On Wed, 29 Nov 2006 13:50:12 +0000, Christoph Hellwig <[EMAIL PROTECTED]> wrote:
> On Wed, Nov 29, 2006 at 02:08:01PM +0100, S?bastien Dugu? wrote: > > On Wed, 29 Nov 2006 10:51:50 +0000, Christoph Hellwig <[EMAIL PROTECTED]> > > wrote: > > > > > I'm a little bit unhappy about the usage of the notify flag. The usage > > > seems correct but very confusing: > > > > Well, I followed the logic from posix-timers.c, but it may be a poor > > choice ;-) > > > > For a start, the SIGEV_* flags are quite confusing (for me at least). > > SIGEV_SIGNAL is defined as 0, SIGEV_NONE as 1 and SIGEV_THREAD_ID as 4. I > > would rather have seen SIGEV_NONE defined as 0 to avoid all this. > > > > I also wish I knew why those SIGEV_* constants were defined that way. > > Ah, I missed that. It explains some of the more wierd bits. I suspect > we should then use != SIGEV_NONE for the any kind of signal notification > bit and == SIGEV_THREAD_ID for the case where we want to deliver to > a particular thread. Right, that would make things much cleaner. Will try for it. > > But this means we only get a thread reference for SIGEV_THREAD_ID > here: > > > > > + if (notify->notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) { > > > > + /* > > > > + * This reference will be dropped in really_put_req() > > > > when > > > > + * we're done with the request. > > > > + */ > > > > + get_task_struct(target); > > > > + } It's the way it is in posix-timers and I'm not sure I understand why. We take a ref on the specific task if notify is SIGEV_THREAD_ID but not for SIGEV_SIGNAL. I'm wondering what I'm missing here, shouldn't we also take a ref on the task group leader in the SIGEV_SIGNAL case in posix-timers? > > But even use it for SIGEV_SIGNAL without SIGEV_THREAD_ID here: > > > > > + if (notify->notify & SIGEV_THREAD_ID) > > > > + ret = send_sigqueue(notify->signo, sigq, > > > > notify->target); > > > > + else > > > > + ret = send_group_sigqueue(notify->signo, sigq, > > > > notify->target); > > Or do I miss something? I missing something too here ;-) If someone cared to explain why there is no ref taken on the task for the SIGEV_SIGNAL case, it would be much appreciated. Is this a bug in posix-timers? Thanks, Sébastien. - 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/