From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 23 Jun 2010 16:30:15 +0000 (+0200)
Subject: implement O_NONBLOCK for /proc/xen/xenbus
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6280f190da4dd083f14f704be6b3314311a7eacb;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

implement O_NONBLOCK for /proc/xen/xenbus

This patch implements O_NONBLOCK for /proc/xen/xenbus.  It is a simple
matter of returning -EAGAIN instead of waiting on a queue.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---

diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c
index a9592d981b10..9d5b519d2e4c 100644
--- a/drivers/xen/xenfs/xenbus.c
+++ b/drivers/xen/xenfs/xenbus.c
@@ -122,6 +122,9 @@ static ssize_t xenbus_file_read(struct file *filp,
 	mutex_lock(&u->reply_mutex);
 	while (list_empty(&u->read_buffers)) {
 		mutex_unlock(&u->reply_mutex);
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
 		ret = wait_event_interruptible(u->read_waitq,
 					       !list_empty(&u->read_buffers));
 		if (ret)