printk - fix compilation for CONFIG_PRINTK=n

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/mem.c

@@ -825,7 +825,9 @@ static const struct memdev {
 	 [7] = { "full", 0666, &full_fops, NULL },
 	 [8] = { "random", 0666, &random_fops, NULL },
 	 [9] = { "urandom", 0666, &urandom_fops, NULL },
+#ifdef CONFIG_PRINTK
 	[11] = { "kmsg", 0644, &kmsg_fops, NULL },
+#endif
 #ifdef CONFIG_CRASH_DUMP
 	[12] = { "oldmem", 0, &oldmem_fops, NULL },
 #endif

kernel/printk.c

@@ -126,7 +126,6 @@ EXPORT_SYMBOL(console_set_on_cmdline);
 /* Flag: console code may call schedule() */
 static int console_may_schedule;
 
-#ifdef CONFIG_PRINTK
 /*
  * The printk log buffer consists of a chain of concatenated variable
  * length records. Every record starts with a record header, containing
@@ -208,16 +207,9 @@ struct log {
  */
 static DEFINE_RAW_SPINLOCK(logbuf_lock);
 
-/* cpu currently holding logbuf_lock */
-static volatile unsigned int logbuf_cpu = UINT_MAX;
-
-#define LOG_LINE_MAX 1024
-
-/* record buffer */
-#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
-static char __log_buf[__LOG_BUF_LEN];
-static char *log_buf = __log_buf;
-static u32 log_buf_len = __LOG_BUF_LEN;
+/* the next printk record to read by syslog(READ) or /proc/kmsg */
+static u64 syslog_seq;
+static u32 syslog_idx;
 
 /* index and sequence number of the first record stored in the buffer */
 static u64 log_first_seq;
@@ -225,15 +217,23 @@ static u32 log_first_idx;
 
 /* index and sequence number of the next record to store in the buffer */
 static u64 log_next_seq;
+#ifdef CONFIG_PRINTK
 static u32 log_next_idx;
 
 /* the next printk record to read after the last 'clear' command */
 static u64 clear_seq;
 static u32 clear_idx;
 
-/* the next printk record to read by syslog(READ) or /proc/kmsg */
-static u64 syslog_seq;
-static u32 syslog_idx;
+#define LOG_LINE_MAX 1024
+
+/* record buffer */
+#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
+static char __log_buf[__LOG_BUF_LEN];
+static char *log_buf = __log_buf;
+static u32 log_buf_len = __LOG_BUF_LEN;
+
+/* cpu currently holding logbuf_lock */
+static volatile unsigned int logbuf_cpu = UINT_MAX;
 
 /* human readable text of the record */
 static char *log_text(const struct log *msg)
@@ -1425,13 +1425,16 @@ asmlinkage int printk(const char *fmt, ...)
 	return r;
 }
 EXPORT_SYMBOL(printk);
+
 #else
 
-static void call_console_drivers(int level, const char *text, size_t len)
-{
-}
+#define LOG_LINE_MAX 0
+static struct log *log_from_idx(u32 idx) { return NULL; }
+static u32 log_next(u32 idx) { return 0; }
+static char *log_text(const struct log *msg) { return NULL; }
+static void call_console_drivers(int level, const char *text, size_t len) {}
 
-#endif
+#endif /* CONFIG_PRINTK */
 
 static int __add_preferred_console(char *name, int idx, char *options,
 				   char *brl_options)
@@ -1715,7 +1718,7 @@ static u32 console_idx;
  * by printk().  If this is the case, console_unlock(); emits
  * the output prior to releasing the lock.
  *
- * If there is output waiting, we wake it /dev/kmsg and syslog() users.
+ * If there is output waiting, we wake /dev/kmsg and syslog() users.
  *
  * console_unlock(); may be called from any context.
  */