printk: rename vprintk_func to vprintk

The printk code is already hard enough to understand. Remove an
unnecessary indirection by renaming vprintk_func to vprintk (adding
the asmlinkage annotation), and removing the vprintk definition from
printk.c. That way, printk is implemented in terms of vprintk as one
would expect, and there's no "vprintk_func, what's that? Some function
pointer that gets set where?"

The declaration of vprintk in linux/printk.h already has the
__printf(1,0) attribute, there's no point repeating that with the
definition - it's for diagnostics in callers.

linux/printk.h already contains a static inline {return 0;} definition
of vprintk when !CONFIG_PRINTK.

Since the corresponding stub definition of vprintk_func was not marked
"static inline", any translation unit including internal.h would get a
definition of vprintk_func - it just so happens that for
!CONFIG_PRINTK, there is precisely one such TU, namely printk.c. Had
there been more, it would be a link error; now it's just a silly waste
of a few bytes of .text, which one must assume are rather precious to
anyone disabling PRINTK.

$ objdump -dr kernel/printk/printk.o
00000330 <vprintk_func>:
 330:   31 c0                   xor    %eax,%eax
 332:   c3                      ret
 333:   8d b4 26 00 00 00 00    lea    0x0(%esi,%eiz,1),%esi
 33a:   8d b6 00 00 00 00       lea    0x0(%esi),%esi

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210323144201.486050-1-linux@rasmusvillemoes.dk

diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index e7acc2888c8e164acb38ae486b8a4c8e164ed1b3..51615c909b2f3ffd585c619d37193b59fbb1317d 100644 (file)
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -19,7 +19,6 @@ int vprintk_store(int facility, int level,
 
 __printf(1, 0) int vprintk_default(const char *fmt, va_list args);
 __printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args);
 void __printk_safe_enter(void);
 void __printk_safe_exit(void);
 
@@ -54,8 +53,6 @@ void defer_console_output(void);
 
 #else
 
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; }
-
 /*
  * In !PRINTK builds we still export console_sem
  * semaphore and some of console functions (console_unlock()/etc.), so

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 2f829fbf0a1366c4f95e920a5c941caec74022a5..45ae60f3e489ab8b1db79766ed77b53dd77b93ba 100644 (file)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2180,12 +2180,6 @@ asmlinkage int vprintk_emit(int facility, int level,
 }
 EXPORT_SYMBOL(vprintk_emit);
 
-asmlinkage int vprintk(const char *fmt, va_list args)
-{
-       return vprintk_func(fmt, args);
-}
-EXPORT_SYMBOL(vprintk);
-
 int vprintk_default(const char *fmt, va_list args)
 {
        return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
@@ -2219,7 +2213,7 @@ asmlinkage __visible int printk(const char *fmt, ...)
        int r;
 
        va_start(args, fmt);
-       r = vprintk_func(fmt, args);
+       r = vprintk(fmt, args);
        va_end(args);
 
        return r;

diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index bbf5c1993636b7eafa20a9dee19042fd1c6444ed..7a1414622051a64356f0a4832a83e827d14613c6 100644 (file)
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -357,7 +357,7 @@ void __printk_safe_exit(void)
        this_cpu_dec(printk_context);
 }
 
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+asmlinkage int vprintk(const char *fmt, va_list args)
 {
 #ifdef CONFIG_KGDB_KDB
        /* Allow to pass printk() to kdb but avoid a recursion. */
@@ -411,3 +411,4 @@ void __init printk_safe_init(void)
        /* Flush pending messages that did not have scheduled IRQ works. */
        printk_safe_flush();
 }
+EXPORT_SYMBOL(vprintk);