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Commit 077a1cc0 authored by Nikitas Angelinas's avatar Nikitas Angelinas Committed by Petr Mladek
Browse files

printk: Clean up do_syslog() error handling 

The error variable in do_syslog() is preemptively set to the error code
before the error condition is checked, and then set to 0 if the error
condition is not encountered. This is not necessary, as it is likely
simpler to return immediately upon encountering the error condition. A
redundant set of the error variable to 0 is also removed.

This patch has been build-tested on x86_64, but not tested for
functionality.

Link: http://lkml.kernel.org/r/20170730033636.GA935@vostro


Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarNikitas Angelinas <nikitas.angelinas@gmail.com>
Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent 5a814231

kernel/printk/printk.c

+12 −23
Original line number Diff line number Diff line
@@ -1435,7 +1435,7 @@ int do_syslog(int type, char __user *buf, int len, int source) 


	error = check_syslog_permissions(type, source);

	if (error)

		goto out;

		return error;



	switch (type) {

	case SYSLOG_ACTION_CLOSE:	/* Close log */
@@ -1443,20 +1443,16 @@ int do_syslog(int type, char __user *buf, int len, int source) 
	case SYSLOG_ACTION_OPEN:	/* Open log */

		break;

	case SYSLOG_ACTION_READ:	/* Read from log */

		error = -EINVAL;

		if (!buf || len < 0)

			goto out;

		error = 0;

			return -EINVAL;

		if (!len)

			goto out;

		if (!access_ok(VERIFY_WRITE, buf, len)) {

			error = -EFAULT;

			goto out;

		}

			return 0;

		if (!access_ok(VERIFY_WRITE, buf, len))

			return -EFAULT;

		error = wait_event_interruptible(log_wait,

						 syslog_seq != log_next_seq);

		if (error)

			goto out;

			return error;

		error = syslog_print(buf, len);

		break;

	/* Read/clear last kernel messages */
@@ -1465,16 +1461,12 @@ int do_syslog(int type, char __user *buf, int len, int source) 
		/* FALL THRU */

	/* Read last kernel messages */

	case SYSLOG_ACTION_READ_ALL:

		error = -EINVAL;

		if (!buf || len < 0)

			goto out;

		error = 0;

			return -EINVAL;

		if (!len)

			goto out;

		if (!access_ok(VERIFY_WRITE, buf, len)) {

			error = -EFAULT;

			goto out;

		}

			return 0;

		if (!access_ok(VERIFY_WRITE, buf, len))

			return -EFAULT;

		error = syslog_print_all(buf, len, clear);

		break;

	/* Clear ring buffer */
@@ -1496,15 +1488,13 @@ int do_syslog(int type, char __user *buf, int len, int source) 
		break;

	/* Set level of messages printed to console */

	case SYSLOG_ACTION_CONSOLE_LEVEL:

		error = -EINVAL;

		if (len < 1 || len > 8)

			goto out;

			return -EINVAL;

		if (len < minimum_console_loglevel)

			len = minimum_console_loglevel;

		console_loglevel = len;

		/* Implicitly re-enable logging to console */

		saved_console_loglevel = LOGLEVEL_DEFAULT;

		error = 0;

		break;

	/* Number of chars in the log buffer */

	case SYSLOG_ACTION_SIZE_UNREAD:
@@ -1526,7 +1516,6 @@ int do_syslog(int type, char __user *buf, int len, int source) 
			u64 seq = syslog_seq;

			u32 idx = syslog_idx;



			error = 0;

			while (seq < log_next_seq) {

				struct printk_log *msg = log_from_idx(idx);
@@ -1546,7 +1535,7 @@ int do_syslog(int type, char __user *buf, int len, int source) 
		error = -EINVAL;

		break;

	}

out:



	return error;

}