From 5b6fe6a693831ef25e6e2244cc236a95ba7c41ee Mon Sep 17 00:00:00 2001
From: Chaskiel M Grundman <cg2v@andrew.cmu.edu>
Date: Mon, 31 Jan 2005 04:25:31 +0000
Subject: [PATCH] STABLE14-linux-tasklist-lock-weak-20050129

FIXES 17424

weak binding to tasklist_lock


(cherry picked from commit 51ec9e099e22e16dbf8aee3333568b9ff26abd3f)
---
 acinclude.m4           |  4 ----
 src/afs/afs_osi.c      | 12 +++++-------
 src/cf/linux-test4.m4  | 17 -----------------
 src/rx/LINUX/rx_knet.c | 12 +++++-------
 4 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index 931de5b7d..e00b904be 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -560,7 +560,6 @@ case $AFS_SYSNAME in *_linux* | *_umlinux*)
 		 LINUX_COMPLETION_H_EXISTS
 		 LINUX_DEFINES_FOR_EACH_PROCESS
 		 LINUX_DEFINES_PREV_TASK
-		 LINUX_EXPORTS_TASKLIST_LOCK
 	         LINUX_FS_STRUCT_ADDRESS_SPACE_HAS_PAGE_LOCK
 	         LINUX_FS_STRUCT_ADDRESS_SPACE_HAS_GFP_MASK
 		 LINUX_FS_STRUCT_INODE_HAS_I_ALLOC_SEM
@@ -636,9 +635,6 @@ case $AFS_SYSNAME in *_linux* | *_umlinux*)
 		 if test "x$ac_cv_linux_exports_sys_wait4" = "xyes" ; then
 		  AC_DEFINE(EXPORTED_SYS_WAIT4, 1, [define if your linux kernel exports sys_wait4])
 		 fi
-		 if test "x$ac_cv_linux_exports_tasklist_lock" = "xyes" ; then
-		  AC_DEFINE(EXPORTED_TASKLIST_LOCK, 1, [define if your linux kernel exports tasklist_lock])
-		 fi
                  if test "x$ac_cv_linux_exports_sys_call_table" = "xyes"; then
                   AC_DEFINE(EXPORTED_SYS_CALL_TABLE)
                  fi
diff --git a/src/afs/afs_osi.c b/src/afs/afs_osi.c
index 2f28f2848..e03e49446 100644
--- a/src/afs/afs_osi.c
+++ b/src/afs/afs_osi.c
@@ -850,14 +850,13 @@ afs_osi_TraverseProcTable(void)
 #endif
 
 #if defined(AFS_LINUX22_ENV)
+extern rwlock_t tasklist_lock __attribute__((weak));
 void
 afs_osi_TraverseProcTable()
 {
     struct task_struct *p;
-
-#ifdef EXPORTED_TASKLIST_LOCK
-    read_lock(&tasklist_lock);
-#endif
+    if (&tasklist_lock)
+       read_lock(&tasklist_lock);
 #ifdef DEFINED_FOR_EACH_PROCESS
     for_each_process(p) if (p->pid) {
 #ifdef STRUCT_TASK_STRUCT_HAS_EXIT_STATE
@@ -881,9 +880,8 @@ afs_osi_TraverseProcTable()
 	afs_GCPAGs_perproc_func(p);
     }
 #endif
-#ifdef EXPORTED_TASKLIST_LOCK
-    read_unlock(&tasklist_lock);
-#endif
+    if (&tasklist_lock)
+       read_unlock(&tasklist_lock);
 }
 #endif
 
diff --git a/src/cf/linux-test4.m4 b/src/cf/linux-test4.m4
index 582f49012..9f30becf6 100644
--- a/src/cf/linux-test4.m4
+++ b/src/cf/linux-test4.m4
@@ -188,23 +188,6 @@ AC_MSG_RESULT($ac_cv_linux_exports_sys_wait4)
 CPPFLAGS="$save_CPPFLAGS"])
 
 
-AC_DEFUN([LINUX_EXPORTS_TASKLIST_LOCK], [
-AC_MSG_CHECKING(for exported tasklist_lock)
-save_CPPFLAGS="$CPPFLAGS"
-CPPFLAGS="-I${LINUX_KERNEL_PATH}/include -I${LINUX_KERNEL_PATH}/include/asm/mach-${SUBARCH} -D__KERNEL__ $CPPFLAGS"
-AC_CACHE_VAL(ac_cv_linux_exports_tasklist_lock,
-[
-AC_TRY_COMPILE(
-[#include <linux/modversions.h>],
-[#ifndef __ver_tasklist_lock
-#error tasklist_lock not exported
-#endif],
-ac_cv_linux_exports_tasklist_lock=yes,
-ac_cv_linux_exports_tasklist_lock=no)])
-AC_MSG_RESULT($ac_cv_linux_exports_tasklist_lock)
-CPPFLAGS="$save_CPPFLAGS"])
-
-
 AC_DEFUN([LINUX_FS_STRUCT_INODE_HAS_I_CDEV], [
 AC_MSG_CHECKING(for i_cdev in struct inode)
 save_CPPFLAGS="$CPPFLAGS"
diff --git a/src/rx/LINUX/rx_knet.c b/src/rx/LINUX/rx_knet.c
index dba89e9f2..5e9b46d77 100644
--- a/src/rx/LINUX/rx_knet.c
+++ b/src/rx/LINUX/rx_knet.c
@@ -194,20 +194,18 @@ osi_NetReceive(osi_socket so, struct sockaddr_in *from, struct iovec *iov,
 
     return code;
 }
-
+extern rwlock_t tasklist_lock __attribute__((weak));
 void
 osi_StopListener(void)
 {
     struct task_struct *listener;
     extern int rxk_ListenerPid;
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
-    read_lock(&tasklist_lock);
-#endif
+    if (&tasklist_lock)
+      read_lock(&tasklist_lock);
     listener = find_task_by_pid(rxk_ListenerPid);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
-    read_unlock(&tasklist_lock);
-#endif
+    if (&tasklist_lock)
+       read_unlock(&tasklist_lock);
     while (rxk_ListenerPid) {
 	flush_signals(listener);
 	force_sig(SIGKILL, listener);
-- 
2.39.5