When DBG() is used in a simple if-else, the resulting code path
currently depends on the definition of DBG(). Inserting the statement in
a "do { ... } while (0)" prevents this possible misuse.
Signed-off-by: Niels de Vos <ndevos@xxxxxxxxxx>
---
V2: add the missing closing }
Note, I have not found any offenders, but a mistake can easily be made.
The following example shows what can go wrong if little intention is
paid to the definition of the DBG() macro.
Example:
if something_went_wrong()
DBG("oh no, something went wrong!\n");
else
printk("all went fine\n");
Old result where the else is placed inside the first if-statment:
if something_went_wrong() {
if (omapfb_debug) {
printk(KERN_DEBUG "oh no, something went wrong!\n");
} else {
printk("all went fine\n");
}
}
New result where the else is an alternative to the first if-statement:
if something_went_wrong() {
do {
if (omapfb_debug)
printk(KERN_DEBUG "oh no, something went wrong!\n");
} while (0);
} else {
printk("all went fine\n");
}
---
drivers/video/omap2/omapfb/omapfb.h | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/video/omap2/omapfb/omapfb.h b/drivers/video/omap2/omapfb/omapfb.h
index 1305fc9..456c586 100644
--- a/drivers/video/omap2/omapfb/omapfb.h
+++ b/drivers/video/omap2/omapfb/omapfb.h
@@ -34,8 +34,10 @@
#ifdef DEBUG
extern unsigned int omapfb_debug;
#define DBG(format, ...) \
- if (omapfb_debug) \
- printk(KERN_DEBUG "OMAPFB: " format, ## __VA_ARGS__)
+ do { \
+ if (omapfb_debug) \
+ printk(KERN_DEBUG "OMAPFB: " format, ## __VA_ARGS__); \
+ } while (0)
#else
#define DBG(format, ...)
#endif
--
1.7.4.4
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