drivers/rtc: correct error-handling code

This code is not executed before ds1307->rtc has been successfully
initialized to the result of calling rtc_device_register.  Thus the test
that ds1307->rtc is not NULL is always true.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@match exists@
expression x, E;
statement S1, S2;
@@

x = rtc_device_register(...)
... when != x = E
(
*  if (x == NULL || ...) S1 else S2
|
*  if (x == NULL && ...) S1 else S2
)
// </smpl>

Signed-off-by: Julia Lawall <[email protected]>
Acked-by: Wolfram Sang <[email protected]>
Cc: David Brownell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 47a93c022d91b20bc840bd8158bb1097514eaa7b..eb99ee4fa0f5778a39e4faddd892766b06d0f078 100644 (file)
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -896,8 +896,7 @@ read_rtc:
        return 0;
 
 exit_irq:
-       if (ds1307->rtc)
-               rtc_device_unregister(ds1307->rtc);
+       rtc_device_unregister(ds1307->rtc);
 exit_free:
        kfree(ds1307);
        return err;