From: Jeff Dike <jdike@addtoit.com>
Date: Thu, 15 Nov 2007 01:00:23 +0000 (-0800)
Subject: uml: fix spurious IRQ testing
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9ac625a3986034d79938baf9604210280fae35fa;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git

uml: fix spurious IRQ testing

The spurious IRQ testing in request_irq is mishandled in um_request_irq, which
sets the incoming file descriptors non-blocking only after request_irq
succeeds.  This results in the spurious irq calling read on a blocking
descriptor, and a hang.

Fixed by reversing the O_NONBLOCK setting and the request_irq call.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 70c2d625b07..ba11ccd6a8a 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -347,14 +347,15 @@ int um_request_irq(unsigned int irq, int fd, int type,
 {
 	int err;
 
-	err = request_irq(irq, handler, irqflags, devname, dev_id);
-	if (err)
-		return err;
-
-	if (fd != -1)
+	if (fd != -1) {
 		err = activate_fd(irq, fd, type, dev_id);
-	return err;
+		if (err)
+			return err;
+	}
+
+	return request_irq(irq, handler, irqflags, devname, dev_id);
 }
+
 EXPORT_SYMBOL(um_request_irq);
 EXPORT_SYMBOL(reactivate_fd);