Move stack parameters for sed_ioctl to prevent oversized stack with CONFIG_KASAN

When CONFIG_KASAN is enabled, compilation fails:

block/sed-opal.c: In function 'sed_ioctl':
block/sed-opal.c:2447:1: error: the frame size of 2256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

Moved all the ioctl structures off the stack and dynamically allocate
using _IOC_SIZE()

Fixes: 455a7b238cd6 ("block: Add Sed-opal library")

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/sed-opal.h b/include/linux/sed-opal.h
index af1a85e..205d520 100644
--- a/include/linux/sed-opal.h
+++ b/include/linux/sed-opal.h
@@ -132,7 +132,7 @@
 #ifdef CONFIG_BLK_SED_OPAL
 bool opal_unlock_from_suspend(struct opal_dev *dev);
 void init_opal_dev(struct opal_dev *opal_dev, sec_send_recv *send_recv);
-int sed_ioctl(struct opal_dev *dev, unsigned int cmd, unsigned long ptr);
+int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *ioctl_ptr);
 
 static inline bool is_sed_ioctl(unsigned int cmd)
 {
@@ -160,7 +160,7 @@
 }
 
 static inline int sed_ioctl(struct opal_dev *dev, unsigned int cmd,
-			    unsigned long ptr)
+			    void __user *ioctl_ptr)
 {
 	return 0;
 }