From: Gregory Haskins <ghaskins@novell.com>
To: davidel@xmailserver.org
Cc: mst@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, avi@redhat.com,
paulmck@linux.vnet.ibm.com, mingo@elte.hu
Subject: [PATCH 1/3] eventfd: Allow waiters to be notified about the eventfd file* going away
Date: Fri, 19 Jun 2009 14:51:27 -0400 [thread overview]
Message-ID: <20090619185127.31118.2893.stgit@dev.haskins.net> (raw)
In-Reply-To: <20090619183534.31118.30934.stgit@dev.haskins.net>
From: Davide Libenzi <davidel@xmailserver.org>
And give them a change to unregister from the wait queue.
This is turn allows eventfd users to use the eventfd file* w/out holding a
live reference to it.
After the eventfd user callbacks returns, any usage of the eventfd file*
should be dropped. The eventfd user callback can acquire sleepy locks
since it is invoked lockless.
This is a feature, needed by KVM to avoid an awkward workaround when using
eventfd.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Tested-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
fs/eventfd.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 2a701d5..c71f51d 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -59,7 +59,15 @@ int eventfd_signal(struct file *file, int n)
static int eventfd_release(struct inode *inode, struct file *file)
{
- kfree(file->private_data);
+ struct eventfd_ctx *ctx = file->private_data;
+
+ /*
+ * No need to hold the lock here, since we are on the file cleanup
+ * path and the ones still attached to the wait queue will be
+ * serialized by wake_up_locked_poll().
+ */
+ wake_up_locked_poll(&ctx->wqh, POLLHUP);
+ kfree(ctx);
return 0;
}
next prev parent reply other threads:[~2009-06-19 18:52 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 2:29 [KVM-RFC PATCH 0/2] eventfd enhancements for irqfd/iosignalfd Gregory Haskins
2009-06-16 2:29 ` [KVM-RFC PATCH 1/2] eventfd: add an explicit srcu based notifier interface Gregory Haskins
2009-06-16 14:02 ` Michael S. Tsirkin
2009-06-16 14:11 ` Gregory Haskins
2009-06-16 14:38 ` Michael S. Tsirkin
2009-06-16 14:48 ` Gregory Haskins
2009-06-16 14:54 ` Gregory Haskins
2009-06-16 15:16 ` Michael S. Tsirkin
2009-06-16 14:55 ` Michael S. Tsirkin
2009-06-16 15:20 ` Gregory Haskins
2009-06-16 15:41 ` Michael S. Tsirkin
2009-06-16 16:17 ` Gregory Haskins
2009-06-16 16:19 ` Davide Libenzi
2009-06-16 17:01 ` Gregory Haskins
2009-06-17 16:38 ` Davide Libenzi
2009-06-17 17:28 ` Gregory Haskins
2009-06-17 17:44 ` Davide Libenzi
2009-06-17 19:17 ` Gregory Haskins
2009-06-17 19:50 ` Davide Libenzi
2009-06-17 21:48 ` Gregory Haskins
2009-06-17 23:21 ` Davide Libenzi
2009-06-18 6:23 ` Michael S. Tsirkin
2009-06-18 17:52 ` Davide Libenzi
2009-06-18 14:01 ` Gregory Haskins
2009-06-18 14:01 ` Gregory Haskins
2009-06-18 17:44 ` Davide Libenzi
2009-06-18 19:04 ` Gregory Haskins
2009-06-18 19:04 ` Gregory Haskins
2009-06-18 22:03 ` Davide Libenzi
2009-06-18 22:47 ` Gregory Haskins
