[PATCH v2 0/4] printk: some minor fixups

[PATCH v2 0/4] printk: some minor fixups

[Alex Elder]

This series makes some minor changes to kernel/printk/printk.c.
I've been poking around that file and will have a few more
substantive changes to propose soon, but I've been carrying
around these little things for a bit and thought I should
just get them out there.

					-Alex

History:
v2: - Renamed CONFIG_MESSAGE_LOGLEVEL_DEFAULT, as suggested
    - Added Reviewed-by (etc.) annotations

This series, based on v3.16-rc4, is available here:
    http://git.linaro.org/landing-teams/working/broadcom/kernel.git
    Branch review/minor-printk-fixes-v2

Alex Elder (4):
  printk: rename DEFAULT_MESSAGE_LOGLEVEL
  printk: fix some comments
  printk: use a clever macro
  printk: miscellaneous cleanups

 include/linux/printk.h |  2 +-
 kernel/printk/printk.c | 63 ++++++++++++++++++++++----------------------------
 lib/Kconfig.debug      |  2 +-
 3 files changed, 30 insertions(+), 37 deletions(-)

-- 
1.9.1

[PATCH v2 1/4] printk: rename DEFAULT_MESSAGE_LOGLEVEL

[Alex Elder]

This commit:
    a8fe19eb kernel/printk: use symbolic defines for console loglevels
makes consistent use of symbolic values for printk() log levels.

The naming scheme used is different from the one used for
DEFAULT_MESSAGE_LOGLEVEL though.  Change that symbol name to be
MESSAGE_LOGLEVEL_DEFAULT for consistency.  And because the value
of that symbol comes from a similarly-named config option, rename
CONFIG_DEFAULT_MESSAGE_LOGLEVEL as well.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 include/linux/printk.h | 2 +-
 kernel/printk/printk.c | 2 +-
 lib/Kconfig.debug      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 319ff7e..0990997 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -31,7 +31,7 @@ static inline const char *printk_skip_level(const char *buffer)
 }
 
 /* printk's without a loglevel use this.. */
-#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
+#define MESSAGE_LOGLEVEL_DEFAULT CONFIG_MESSAGE_LOGLEVEL_DEFAULT
 
 /* We show everything that is MORE important than this.. */
 #define CONSOLE_LOGLEVEL_SILENT  0 /* Mum's the word */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 13e839d..ac2b64e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -56,7 +56,7 @@
 
 int console_printk[4] = {
 	CONSOLE_LOGLEVEL_DEFAULT,	/* console_loglevel */
-	DEFAULT_MESSAGE_LOGLEVEL,	/* default_message_loglevel */
+	MESSAGE_LOGLEVEL_DEFAULT,	/* default_message_loglevel */
 	CONSOLE_LOGLEVEL_MIN,		/* minimum_console_loglevel */
 	CONSOLE_LOGLEVEL_DEFAULT,	/* default_console_loglevel */
 };
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7a638aa..fd939e1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -15,7 +15,7 @@ config PRINTK_TIME
 	  The behavior is also controlled by the kernel command line
 	  parameter printk.time=1. See Documentation/kernel-parameters.txt
 
-config DEFAULT_MESSAGE_LOGLEVEL
+config MESSAGE_LOGLEVEL_DEFAULT
 	int "Default message log level (1-7)"
 	range 1 7
 	default "4"
-- 
1.9.1

[PATCH v2 2/4] printk: fix some comments

[Alex Elder]

This patch fixes a few comments that don't accurately describe their
corresponding code.  It also fixes some minor typographical errors.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
---
 kernel/printk/printk.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ac2b64e..646146c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -113,9 +113,9 @@ static int __down_trylock_console_sem(unsigned long ip)
  * This is used for debugging the mess that is the VT code by
  * keeping track if we have the console semaphore held. It's
  * definitely not the perfect debug tool (we don't know if _WE_
- * hold it are racing, but it helps tracking those weird code
- * path in the console code where we end up in places I want
- * locked without the console sempahore held
+ * hold it and are racing, but it helps tracking those weird code
+ * paths in the console code where we end up in places I want
+ * locked without the console sempahore held).
  */
 static int console_locked, console_suspended;
 
@@ -146,8 +146,8 @@ static int console_may_schedule;
  * the overall length of the record.
  *
  * The heads to the first and last entry in the buffer, as well as the
- * sequence numbers of these both entries are maintained when messages
- * are stored..
+ * sequence numbers of these entries are maintained when messages are
+ * stored.
  *
  * If the heads indicate available messages, the length in the header
  * tells the start next message. A length == 0 for the next message
@@ -344,7 +344,7 @@ static int log_make_free_space(u32 msg_size)
 	while (log_first_seq < log_next_seq) {
 		if (logbuf_has_space(msg_size, false))
 			return 0;
-		/* drop old messages until we have enough continuous space */
+		/* drop old messages until we have enough contiguous space */
 		log_first_idx = log_next(log_first_idx);
 		log_first_seq++;
 	}
@@ -1476,7 +1476,7 @@ static struct cont {
 	struct task_struct *owner;	/* task of first print*/
 	u64 ts_nsec;			/* time of first print */
 	u8 level;			/* log level of first message */
-	u8 facility;			/* log level of first message */
+	u8 facility;			/* log facility of first message */
 	enum log_flags flags;		/* prefix, newline flags */
 	bool flushed:1;			/* buffer sealed and committed */
 } cont;
@@ -1881,11 +1881,12 @@ static int __add_preferred_console(char *name, int idx, char *options,
 	return 0;
 }
 /*
- * Set up a list of consoles.  Called from init/main.c
+ * Set up a console.  Called via do_early_param() in init/main.c
+ * for each "console=" parameter in the boot command line.
  */
 static int __init console_setup(char *str)
 {
-	char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
+	char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */
 	char *s, *options, *brl_options = NULL;
 	int idx;
 
