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 (file)
--- 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 (file)
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 (file)
--- 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 (file)
--- 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