Linux: Add AC_CHECK_LINUX_OPERATION configure macro

Add a new macro to check the signature of a particular
operation against a provided typed argument list.
One of the arguments is an arbitrary label that is used
to construct the pre-processor define name.  This will
allow for testing of different forms for the same
operation.

This can be used to replace many of the remaining odd
checks in src/cf/linux_test4.m4.

Change-Id: Ic619ace54f81aa8e1eb744e2d11f541a303b9587
Reviewed-on: http://gerrit.openafs.org/11927
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>

diff --git a/src/cf/linux-test1.m4 b/src/cf/linux-test1.m4
index 4e799e2..95e4af0 100644 (file)
--- a/src/cf/linux-test1.m4
+++ b/src/cf/linux-test1.m4
@@ -150,3 +150,18 @@ AC_DEFUN([AC_CHECK_LINUX_TYPED_STRUCT],
                       [Define if kernel $1 has the $2 element])
  ])
 
+dnl AC_CHECK_LINUX_OPERATION([structure], [operation], [label], [includes], [return_type], [args])
+AC_DEFUN([AC_CHECK_LINUX_OPERATION],
+ [AS_VAR_PUSHDEF([ac_linux_operation], [ac_cv_linux_operation_$1_$2_$3])
+  AC_CACHE_CHECK([operation $2 in $1], [ac_linux_operation],
+    [save_CPPFLAGS="$CPPFLAGS"
+     CPPFLAGS="$CPPFLAGS -Werror"
+     AC_TRY_KBUILD([$4], [struct $1 ops; $5 op($6) { return ($5)0; }; ops.$2 = op;],
+                  AS_VAR_SET([ac_linux_operation], [yes]),
+                  AS_VAR_SET([ac_linux_operation], [no]))
+     CPPFLAGS="$save_CPPFLAGS"
+    ])
+  AS_IF([test AS_VAR_GET([ac_linux_operation]) = yes],
+       [AC_DEFINE(AS_TR_CPP(HAVE_LINUX_$1_$2_$3), 1,
+                  [Define if $1 has $2 operation of form $6])])
+ ])