Linux 3.17 compat: remove wait_on_bit action function

Linux kernel 3.17 removes the action function argument from
wait_on_bit().  Add autoconf test and compatibility macro to support
the new interface.

The former "wait_on_bit" interface required an 'action' function to
be provided which does the actual waiting. There were over 20 such
functions in the kernel, many of them identical, though most cases
can be satisfied by one of just two functions: one which uses
io_schedule() and one which just uses schedule().  This API change
was made to consolidate all of those redundant wait functions.

References: torvalds/linux@7431620

Signed-off-by: Ned Bass <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #378

config/spl-build.m4

@@ -94,6 +94,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
 	SPL_AC_2ARGS_VFS_GETATTR
 	SPL_AC_USLEEP_RANGE
 	SPL_AC_KMEM_CACHE_ALLOCFLAGS
+	SPL_AC_WAIT_ON_BIT
 ])
 
 AC_DEFUN([SPL_AC_MODULE_SYMVERS], [
@@ -2570,3 +2571,28 @@ AC_DEFUN([SPL_AC_KMEM_CACHE_ALLOCFLAGS], [
 		])
 	])
 ])
+
+dnl #
+dnl # 3.17 API change,
+dnl # wait_on_bit() no longer requires an action argument. The former
+dnl # "wait_on_bit" interface required an 'action' function to be provided
+dnl # which does the actual waiting. There were over 20 such functions in the
+dnl # kernel, many of them identical, though most cases can be satisfied by one
+dnl # of just two functions: one which uses io_schedule() and one which just
+dnl # uses schedule().  This API change was made to consolidate all of those
+dnl # redundant wait functions.
+dnl #
+AC_DEFUN([SPL_AC_WAIT_ON_BIT], [
+	AC_MSG_CHECKING([whether wait_on_bit() takes an action])
+	SPL_LINUX_TRY_COMPILE([
+		#include <linux/wait.h>
+	],[
+		int (*action)(void *) = NULL;
+		wait_on_bit(NULL, 0, action, 0);
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_WAIT_ON_BIT_ACTION, 1, [yes])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])

include/linux/Makefile.am

@@ -17,6 +17,7 @@ KERNEL_H = \
 	$(top_srcdir)/include/linux/sysctl_compat.h \
 	$(top_srcdir)/include/linux/time_compat.h \
 	$(top_srcdir)/include/linux/uaccess_compat.h \
+	$(top_srcdir)/include/linux/wait_compat.h \
 	$(top_srcdir)/include/linux/zlib_compat.h
 
 USER_H =

include/linux/wait_compat.h

@@ -0,0 +1,45 @@
+/*****************************************************************************\
+ *  Copyright (C) 2007-2014 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+\*****************************************************************************/
+
+#ifndef _SPL_WAIT_COMPAT_H
+#define _SPL_WAIT_COMPAT_H
+
+
+#ifndef HAVE_WAIT_ON_BIT_ACTION
+#  define spl_wait_on_bit(word, bit, mode) wait_on_bit(word, bit, mode)
+#else
+
+static inline int
+spl_bit_wait(void *word)
+{
+        schedule();
+        return 0;
+}
+
+#define spl_wait_on_bit(word, bit, mode)			\
+	wait_on_bit(word, bit, spl_bit_wait, mode)
+
+#endif /* HAVE_WAIT_ON_BIT_ACTION */
+
+#endif /* SPL_WAIT_COMPAT_H */

include/sys/types.h

@@ -43,6 +43,7 @@
 #include <linux/zlib_compat.h>
 #include <linux/mm_compat.h>
 #include <linux/delay.h>
+#include <linux/wait_compat.h>
 
 #ifndef HAVE_UINTPTR_T
 typedef unsigned long			uintptr_t;

module/spl/spl-kmem.c

@@ -1900,13 +1900,6 @@ spl_cache_grow_wait(spl_kmem_cache_t *skc)
 	return !test_bit(KMC_BIT_GROWING, &skc->skc_flags);
 }
 
-static int
-spl_cache_reclaim_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-
 /*
  * No available objects on any slabs, create a new slab.  Note that this
  * functionality is disabled for KMC_SLAB caches which are backed by the
@@ -1928,8 +1921,8 @@ spl_cache_grow(spl_kmem_cache_t *skc, int flags, void **obj)
 	 * then return so the local magazine can be rechecked for new objects.
 	 */
 	if (test_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
-		rc = wait_on_bit(&skc->skc_flags, KMC_BIT_REAPING,
-		    spl_cache_reclaim_wait, TASK_UNINTERRUPTIBLE);
+		rc = spl_wait_on_bit(&skc->skc_flags, KMC_BIT_REAPING,
+		    TASK_UNINTERRUPTIBLE);
 		SRETURN(rc ? rc : -EAGAIN);
 	}