X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=drivers%2Fchar%2Fhvc_vio.c;h=9add81ceb440506340de658ed574781991928118;hb=58a5b0a6346b71bf01f0d49cfcc91d3225a373aa;hp=f5212eb2b41d0d0436fe278817b5564dc49b7629;hpb=18ce920a6eba05c0d55cdc95fbbadf7e4c4b457b;p=powerpc.git

diff --git a/drivers/char/hvc_vio.c b/drivers/char/hvc_vio.c
index f5212eb2b4..9add81ceb4 100644
--- a/drivers/char/hvc_vio.c
+++ b/drivers/char/hvc_vio.c
@@ -31,10 +31,13 @@
 
 #include <linux/types.h>
 #include <linux/init.h>
+
 #include <asm/hvconsole.h>
 #include <asm/vio.h>
 #include <asm/prom.h>
 
+#include "hvc_console.h"
+
 char hvc_driver_name[] = "hvc_console";
 
 static struct vio_device_id hvc_driver_table[] __devinitdata = {
@@ -48,6 +51,14 @@ static int filtered_get_chars(uint32_t vtermno, char *buf, int count)
 	unsigned long got;
 	int i;
 
+	/*
+	 * Vio firmware will read up to SIZE_VIO_GET_CHARS at its own discretion
+	 * so we play safe and avoid the situation where got > count which could
+	 * overload the flip buffer.
+	 */
+	if (count < SIZE_VIO_GET_CHARS)
+		return -EAGAIN;
+
 	got = hvc_get_chars(vtermno, buf, count);
 
 	/*