iwlwifi: remove log_event debugfs file debugging is disabled

commit 882b7b7d upstream.

When debugging is disabled, the event log functions aren't
functional in the way that the debugfs file expects. This
leads to the debugfs access crashing. Since the event log
functions aren't functional then, remove the debugfs file
when CONFIG_IWLWIFI_DEBUG is not set.
Reported-by: Lekensteyn <lekensteyn@gmail.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/net/wireless/iwlwifi/iwl-trans-pcie.c

@@ -1777,6 +1777,7 @@ static ssize_t iwl_dbgfs_rx_queue_read(struct file *file,
 	return simple_read_from_buffer(user_buf, count, ppos, buf, pos);
 }
 
+#ifdef CONFIG_IWLWIFI_DEBUG
 static ssize_t iwl_dbgfs_log_event_read(struct file *file,
 					 char __user *user_buf,
 					 size_t count, loff_t *ppos)
@@ -1814,6 +1815,7 @@ static ssize_t iwl_dbgfs_log_event_write(struct file *file,
 
 	return count;
 }
+#endif
 
 static ssize_t iwl_dbgfs_interrupt_read(struct file *file,
 					char __user *user_buf,
@@ -1941,7 +1943,9 @@ static ssize_t iwl_dbgfs_fh_reg_read(struct file *file,
 	return ret;
 }
 
+#ifdef CONFIG_IWLWIFI_DEBUG
 DEBUGFS_READ_WRITE_FILE_OPS(log_event);
+#endif
 DEBUGFS_READ_WRITE_FILE_OPS(interrupt);
 DEBUGFS_READ_FILE_OPS(fh_reg);
 DEBUGFS_READ_FILE_OPS(rx_queue);
@@ -1957,7 +1961,9 @@ static int iwl_trans_pcie_dbgfs_register(struct iwl_trans *trans,
 {
 	DEBUGFS_ADD_FILE(rx_queue, dir, S_IRUSR);
 	DEBUGFS_ADD_FILE(tx_queue, dir, S_IRUSR);
+#ifdef CONFIG_IWLWIFI_DEBUG
 	DEBUGFS_ADD_FILE(log_event, dir, S_IWUSR | S_IRUSR);
+#endif
 	DEBUGFS_ADD_FILE(interrupt, dir, S_IWUSR | S_IRUSR);
 	DEBUGFS_ADD_FILE(csr, dir, S_IWUSR);
 	DEBUGFS_ADD_FILE(fh_reg, dir, S_IRUSR);