[jira] [Commented] (HDFS-10257) Quick Thread Local Storage set-up has a small flaw

[Stephen Bovy (JIRA)]

    [ 
https://issues.apache.org/jira/browse/HDFS-10257?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15225669#comment-15225669
 ] 

Stephen Bovy commented on HDFS-10257:
-------------------------------------

When someone wants to use   "HAVE_BETTER_TLS"   (quick thread local storage)

The code should  not execute ""threadLocalStorageSet"   because it is not 
needed and not required.   

The changes I recommended would fix this 

First the  MACRO  "THREAD_LOCAL_STORAGE_SET_QUICK"  should be changed 

so that after  

   quickTlsEnv = (env);   is set   

Then  we should   

   return env;

Secondly   

the order for invoking the MACRO should be changed 

THREAD_LOCAL_STORAGE_SET_QUICK(env);

if (threadLocalStorageSet(env)) 
{ return NULL; } 



> Quick Thread Local Storage set-up has a small flaw
> --------------------------------------------------
>
>                 Key: HDFS-10257
>                 URL: https://issues.apache.org/jira/browse/HDFS-10257
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: libhdfs
>    Affects Versions: 2.6.4
>         Environment: Linux 
>            Reporter: Stephen Bovy
>            Priority: Minor
>   Original Estimate: 72h
>  Remaining Estimate: 72h
>
> In   jni_helper.c   in the   getJNIEnv    function 
> The     “THREAD_LOCAL_STORAGE_SET_QUICK(env);”   Macro   is   in the  wrong 
> location;   
> It should precede   the  “threadLocalStorageSet(env)”   as follows ::  
>     THREAD_LOCAL_STORAGE_SET_QUICK(env);
>     if (threadLocalStorageSet(env)) {
>       return NULL;
>     }
> AND IN   “thread_local_storage.h”   the macro:   
> “THREAD_LOCAL_STORAGE_SET_QUICK”
> should be as follows :: 
> #ifdef HAVE_BETTER_TLS
>   #define THREAD_LOCAL_STORAGE_GET_QUICK() \
>     static __thread JNIEnv *quickTlsEnv = NULL; \
>     { \
>       if (quickTlsEnv) { \
>         return quickTlsEnv; \
>       } \
>     }
>   #define THREAD_LOCAL_STORAGE_SET_QUICK(env) \
>     { \
>       quickTlsEnv = (env); \
>       return env;
>     }
> #else
>   #define THREAD_LOCAL_STORAGE_GET_QUICK()
>   #define THREAD_LOCAL_STORAGE_SET_QUICK(env)
> #endif



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)