@@ -2045,8 +2046,8 @@ EXPORT_SYMBOL(console_lock);
 /**
  * console_trylock - try to lock the console system for exclusive use.
  *
- * Tried to acquire a lock which guarantees that the caller has
- * exclusive access to the console system and the console_drivers list.
+ * Try to acquire a lock which guarantees that the caller has exclusive
+ * access to the console system and the console_drivers list.
  *
  * returns 1 on success, and 0 on failure to acquire the lock.
  */
-- 
1.9.1

[PATCH v2 3/4] printk: use a clever macro

[Alex Elder]

Use the IS_ENABLED() macro rather than #ifdef blocks to set certain
global values.

Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
---
 kernel/printk/printk.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 646146c..6f75e8a 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -453,11 +453,7 @@ static int log_store(int facility, int level,
 	return msg->text_len;
 }
 
-#ifdef CONFIG_SECURITY_DMESG_RESTRICT
-int dmesg_restrict = 1;
-#else
-int dmesg_restrict;
-#endif
+int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
 
 static int syslog_action_restricted(int type)
 {
@@ -947,11 +943,7 @@ static inline void boot_delay_msec(int level)
 }
 #endif
 
-#if defined(CONFIG_PRINTK_TIME)
-static bool printk_time = 1;
-#else
-static bool printk_time;
-#endif
+static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
 
 static size_t print_time(u64 ts, char *buf)
-- 
1.9.1

[PATCH v2 4/4] printk: miscellaneous cleanups

[Alex Elder]

This patch contains some small cleanups to kernel/printk/printk.c.
None of them should cause any change in behavior.
  - When CONFIG_PRINTK is defined, parenthesize the value of LOG_LINE_MAX.
  - When CONFIG_PRINTK is *not* defined, there is an extra LOG_LINE_MAX
    definition; delete it.
  - Pull an assignment out of a conditional expression in console_setup().
  - Use isdigit() in console_setup() rather than open coding it.
  - In update_console_cmdline(), drop a NUL-termination assignment;
    the strlcpy() call that precedes it guarantees it's not needed.
  - Simplify some logic in printk_timed_ratelimit().

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
---
 kernel/printk/printk.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 6f75e8a..909029e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -45,6 +45,7 @@
 #include <linux/poll.h>
 #include <linux/irq_work.h>
 #include <linux/utsname.h>
+#include <linux/ctype.h>
 
 #include <asm/uaccess.h>
 
@@ -257,7 +258,7 @@ static u64 clear_seq;
 static u32 clear_idx;
 
 #define PREFIX_MAX		32
-#define LOG_LINE_MAX		1024 - PREFIX_MAX
+#define LOG_LINE_MAX		(1024 - PREFIX_MAX)
 
 /* record buffer */
 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
@@ -1794,7 +1795,7 @@ EXPORT_SYMBOL(printk);
 
 #define LOG_LINE_MAX		0
 #define PREFIX_MAX		0
-#define LOG_LINE_MAX 0
+
 static u64 syslog_seq;
 static u32 syslog_idx;
 static u64 console_seq;
@@ -1895,7 +1896,8 @@ static int __init console_setup(char *str)
 		strncpy(buf, str, sizeof(buf) - 1);
 	}
 	buf[sizeof(buf) - 1] = 0;
-	if ((options = strchr(str, ',')) != NULL)
+	options = strchr(str, ',');
+	if (options)
 		*(options++) = 0;
 #ifdef __sparc__
 	if (!strcmp(str, "ttya"))
@@ -1904,7 +1906,7 @@ static int __init console_setup(char *str)
 		strcpy(buf, "ttyS1");
 #endif
 	for (s = buf; *s; s++)
-		if ((*s >= '0' && *s <= '9') || *s == ',')
+		if (isdigit(*s) || *s == ',')
 			break;
 	idx = simple_strtoul(s, NULL, 10);
 	*s = 0;
@@ -1943,7 +1945,6 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha
 	     i++, c++)
 		if (strcmp(c->name, name) == 0 && c->index == idx) {
 			strlcpy(c->name, name_new, sizeof(c->name));
-			c->name[sizeof(c->name) - 1] = 0;
 			c->options = options;
 			c->index = idx_new;
 			return i;
@@ -2611,14 +2612,13 @@ EXPORT_SYMBOL(__printk_ratelimit);
 bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 			unsigned int interval_msecs)
 {
-	if (*caller_jiffies == 0
-			|| !time_in_range(jiffies, *caller_jiffies,
-					*caller_jiffies
-					+ msecs_to_jiffies(interval_msecs))) {
-		*caller_jiffies = jiffies;
-		return true;
-	}
-	return false;
+	unsigned long elapsed = jiffies - *caller_jiffies;
+
+	if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs))
+		return false;
+
+	*caller_jiffies = jiffies;
+	return true;
 }
 EXPORT_SYMBOL(printk_timed_ratelimit);
 
-- 
1.9.1