Commit 6b916706 authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

printk: inline log_output(),log_store() in vprintk_store() 



In preparation for removing logbuf_lock, inline log_output()
and log_store() into vprintk_store(). This will simplify dealing
with the various code branches and fallbacks that are possible.

Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20201209004453.17720-2-john.ogness@linutronix.de
parent 43d6ecd9

kernel/printk/printk.c

+67 −78
Original line number Diff line number Diff line
@@ -491,52 +491,6 @@ static void truncate_msg(u16 *text_len, u16 *trunc_msg_len) 
		*trunc_msg_len = 0;

}



/* insert record into the buffer, discard old ones, update heads */

static int log_store(u32 caller_id, int facility, int level,

		     enum log_flags flags, u64 ts_nsec,

		     const struct dev_printk_info *dev_info,

		     const char *text, u16 text_len)

{

	struct prb_reserved_entry e;

	struct printk_record r;

	u16 trunc_msg_len = 0;



	prb_rec_init_wr(&r, text_len);



	if (!prb_reserve(&e, prb, &r)) {

		/* truncate the message if it is too long for empty buffer */

		truncate_msg(&text_len, &trunc_msg_len);

		prb_rec_init_wr(&r, text_len + trunc_msg_len);

		/* survive when the log buffer is too small for trunc_msg */

		if (!prb_reserve(&e, prb, &r))

			return 0;

	}



	/* fill message */

	memcpy(&r.text_buf[0], text, text_len);

	if (trunc_msg_len)

		memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);

	r.info->text_len = text_len + trunc_msg_len;

	r.info->facility = facility;

	r.info->level = level & 7;

	r.info->flags = flags & 0x1f;

	if (ts_nsec > 0)

		r.info->ts_nsec = ts_nsec;

	else

		r.info->ts_nsec = local_clock();

	r.info->caller_id = caller_id;

	if (dev_info)

		memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));



	/* A message without a trailing newline can be continued. */

	if (!(flags & LOG_NEWLINE))

		prb_commit(&e);

	else

		prb_final_commit(&e);



	return (text_len + trunc_msg_len);

}



int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);



static int syslog_action_restricted(int type)
@@ -1907,44 +1861,28 @@ static inline u32 printk_caller_id(void) 
		0x80000000 + raw_smp_processor_id();

}



static size_t log_output(int facility, int level, enum log_flags lflags,

			 const struct dev_printk_info *dev_info,

			 char *text, size_t text_len)

{

	const u32 caller_id = printk_caller_id();



	if (lflags & LOG_CONT) {

		struct prb_reserved_entry e;

		struct printk_record r;



		prb_rec_init_wr(&r, text_len);

		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {

			memcpy(&r.text_buf[r.info->text_len], text, text_len);

			r.info->text_len += text_len;

			if (lflags & LOG_NEWLINE) {

				r.info->flags |= LOG_NEWLINE;

				prb_final_commit(&e);

			} else {

				prb_commit(&e);

			}

			return text_len;

		}

	}



	/* Store it in the record log */

	return log_store(caller_id, facility, level, lflags, 0,

			 dev_info, text, text_len);

}



/* Must be called under logbuf_lock. */

int vprintk_store(int facility, int level,

		  const struct dev_printk_info *dev_info,

		  const char *fmt, va_list args)

{

	const u32 caller_id = printk_caller_id();

	static char textbuf[LOG_LINE_MAX];

	char *text = textbuf;

	size_t text_len;

	struct prb_reserved_entry e;

	enum log_flags lflags = 0;

	struct printk_record r;

	u16 trunc_msg_len = 0;

	char *text = textbuf;

	u16 text_len;

	u64 ts_nsec;



	/*

	 * Since the duration of printk() can vary depending on the message

	 * and state of the ringbuffer, grab the timestamp now so that it is

	 * close to the call of printk(). This provides a more deterministic

	 * timestamp with respect to the caller.

	 */

	ts_nsec = local_clock();



	/*

	 * The printf needs to come first; we need the syslog
@@ -1983,7 +1921,58 @@ int vprintk_store(int facility, int level, 
	if (dev_info)

		lflags |= LOG_NEWLINE;



	return log_output(facility, level, lflags, dev_info, text, text_len);

	if (lflags & LOG_CONT) {

		prb_rec_init_wr(&r, text_len);

		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {

			memcpy(&r.text_buf[r.info->text_len], text, text_len);

			r.info->text_len += text_len;



			if (lflags & LOG_NEWLINE) {

				r.info->flags |= LOG_NEWLINE;

				prb_final_commit(&e);

			} else {

				prb_commit(&e);

			}



			return text_len;

		}

	}



	/*

	 * Explicitly initialize the record before every prb_reserve() call.

	 * prb_reserve_in_last() and prb_reserve() purposely invalidate the

	 * structure when they fail.

	 */

	prb_rec_init_wr(&r, text_len);

	if (!prb_reserve(&e, prb, &r)) {

		/* truncate the message if it is too long for empty buffer */

		truncate_msg(&text_len, &trunc_msg_len);



		prb_rec_init_wr(&r, text_len + trunc_msg_len);

		if (!prb_reserve(&e, prb, &r))

			return 0;

	}



	/* fill message */

	memcpy(&r.text_buf[0], text, text_len);

	if (trunc_msg_len)

		memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);

	r.info->text_len = text_len + trunc_msg_len;

	r.info->facility = facility;

	r.info->level = level & 7;

	r.info->flags = lflags & 0x1f;

	r.info->ts_nsec = ts_nsec;

	r.info->caller_id = caller_id;

	if (dev_info)

		memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));



	/* A message without a trailing newline can be continued. */

	if (!(lflags & LOG_NEWLINE))

		prb_commit(&e);

	else

		prb_final_commit(&e);



	return (text_len + trunc_msg_len);

}



asmlinkage int vprintk_emit(int facility, int level,