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: Nikitas Angelinas <nikitas.angelinas@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

1 files changed, 12 insertions, 23 deletions

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 87f1a8f4e0f9..cfd9ab1b80c5 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -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;
 }