From fc9c9ab22d5650977c417ef2032d02f455011b23 Mon Sep 17 00:00:00 2001 From: Bharath Ramesh <bramesh@vt.edu> Date: Sat, 16 Apr 2005 15:25:41 -0700 Subject: [PATCH] [PATCH] AYSNC IO using singals other than SIGIO A question on sigwaitinfo based IO mechanism in multithreaded applications. I am trying to use RT signals to notify me of IO events using RT signals instead of SIGIO in a multithreaded applications. I noticed that there was some discussion on lkml during november 1999 with the subject of the discussion as "Signal driven IO". In the thread I noticed that RT signals were being delivered to the worker thread. I am running 2.6.10 kernel and I am trying to use the very same mechanism and I find that only SIGIO being propogated to the worker threads and RT signals only being propogated to the main thread and not the worker threads where I actually want them to be propogated too. On further inspection I found that the following patch which I have attached solves the problem. I am not sure if this is a bug or feature in the kernel. Roland McGrath <roland@redhat.com> said: This relates only to fcntl F_SETSIG, which is a Linux extension. So there is no POSIX issue. When changing various things like the normal SIGIO signalling to do group signals, I was concerned strictly with the POSIX semantics and generally avoided touching things in the domain of Linux inventions. That's why I didn't change this when I changed the call right next to it. There is no reason I can see that F_SETSIG-requested signals shouldn't use a group signal like normal SIGIO does. I'm happy to ACK this patch, there is nothing wrong with its change to the semantics in my book. But neither POSIX nor I care a whit what F_SETSIG does. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> --- fs/fcntl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index c1708066bf55d..3e7ab16ed1547 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -437,7 +437,7 @@ static void send_sigio_to_task(struct task_struct *p, else si.si_band = band_table[reason - POLL_IN]; si.si_fd = fd; - if (!send_sig_info(fown->signum, &si, p)) + if (!send_group_sig_info(fown->signum, &si, p)) break; /* fall-through: fall back on the old plain SIGIO signal */ case 0: -- GitLab