> wrote:
> On Thu, 2007-11-29 at 11:05 +0100, Cornelia Huck wrote: > > On Wed, 28 Nov 2007 17:00:57 -0500 (EST), > > Alan Stern <[EMAIL PROTECTED]> wrote: > > > On Wed, 28 Nov 2007, Greg KH wrote: > > > > On Wed, Nov 28, 2007 at 03:42:00PM -0500, Alan Stern wrote: > > > > > This patch (as1020) adds a check to kobject_init() to insure that the > > > > > ktype field is not NULL. This is just for safety's sake; as far as I > > > > > know there are no remaining places where the field is left unset. But > > > > > ironically, kset_init() did fail to set it! The patch fixes that and > > > > > removes some redundant initialization in kset_createa(). > > > > > > > > > > The patch also fixes up elevator_init(), where ktype was set after > > > > > calling kobject_init() instead of before. > > > > > > > > No, it's safe to set ktype after kobject_init, it was just not safe to > > > > set the kset. As Kay pointed out, I just added a patch to my tree to > > > > resolve this issue, and I'll go back and update the documentation now. > > > > > > > > I do like the "check for a ktype" warning, I'll go add that to my local > > > > tree and see what breaks. Odds are, all the static kobjects will :( > > > > > > You have to be careful. The ktype check I wrote lives in > > > kobject_init() -- that's why I had to make elevator_init() assign the > > > ktype before calling kobject_init(). If you put the check into > > > kobject_add() instead then you won't end up checking objects that get > > > initialized but not added. > > > > > > Yes, nobody would deliberately use a kobject without adding it, but it > > > could happen as the result of an failure between the _init and _add > > > calls. > > > > And if someone calls kobject_put() after kobject_init() to clean up, > > their release function will not be called if they didn't set the ktype. > > So the check really belongs into kobject_init() IMO. > > Hmm, will one expect that the whole object will also be free'd when we > suggest to call kobject_put() to cleanup? That might be pretty > unexpected, right? I'd expect the kobject to be freed if I called kobject_put() on my last reference (but that may be because I'm familiar with the code :)). OTOH, if getting the reference on the kset is moved from kobject_init() to kobject_add(), we aren't forced to use kobject_put() but may use kfree(). - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
