ALSA: core - strip too long file names in snd_print*()

When modules are built with M= option, they pass long file paths to
__FILE__.  This results in ugly outputs of snd_print*() when
CONFIG_SND_VERBOSE_PRINTK is set.

This patch adds a check of the path and strips the leading path dirs
if the file name is an absolute path to improve the readability of logs.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/misc.c b/sound/core/misc.c
index a9710e0..1d29e67 100644
--- a/sound/core/misc.c
+++ b/sound/core/misc.c
@@ -35,8 +35,17 @@
 EXPORT_SYMBOL(release_and_free_resource);
 
 #ifdef CONFIG_SND_VERBOSE_PRINTK
-void snd_verbose_printk(const char *file, int line, const char *format, ...)
+static const char *sanity_file_name(const char *path)
 {
+	if (*path == '/')
+		return strrchr(path, '/') + 1;
+	else
+		return path;
+}
+
+void snd_verbose_printk(const char *path, int line, const char *format, ...)
+{
+	const char *file = sanity_file_name(path);
 	va_list args;
 	
 	if (format[0] == '<' && format[1] >= '0' && format[1] <= '7' && format[2] == '>') {
@@ -56,8 +65,9 @@
 #endif
 
 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_VERBOSE_PRINTK)
-void snd_verbose_printd(const char *file, int line, const char *format, ...)
+void snd_verbose_printd(const char *path, int line, const char *format, ...)
 {
+	const char *file = sanity_file_name(path);
 	va_list args;
 	
 	if (format[0] == '<' && format[1] >= '0' && format[1] <= '7' && format[2] == '>') {