From: Chris Dunlop <chris@onthe.net.au>
Date: Mon, 3 Jun 2013 06:58:52 +0000 (+1000)
Subject: 3.10 API change: block_device_operations->release() returns void
X-Git-Url: https://git.camperquake.de/gitweb.cgi?p=zfs.git;a=commitdiff_plain;h=a1d9543a39942be56879ca9338078afc77c25cea

3.10 API change: block_device_operations->release() returns void

Linux kernel commit torvalds/linux@db2a144 changed the return type
of block_device_operations->release() to void.  Detect the expected
prototype and defined our callout accordingly.

Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1494
---

diff --git a/config/kernel-bdev-block-device-operations.m4 b/config/kernel-bdev-block-device-operations.m4
index 8b5e0a3..faacc19 100644
--- a/config/kernel-bdev-block-device-operations.m4
+++ b/config/kernel-bdev-block-device-operations.m4
@@ -10,7 +10,6 @@ AC_DEFUN([ZFS_AC_KERNEL_BDEV_BLOCK_DEVICE_OPERATIONS], [
 
 		int blk_open(struct block_device *bdev, fmode_t mode)
 		    { return 0; }
-		int blk_release(struct gendisk *g, fmode_t mode) { return 0; }
 		int blk_ioctl(struct block_device *bdev, fmode_t mode,
 		    unsigned x, unsigned long y) { return 0; }
 		int blk_compat_ioctl(struct block_device * bdev, fmode_t mode,
@@ -19,7 +18,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BDEV_BLOCK_DEVICE_OPERATIONS], [
 		static const struct block_device_operations
 		    bops __attribute__ ((unused)) = {
 			.open		= blk_open,
-			.release	= blk_release,
+			.release	= NULL,
 			.ioctl		= blk_ioctl,
 			.compat_ioctl	= blk_compat_ioctl,
 		};
diff --git a/config/kernel-block-device-operations-release-void.m4 b/config/kernel-block-device-operations-release-void.m4
new file mode 100644
index 0000000..a73f858
--- /dev/null
+++ b/config/kernel-block-device-operations-release-void.m4
@@ -0,0 +1,29 @@
+dnl #
+dnl # 3.10.x API change
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID], [
+	AC_MSG_CHECKING([whether block_device_operations.release is void])
+	tmp_flags="$EXTRA_KCFLAGS"
+	EXTRA_KCFLAGS="${NO_UNUSED_BUT_SET_VARIABLE}"
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/blkdev.h>
+
+		void blk_release(struct gendisk *g, fmode_t mode) { return; }
+
+		static const struct block_device_operations
+		    bops __attribute__ ((unused)) = {
+			.open		= NULL,
+			.release	= blk_release,
+			.ioctl		= NULL,
+			.compat_ioctl	= NULL,
+		};
+	],[
+	],[
+		AC_MSG_RESULT(void)
+		AC_DEFINE(HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID, 1,
+		          [struct block_device_operations.release returns void])
+	],[
+		AC_MSG_RESULT(int)
+	])
+	EXTRA_KCFLAGS="$tmp_flags"
+])
diff --git a/config/kernel.m4 b/config/kernel.m4
index 7b8e3b0..46c0255 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -7,6 +7,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_TEST_MODULE
 	ZFS_AC_KERNEL_CONFIG
 	ZFS_AC_KERNEL_BDEV_BLOCK_DEVICE_OPERATIONS
+	ZFS_AC_KERNEL_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
 	ZFS_AC_KERNEL_TYPE_FMODE_T
 	ZFS_AC_KERNEL_KOBJ_NAME_LEN
 	ZFS_AC_KERNEL_3ARG_BLKDEV_GET
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index e35c91b..b516156 100644
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -1024,7 +1024,11 @@ out_mutex:
 	return (error);
 }
 
+#ifdef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
+static void
+#else
 static int
+#endif
 zvol_release(struct gendisk *disk, fmode_t mode)
 {
 	zvol_state_t *zv = disk->private_data;
@@ -1044,7 +1048,9 @@ zvol_release(struct gendisk *disk, fmode_t mode)
 	if (drop_mutex)
 		mutex_exit(&zvol_state_lock);
 
+#ifndef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
 	return (0);
+#endif
 }
 
 static int