[take25 6/6] kevent: Pipe notifications.

Evgeniy Polyakov
2006-11-21T16:30:45Z

Pipe notifications.

diff --git a/fs/pipe.c b/fs/pipe.c
index f3b6f71..aeaee9c 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -16,6 +16,7 @@
#include <linux/uio.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
+#include <linux/kevent.h>

#include <asm/uaccess.h>
#include <asm/ioctls.h>
@@ -312,6 +313,7 @@ redo:
break;
}
if (do_wakeup) {
+ kevent_pipe_notify(inode, KEVENT_SOCKET_SEND);
wake_up_interruptible_sync(&pipe->wait);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
@@ -321,6 +323,7 @@ redo:

/* Signal writers asynchronously that there is more room. */
if (do_wakeup) {
+ kevent_pipe_notify(inode, KEVENT_SOCKET_SEND);
wake_up_interruptible(&pipe->wait);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
@@ -490,6 +493,7 @@ redo2:
break;
}
if (do_wakeup) {
+ kevent_pipe_notify(inode, KEVENT_SOCKET_RECV);
wake_up_interruptible_sync(&pipe->wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
do_wakeup = 0;
@@ -501,6 +505,7 @@ redo2:
out:
mutex_unlock(&inode->i_mutex);
if (do_wakeup) {
+ kevent_pipe_notify(inode, KEVENT_SOCKET_RECV);
wake_up_interruptible(&pipe->wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
}
@@ -605,6 +610,7 @@ pipe_release(struct inode *inode, int de
free_pipe_info(inode);
} else {
wake_up_interruptible(&pipe->wait);
+ kevent_pipe_notify(inode, KEVENT_SOCKET_SEND|KEVENT_SOCKET_RECV);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
diff --git a/kernel/kevent/kevent_pipe.c b/kernel/kevent/kevent_pipe.c
new file mode 100644
index 0000000..5080642
--- /dev/null
+++ b/kernel/kevent/kevent_pipe.c
@@ -0,0 +1,117 @@
+/*
+ * kevent_pipe.c
+ *
+ * 2006 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/kevent.h>
+#include <linux/pipe_fs_i.h>
+
+static int kevent_pipe_callback(struct kevent *k)
+{
+ struct inode *inode = k->st->origin;
+ struct pipe_inode_info *pipe = inode->i_pipe;
+ int nrbufs = pipe->nrbufs;
+
+ if (k->event.event & KEVENT_SOCKET_RECV && nrbufs > 0) {
+ if (!pipe->writers)
+ return -1;
+ return 1;
+ }
+
+ if (k->event.event & KEVENT_SOCKET_SEND && nrbufs < PIPE_BUFFERS) {
+ if (!pipe->readers)
+ return -1;
+ return 1;
+ }
+
+ return 0;
+}
+
+int kevent_pipe_enqueue(struct kevent *k)
+{
+ struct file *pipe;
+ int err = -EBADF;
+ struct inode *inode;
+
+ pipe = fget(k->event.id.raw[0]);
+ if (!pipe)
+ goto err_out_exit;
+
+ inode = igrab(pipe->f_dentry->d_inode);
+ if (!inode)
+ goto err_out_fput;
+
+ err = kevent_storage_enqueue(&inode->st, k);
+ if (err)
+ goto err_out_iput;
+
+ if (k->event.req_flags & KEVENT_REQ_ALWAYS_QUEUE) {
+ kevent_requeue(k);
+ err = 0;
+ } else {
+ err = k->callbacks.callback(k);
+ if (err)
+ goto err_out_dequeue;
+ }
+
+ fput(pipe);
+
+ return err;
+
+err_out_dequeue:
+ kevent_storage_dequeue(k->st, k);
+err_out_iput:
+ iput(inode);
+err_out_fput:
+ fput(pipe);
+err_out_exit:
+ return err;
+}
+
+int kevent_pipe_dequeue(struct kevent *k)
+{
+ struct inode *inode = k->st->origin;
+
+ kevent_storage_dequeue(k->st, k);
+ iput(inode);
+
+ return 0;
+}
+
+void kevent_pipe_notify(struct inode *inode, u32 event)
+{
+ kevent_storage_ready(&inode->st, NULL, event);
+}
+
+static int __init kevent_init_pipe(void)
+{
+ struct kevent_callbacks sc = {
+ .callback = &kevent_pipe_callback,
+ .enqueue = &kevent_pipe_enqueue,
+ .dequeue = &kevent_pipe_dequeue};
+
+ return kevent_add_callbacks(&sc, KEVENT_PIPE);
+}
+module_init(kevent_init_pipe);