2009-06-18 22:47 ` Gregory Haskins
2009-06-19 18:51 ` Gregory Haskins
2009-06-19 18:51 ` Gregory Haskins [this message]
2009-06-19 18:51 ` [PATCH 2/3] eventfd: add generalized " Gregory Haskins
2009-06-19 18:51 ` [PATCH 3/3] eventfd: add internal reference counting to fix notifier race conditions Gregory Haskins
2009-06-19 19:10 ` Davide Libenzi
2009-06-19 21:16 ` Gregory Haskins
2009-06-19 21:26 ` Davide Libenzi
2009-06-19 21:49 ` Gregory Haskins
2009-06-19 21:54 ` Davide Libenzi
2009-06-19 22:47 ` Davide Libenzi
2009-06-20 2:09 ` Gregory Haskins
2009-06-20 21:17 ` Davide Libenzi
2009-06-20 22:11 ` Davide Libenzi
2009-06-20 23:48 ` Davide Libenzi
2009-06-21 1:14 ` Gregory Haskins
2009-06-21 16:51 ` Davide Libenzi
2009-06-21 18:39 ` Gregory Haskins
2009-06-21 23:54 ` Davide Libenzi
2009-06-22 16:05 ` Gregory Haskins
2009-06-22 16:05 ` Gregory Haskins
2009-06-22 17:01 ` Davide Libenzi
2009-06-22 17:43 ` Gregory Haskins
2009-06-22 17:43 ` Gregory Haskins
2009-06-22 18:03 ` Davide Libenzi
2009-06-22 18:31 ` Gregory Haskins
2009-06-22 18:31 ` Gregory Haskins
2009-06-22 18:40 ` Davide Libenzi
2009-06-22 18:41 ` Michael S. Tsirkin
2009-06-22 18:51 ` Davide Libenzi
2009-06-22 19:05 ` Michael S. Tsirkin
2009-06-22 19:26 ` Gregory Haskins
2009-06-22 19:29 ` Davide Libenzi
2009-06-22 20:06 ` Gregory Haskins
2009-06-22 22:53 ` Davide Libenzi
2009-06-23 1:03 ` Gregory Haskins
2009-06-23 1:17 ` Davide Libenzi
2009-06-23 1:26 ` Gregory Haskins
2009-06-23 1:26 ` Gregory Haskins
2009-06-23 14:29 ` Davide Libenzi
2009-06-23 14:37 ` Gregory Haskins
2009-06-23 14:37 ` Gregory Haskins
2009-06-23 14:35 ` Davide Libenzi
2009-06-23 14:42 ` Gregory Haskins
2009-06-23 14:42 ` Gregory Haskins
2009-06-23 15:04 ` Michael S. Tsirkin
2009-06-22 20:28 ` Michael S. Tsirkin
2009-06-22 19:16 ` Gregory Haskins
2009-06-22 19:54 ` Davide Libenzi
2009-06-24 3:25 ` Rusty Russell
2009-06-24 22:45 ` Davide Libenzi
2009-06-25 11:42 ` Rusty Russell
2009-06-25 16:34 ` Davide Libenzi
2009-06-25 17:32 ` Gregory Haskins
2009-06-25 18:26 ` Michael S. Tsirkin
2009-06-25 18:41 ` Gregory Haskins
2009-06-26 11:23 ` Michael S. Tsirkin
2009-06-23 3:25 ` Rusty Russell
2009-06-23 14:31 ` Davide Libenzi
2009-06-25 0:19 ` Davide Libenzi
2009-06-21 1:05 ` Gregory Haskins
2009-06-16 17:54 ` [KVM-RFC PATCH 1/2] eventfd: add an explicit srcu based notifier interface Michael S. Tsirkin
2009-06-16 18:09 ` Gregory Haskins
2009-06-17 14:45 ` Michael S. Tsirkin
2009-06-17 15:02 ` Gregory Haskins
2009-06-17 16:25 ` Michael S. Tsirkin
2009-06-17 16:41 ` Gregory Haskins
2009-06-16 14:17 ` Gregory Haskins
2009-06-16 14:22 ` Gregory Haskins
2009-06-16 14:40 ` Gregory Haskins
2009-06-16 14:46 ` Michael S. Tsirkin
2009-06-18 9:03 ` Avi Kivity
2009-06-18 11:43 ` Gregory Haskins
2009-06-16 2:30 ` [KVM-RFC PATCH 2/2] eventfd: add module reference counting support for registered notifiers Gregory Haskins
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