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authorBharath Ramesh <bramesh@vt.edu>2005-04-16 18:25:41 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:25:41 -0400
commitfc9c9ab22d5650977c417ef2032d02f455011b23 (patch)
tree27f9827f559cb732c78bb713e097c8a023e76768 /fs
parent4a534f93b371e8e6e87ae302757365f0f583e06b (diff)
[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>
Diffstat (limited to 'fs')
-rw-r--r--fs/fcntl.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index c1708066bf55..3e7ab16ed154 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -437,7 +437,7 @@ static void send_sigio_to_task(struct task_struct *p,
437 else 437 else
438 si.si_band = band_table[reason - POLL_IN]; 438 si.si_band = band_table[reason - POLL_IN];
439 si.si_fd = fd; 439 si.si_fd = fd;
440 if (!send_sig_info(fown->signum, &si, p)) 440 if (!send_group_sig_info(fown->signum, &si, p))
441 break; 441 break;
442 /* fall-through: fall back on the old plain SIGIO signal */ 442 /* fall-through: fall back on the old plain SIGIO signal */
443 case 0: 443 case 0: