3.12 compat, 4.0 compat for super_operations shrinker callbacks

3.12 API change - A node ID argument was added to the nr_cached_objects and free_cached_objects callbacks in struct super_operations. 4.0 API change - The node ID and nr_to_scan arguments to the nr_cached_objects and free_cached_objects callbacks in struct super_operations were replaced with a single struct shrink_control argument. Also, the return value from each callback should be long.
openzfs · Apr 19, 2015 · 445ba57 · 445ba57
1 parent e23f2b5
commit 445ba57
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Showing 3 changed files with 125 additions and 14 deletions.
diff --git a/config/kernel-shrink.m4 b/config/kernel-shrink.m4
@@ -72,7 +72,48 @@ AC_DEFUN([ZFS_AC_KERNEL_NR_CACHED_OBJECTS], [
 	ZFS_LINUX_TRY_COMPILE([
 		#include <linux/fs.h>
 
-		int nr_cached_objects(struct super_block *sb) { return 0; }
+		static const struct super_operations so;
+		static const unsigned u = sizeof (so.nr_cached_objects);
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_NR_CACHED_OBJECTS, 1,
+			[sops->nr_cached_objects() exists])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_FREE_CACHED_OBJECTS], [
+	AC_MSG_CHECKING([whether sops->free_cached_objects() exists])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+
+		static const struct super_operations so;
+		static const unsigned u = sizeof (so.free_cached_objects);
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_FREE_CACHED_OBJECTS, 1,
+			[sops->free_cached_objects() exists])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+
+dnl #
+dnl # 3.12 API change
+dnl #
+dnl # A node ID argument was added to the nr_cached_objects and
+dnl # free_cached_objects callbacks in struct super_operations.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_NR_CACHED_OBJECTS_HAS_NID], [
+	AC_MSG_CHECKING([whether sops->nr_cached_objects() has nid argument])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+
+		long nr_cached_objects(struct super_block *sb, int nid) { return 0; }
 
 		static const struct super_operations
 		    sops __attribute__ ((unused)) = {
@@ -81,20 +122,20 @@ AC_DEFUN([ZFS_AC_KERNEL_NR_CACHED_OBJECTS], [
 	],[
 	],[
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_NR_CACHED_OBJECTS, 1,
-			[sops->nr_cached_objects() exists])
+		AC_DEFINE(NR_CACHED_OBJECTS_HAS_NID, 1,
+			[sops->nr_cached_objects() has nid argument])
 	],[
 		AC_MSG_RESULT(no)
 	])
 ])
 
-AC_DEFUN([ZFS_AC_KERNEL_FREE_CACHED_OBJECTS], [
-	AC_MSG_CHECKING([whether sops->free_cached_objects() exists])
+AC_DEFUN([ZFS_AC_KERNEL_FREE_CACHED_OBJECTS_HAS_NID], [
+	AC_MSG_CHECKING([whether sops->free_cached_objects() has nid argument])
 	ZFS_LINUX_TRY_COMPILE([
 		#include <linux/fs.h>
 
-		void free_cached_objects(struct super_block *sb, int x)
-		    { return; }
+		long free_cached_objects(struct super_block *sb, long nr_to_scan,
+		    int nid) { return 0; }
 
