wait.h in linux 2.2 and 2.4

[Dave Morrison]

Hi folks,

I've had trouble getting recent versions of arla to compile in the face of
recent changes in the 2.2.x linux kernels.  It seems there've been changes
in linux/wait.h that satisfy arla's check for HAVE_WAIT_QUEUE_HEAD_T, but
which still lack the `task_list' element found in the (almost) 2.4
kernels.  This causes the compilation of xfs/linux/xfs_dev.c to croak.  I
gamely whipped up a new autoconf macro to do the right kind of check and
tweaked the ifdef's in xfs_dev.c to use it.  Maybe it's not exactly the
right thing to do, but it seems to work for me in both the 2.2 and 2.4
worlds.  So, here's a patch against the CVS sources, followed by a new
autoconf macro:

Index: configure.in
===================================================================
RCS file: /stacken-cvs/arla/configure.in,v
retrieving revision 1.437
diff -u -r1.437 configure.in
--- configure.in	2000/09/14 07:19:30	1.437
+++ configure.in	2000/09/22 18:19:17
@@ -1492,6 +1492,7 @@
 smap)
 
 AC_LINUX_TYPE_WAIT_QUEUE_HEAD_T
+AC_LINUX_TYPE_WAIT_QUEUE_TASK_LIST
 AC_LINUX_FUNC_INIT_WAITQUEUE_HEAD
 AC_LINUX_FUNC_INIT_MUTEX
 AC_LINUX_FILLDIR_DT_TYPE
Index: cf/linux-func-init-wait-queue-head.m4
===================================================================
RCS file: /stacken-cvs/arla/cf/linux-func-init-wait-queue-head.m4,v
retrieving revision 1.1
diff -u -r1.1 linux-func-init-wait-queue-head.m4
--- cf/linux-func-init-wait-queue-head.m4	1999/05/16 23:21:54	1.1
+++ cf/linux-func-init-wait-queue-head.m4	2000/09/22 18:19:18
@@ -5,7 +5,8 @@
 AC_DEFUN(AC_LINUX_FUNC_INIT_WAITQUEUE_HEAD, [
 AC_CACHE_CHECK([for init_waitqueue_head],
 ac_cv_func_init_waitqueue_head,[
-AC_TRY_COMPILE_KERNEL([#include <linux/wait.h>],
+AC_TRY_COMPILE_KERNEL([#include <linux/stddef.h>
+#include <linux/wait.h>],
 [wait_queue_head_t foo;
 init_waitqueue_head(&foo)],
 ac_cv_func_init_waitqueue_head=yes,
Index: xfs/linux/xfs_dev.c
===================================================================
RCS file: /stacken-cvs/arla/xfs/linux/xfs_dev.c,v
retrieving revision 1.69
diff -u -r1.69 xfs_dev.c
--- xfs/linux/xfs_dev.c	2000/09/13 04:31:06	1.69
+++ xfs/linux/xfs_dev.c	2000/09/22 18:19:24
@@ -817,7 +817,7 @@
 	for (; t != sleepq; t = t->next) {
 	    printk(" %d", t->message->sequence_num);
 
-#ifdef HAVE_WAIT_QUEUE_HEAD_T
+#ifdef HAVE_WAIT_QUEUE_TASK_LIST
 	    if (!list_empty(&t->wait_queue.task_list)) {
 		const wait_queue_t *w = (const wait_queue_t *)
 		    list_entry(t->wait_queue.task_list.next,
@@ -828,7 +828,7 @@
 #else
 	    if (t->wait_queue && t->wait_queue->task)
 		printk(" (pid %d)", t->wait_queue->task->pid);
-#endif /* !HAVE_WAIT_QUEUE_HEAD_T */
+#endif /* !HAVE_WAIT_QUEUE_TASK_LIST */
 	}
     }
 }

The new autoconf macro:

diff -uN arla-0.34.3/cf/linux-type-wait-queue-task-list.m4
arla/cf/linux-type-wait-queue-task-list.m4
--- arla-0.34.3/cf/linux-type-wait-queue-task-list.m4	Wed Dec 31
19:00:00 1969
+++ arla/cf/linux-type-wait-queue-task-list.m4	Fri Sep 22 14:19:22 2000
@@ -0,0 +1,19 @@
+dnl
+dnl $Id$
+dnl
+
+AC_DEFUN(AC_LINUX_TYPE_WAIT_QUEUE_TASK_LIST, [
+AC_CACHE_CHECK([for wait_queue_task_list],
+ac_cv_type_wait_queue_task_list,[
+AC_TRY_COMPILE_KERNEL([#include <linux/stddef.h>
+#include <linux/wait.h>],
+[wait_queue_head_t foo;
+void *p;
+p = &foo.task_list;],
+ac_cv_type_wait_queue_task_list=yes,
+ac_cv_type_wait_queue_task_list=no)])
+if test "$ac_cv_type_wait_queue_task_list" = "yes"; then
+  AC_DEFINE(HAVE_WAIT_QUEUE_TASK_LIST, 1,
+	[define if you have a wait_queue_task_list])
+fi
+])

Hope this is useful,
Dave

-- 
David Morrison  Brookhaven National Laboratory  phone: 631-344-5840
                Physics Department, Bldg 510 C    fax: 631-344-3253
		          Upton, NY 11973-5000  email: dave at bnl.gov