Linux 6.0 compat: register_shrinker() now var-arg

The 6.0 kernel added a printf-style var-arg for args > 0 to the
register_shrinker function, in order to add names to shrinkers, in
commit e33c267ab70de4249d22d7eab1cc7d68a889bac2. This enables the
shrinkers to have friendly names exposed in /sys/kernel/debug/shrinker/.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes #13748

diff --git a/config/kernel-shrink.m4 b/config/kernel-shrink.m4
index 8cf0f2761bde2c5327e7e9399ad383b86971325c..0c702153e8c4585957725fe240811243a63c3d25 100644 (file)
--- a/config/kernel-shrink.m4
+++ b/config/kernel-shrink.m4
@@ -54,6 +54,21 @@ AC_DEFUN([ZFS_AC_KERNEL_SHRINK_CONTROL_HAS_NID], [
        ])
 ])
 
+AC_DEFUN([ZFS_AC_KERNEL_SRC_REGISTER_SHRINKER_VARARG], [
+       ZFS_LINUX_TEST_SRC([register_shrinker_vararg], [
+               #include <linux/mm.h>
+               unsigned long shrinker_cb(struct shrinker *shrink,
+                   struct shrink_control *sc) { return 0; }
+       ],[
+               struct shrinker cache_shrinker = {
+                       .count_objects = shrinker_cb,
+                       .scan_objects = shrinker_cb,
+                       .seeks = DEFAULT_SEEKS,
+               };
+               register_shrinker(&cache_shrinker, "vararg-reg-shrink-test");
+       ])
+])
+
 AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER_CALLBACK], [
        ZFS_LINUX_TEST_SRC([shrinker_cb_shrink_control], [
                #include <linux/mm.h>
@@ -83,29 +98,50 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER_CALLBACK], [
 
 AC_DEFUN([ZFS_AC_KERNEL_SHRINKER_CALLBACK],[
        dnl #
-       dnl # 3.0 - 3.11 API change
-       dnl # cs->shrink(struct shrinker *, struct shrink_control *sc)
+       dnl # 6.0 API change
+       dnl # register_shrinker() becomes a var-arg function that takes
+       dnl # a printf-style format string as args > 0
        dnl #
-       AC_MSG_CHECKING([whether new 2-argument shrinker exists])
-       ZFS_LINUX_TEST_RESULT([shrinker_cb_shrink_control], [
+       AC_MSG_CHECKING([whether new var-arg register_shrinker() exists])
+       ZFS_LINUX_TEST_RESULT([register_shrinker_vararg], [
                AC_MSG_RESULT(yes)
-               AC_DEFINE(HAVE_SINGLE_SHRINKER_CALLBACK, 1,
-                   [new shrinker callback wants 2 args])
+               AC_DEFINE(HAVE_REGISTER_SHRINKER_VARARG, 1,
+                   [register_shrinker is vararg])
+
+               dnl # We assume that the split shrinker callback exists if the
+               dnl # vararg register_shrinker() exists, because the latter is
+               dnl # a much more recent addition, and the macro test for the
+               dnl # var-arg version only works if the callback is split
+               AC_DEFINE(HAVE_SPLIT_SHRINKER_CALLBACK, 1,
+                       [cs->count_objects exists])
        ],[
                AC_MSG_RESULT(no)
-
                dnl #
-               dnl # 3.12 API change,
-               dnl # cs->shrink() is logically split in to
-               dnl # cs->count_objects() and cs->scan_objects()
+               dnl # 3.0 - 3.11 API change
+               dnl # cs->shrink(struct shrinker *, struct shrink_control *sc)
                dnl #
-               AC_MSG_CHECKING([whether cs->count_objects callback exists])
-               ZFS_LINUX_TEST_RESULT([shrinker_cb_shrink_control_split], [
+               AC_MSG_CHECKING([whether new 2-argument shrinker exists])
+               ZFS_LINUX_TEST_RESULT([shrinker_cb_shrink_control], [
                        AC_MSG_RESULT(yes)
-                       AC_DEFINE(HAVE_SPLIT_SHRINKER_CALLBACK, 1,
-                           [cs->count_objects exists])
+                       AC_DEFINE(HAVE_SINGLE_SHRINKER_CALLBACK, 1,
+                               [new shrinker callback wants 2 args])
                ],[
-                       ZFS_LINUX_TEST_ERROR([shrinker])
+                       AC_MSG_RESULT(no)
+
+                       dnl #
+                       dnl # 3.12 API change,
+                       dnl # cs->shrink() is logically split in to
+                       dnl # cs->count_objects() and cs->scan_objects()
+                       dnl #
+                       AC_MSG_CHECKING([if cs->count_objects callback exists])
+                       ZFS_LINUX_TEST_RESULT(
+                               [shrinker_cb_shrink_control_split],[
+                                       AC_MSG_RESULT(yes)
+                                       AC_DEFINE(HAVE_SPLIT_SHRINKER_CALLBACK, 1,
+                                               [cs->count_objects exists])
+                       ],[
+                                       ZFS_LINUX_TEST_ERROR([shrinker])
+                       ])
                ])
        ])
 ])
@@ -141,6 +177,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER], [
        ZFS_AC_KERNEL_SRC_SHRINK_CONTROL_HAS_NID
        ZFS_AC_KERNEL_SRC_SHRINKER_CALLBACK
        ZFS_AC_KERNEL_SRC_SHRINK_CONTROL_STRUCT
+       ZFS_AC_KERNEL_SRC_REGISTER_SHRINKER_VARARG
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_SHRINKER], [

diff --git a/include/os/linux/spl/sys/shrinker.h b/include/os/linux/spl/sys/shrinker.h
index e5b7a9c955dd922381428088a7e057bb9ed6fb26..d472754be4f40af7676791e34dbffc07ae7561ce 100644 (file)
--- a/include/os/linux/spl/sys/shrinker.h
+++ b/include/os/linux/spl/sys/shrinker.h
@@ -64,7 +64,11 @@
  * }
  */
 
+#ifdef HAVE_REGISTER_SHRINKER_VARARG
+#define        spl_register_shrinker(x)        register_shrinker(x, "zfs-arc-shrinker")
+#else
 #define        spl_register_shrinker(x)        register_shrinker(x)
+#endif
 #define        spl_unregister_shrinker(x)      unregister_shrinker(x)
 
 /*