 		static const struct super_operations
 		    sops __attribute__ ((unused)) = {
@@ -103,8 +144,59 @@ AC_DEFUN([ZFS_AC_KERNEL_FREE_CACHED_OBJECTS], [
 	],[
 	],[
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_FREE_CACHED_OBJECTS, 1,
-			[sops->free_cached_objects() exists])
+		AC_DEFINE(FREE_CACHED_OBJECTS_HAS_NID, 1,
+			[sops->free_cached_objects() has nid argument])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+dnl #
+dnl # 4.0 API change
+dnl #
+dnl # The node ID and nr_to_scan arguments to the nr_cached_objects and
+dnl # free_cached_objects callbacks in struct super_operations were replaced
+dnl # with a single struct shrink_control argument.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_NR_CACHED_OBJECTS_HAS_SC], [
+	AC_MSG_CHECKING([whether sops->nr_cached_objects() has shrink_control argument])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+
+		long nr_cached_objects(struct super_block *sb,
+		    struct shrink_control sc) { return 0; }
+
+		static const struct super_operations
+		    sops __attribute__ ((unused)) = {
+			.nr_cached_objects = nr_cached_objects,
+		};
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(NR_CACHED_OBJECTS_HAS_SC, 1,
+			[sops->nr_cached_objects() has shrink_control argument])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_FREE_CACHED_OBJECTS_HAS_SC], [
+	AC_MSG_CHECKING([whether sops->free_cached_objects() has shrink_control argument])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+
+		long free_cached_objects(struct super_block *sb,
+		    struct shrink_control sc) { return 0; }
+
+		static const struct super_operations
+		    sops __attribute__ ((unused)) = {
+			.free_cached_objects = free_cached_objects,
+		};
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(NR_CACHED_OBJECTS_HAS_SC, 1,
+			[sops->free_cached_objects() has shrink_control argument])
 	],[
 		AC_MSG_RESULT(no)
 	])

diff --git a/config/kernel.m4 b/config/kernel.m4
@@ -66,7 +66,11 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_EVICT_INODE
 	ZFS_AC_KERNEL_DIRTY_INODE_WITH_FLAGS
 	ZFS_AC_KERNEL_NR_CACHED_OBJECTS
+	ZFS_AC_KERNEL_NR_CACHED_OBJECTS_HAS_NID
+	ZFS_AC_KERNEL_NR_CACHED_OBJECTS_HAS_SC
 	ZFS_AC_KERNEL_FREE_CACHED_OBJECTS
+	ZFS_AC_KERNEL_FREE_CACHED_OBJECTS_HAS_NID
+	ZFS_AC_KERNEL_FREE_CACHED_OBJECTS_HAS_SC
 	ZFS_AC_KERNEL_FALLOCATE
 	ZFS_AC_KERNEL_MKDIR_UMODE_T
 	ZFS_AC_KERNEL_LOOKUP_NAMEIDATA

diff --git a/module/zfs/zpl_super.c b/module/zfs/zpl_super.c
@@ -291,8 +291,15 @@ zpl_prune_sb(int64_t nr_to_scan, void *arg)
 }
 
 #ifdef HAVE_NR_CACHED_OBJECTS
-static int
-zpl_nr_cached_objects(struct super_block *sb)
+static long
+zpl_nr_cached_objects(struct super_block *sb,
+#ifdef NR_CACHED_OBJECTS_HAS_NID
+	int nid
+#endif /* NR_CACHED_OBJECTS_HAS_NID */
+#ifdef NR_CACHED_OBJECTS_HAS_SC
+	struct shrink_control sc
+#endif /* NR_CACHED_OBJECTS_HAS_NID */
+	)
 {
 	zfs_sb_t *zsb = sb->s_fs_info;
 	int nr;
@@ -312,10 +319,18 @@ zpl_nr_cached_objects(struct super_block *sb)
  * just a best effort eviction and the exact values aren't critical so we
  * extrapolate from an object count to a byte size using the znode_t size.
  */
-static void
-zpl_free_cached_objects(struct super_block *sb, int nr_to_scan)
+static long
+zpl_free_cached_objects(struct super_block *sb,
+#ifdef NR_CACHED_OBJECTS_HAS_NID
+	long nr_to_scan, int nid
+#elif defined(NR_CACHED_OBJECTS_HAS_SC)
+	struct shrink_control sc
+#else
+	long nr_to_scan
+#endif
+	)
 {
-	/* noop */
+	return (0);
 }
 #endif /* HAVE_FREE_CACHED_OBJECTS */