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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2018-12-11 10:49:05 +0100
committerPetr Mladek <pmladek@suse.com>2018-12-12 11:21:14 +0100
commit07c17732bd687567802aaa5fa5c101c2776565d1 (patch)
tree275be05af0872ec5ab06592d9a3a12ddd0868b90 /kernel/printk/printk.c
parentprintk: fix printk_time race. (diff)
downloadlinux-07c17732bd687567802aaa5fa5c101c2776565d1.tar.xz
linux-07c17732bd687567802aaa5fa5c101c2776565d1.zip
printk: Remove print_prefix() calls with NULL buffer.
We can save lines/size by removing print_prefix() with buf == NULL. This patch makes no functional change. Link: http://lkml.kernel.org/r/1544521745-11925-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp To: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel/printk/printk.c')
-rw-r--r--kernel/printk/printk.c39
1 files changed, 14 insertions, 25 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c7d217764db3..91db332ccf4d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1228,13 +1228,15 @@ static inline void boot_delay_msec(int level)
static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+static size_t print_syslog(unsigned int level, char *buf)
+{
+ return sprintf(buf, "<%u>", level);
+}
+
static size_t print_time(u64 ts, char *buf)
{
unsigned long rem_nsec = do_div(ts, 1000000000);
- if (!buf)
- return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
-
return sprintf(buf, "[%5lu.%06lu] ",
(unsigned long)ts, rem_nsec / 1000);
}
@@ -1243,24 +1245,11 @@ static size_t print_prefix(const struct printk_log *msg, bool syslog,
bool time, char *buf)
{
size_t len = 0;
- unsigned int prefix = (msg->facility << 3) | msg->level;
-
- if (syslog) {
- if (buf) {
- len += sprintf(buf, "<%u>", prefix);
- } else {
- len += 3;
- if (prefix > 999)
- len += 3;
- else if (prefix > 99)
- len += 2;
- else if (prefix > 9)
- len++;
- }
- }
+ if (syslog)
+ len = print_syslog((msg->facility << 3) | msg->level, buf);
if (time)
- len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
+ len += print_time(msg->ts_nsec, buf + len);
return len;
}
@@ -1270,6 +1259,8 @@ static size_t msg_print_text(const struct printk_log *msg, bool syslog,
const char *text = log_text(msg);
size_t text_size = msg->text_len;
size_t len = 0;
+ char prefix[PREFIX_MAX];
+ const size_t prefix_len = print_prefix(msg, syslog, time, prefix);
do {
const char *next = memchr(text, '\n', text_size);
@@ -1284,19 +1275,17 @@ static size_t msg_print_text(const struct printk_log *msg, bool syslog,
}
if (buf) {
- if (print_prefix(msg, syslog, time, NULL) +
- text_len + 1 >= size - len)
+ if (prefix_len + text_len + 1 >= size - len)
break;
- len += print_prefix(msg, syslog, time, buf + len);
+ memcpy(buf + len, prefix, prefix_len);
+ len += prefix_len;
memcpy(buf + len, text, text_len);
len += text_len;
buf[len++] = '\n';
} else {
/* SYSLOG_ACTION_* buffer size only calculation */
- len += print_prefix(msg, syslog, time, NULL);
- len += text_len;
- len++;
+ len += prefix_len + text_len + 1;
}
text = next;