Changeset 0239846 in mainline for uspace/lib/c/generic/loc.c

Timestamp:

2017-11-09T20:25:58Z (6 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

adb1ae9

Parents:

cbdb38ff

Message:

First wait for IPC answer and then end the async exchange

This is necessary to create a parallel locsrv connection (when handling
locsrv requests in parallel) instead of reusing the one which is still
possibly active.

File:

• uspace/lib/c/generic/loc.c (modified) (2 diffs)

uspace/lib/c/generic/loc.c

@@ -247 +247 @@
         sysarg_t retval = async_data_write_start(exch, name, str_size(name));
         
-        loc_exchange_end(exch);
-        
         if (retval != EOK) {
                 async_forget(req);
-                return retval;
-        }
-        
-        exch = loc_exchange_begin(INTERFACE_LOC_SUPPLIER);
+                loc_exchange_end(exch);
+                return retval;
+        }
+        
         async_connect_to_me(exch, 0, 0, 0);
-        loc_exchange_end(exch);
-        
+
+        /*
+         * First wait for the answer and then end the exchange. The opposite
+         * order is generally wrong because it may lead to a deadlock under
+         * certain circumstances.
+         */
         async_wait_for(req, &retval);
+        loc_exchange_end(exch);
+        
         return retval;
 }
@@ -276 +280 @@
         sysarg_t retval = async_data_write_start(exch, fqsn, str_size(fqsn));
         
-        loc_exchange_end(exch);
-        
         if (retval != EOK) {
                 async_forget(req);
-                return retval;
-        }
-        
+                loc_exchange_end(exch);
+                return retval;
+        }
+        
+        /*
+         * First wait for the answer and then end the exchange. The opposite
+         * order is generally wrong because it may lead to a deadlock under
+         * certain circumstances.
+         */
         async_wait_for(req, &retval);
+        loc_exchange_end(exch);
         
         if (retval != EOK) {