ALSA: Introduce snd_BUG_ON() macro
Introduced snd_BUG_ON() macro as a replacement of snd_assert() macro.
snd_assert() is pretty ugly as it has the control flow in its argument.
OTOH, snd_BUG_ON() behaves like a normal conditional, thus it's much
easier to read the flow.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
index e13c4e6..df699e4 100644
--- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
+++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
@@ -6173,6 +6173,47 @@
When no debug flag is set, this macro is ignored.
</para>
</section>
+
+ <section id="useful-functions-snd-bug-on">
+ <title><function>snd_BUG_ON()</function></title>
+ <para>
+ <function>snd_BUG_ON()</function> macro is similar with
+ <function>WARN_ON()</function> macro. For example,
+
+ <informalexample>
+ <programlisting>
+<![CDATA[
+ snd_BUG_ON(!pointer);
+]]>
+ </programlisting>
+ </informalexample>
+
+ or it can be used as the condition,
+ <informalexample>
+ <programlisting>
+<![CDATA[
+ if (snd_BUG_ON(non_zero_is_bug))
+ return -EINVAL;
+]]>
+ </programlisting>
+ </informalexample>
+
+ </para>
+
+ <para>
+ The macro takes an conditional expression to evaluate.
+ When <constant>CONFIG_SND_DEBUG</constant>, is set, the
+ expression is actually evaluated. If it's non-zero, it shows
+ the warning message such as
+ <computeroutput>BUG? (xxx)</computeroutput>
+ normally followed by stack trace. It returns the evaluated
+ value.
+ When no <constant>CONFIG_SND_DEBUG</constant> is set, this
+ macro always returns zero.
+ </para>
+
+ </section>
+
</chapter>
diff --git a/include/sound/core.h b/include/sound/core.h
index 1a4ff0b..938c36a 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -28,6 +28,7 @@
#include <linux/rwsem.h> /* struct rw_semaphore */
#include <linux/pm.h> /* pm_message_t */
#include <linux/device.h>
+#include <linux/stringify.h>
/* number of supported soundcards */
#ifdef CONFIG_SND_DYNAMIC_MINORS
@@ -405,11 +406,14 @@
dump_stack(); \
} while (0)
+#define snd_BUG_ON(cond) WARN((cond), "BUG? (%s)\n", __stringify(cond))
+
#else /* !CONFIG_SND_DEBUG */
#define snd_printd(fmt, args...) /* nothing */
#define snd_assert(expr, args...) (void)(expr)
#define snd_BUG() /* nothing */
+#define snd_BUG_ON(cond) ({/*(void)(cond);*/ 0;}) /* always false */
#endif /* CONFIG_SND_DEBUG */