[PATCH v2 4/5] loop: rework lo_ioctl() __user argument casting

[Martijn Coenen <maco@android.com>]

In preparation for a new ioctl that needs to copy_from_user(); makes the
code easier to read as well.

Signed-off-by: Martijn Coenen <maco@android.com>
---
 drivers/block/loop.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f6c6036324bf..b10f1d5306a2 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1658,6 +1658,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
 	unsigned int cmd, unsigned long arg)
 {
 	struct loop_device *lo = bdev->bd_disk->private_data;
+	void __user *argp = (void __user *) arg;
 	int err;
 
 	switch (cmd) {
@@ -1670,21 +1671,19 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
 	case LOOP_SET_STATUS:
 		err = -EPERM;
 		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
-			err = loop_set_status_old(lo,
-					(struct loop_info __user *)arg);
+			err = loop_set_status_old(lo, argp);
 		}
 		break;
 	case LOOP_GET_STATUS:
-		return loop_get_status_old(lo, (struct loop_info __user *) arg);
+		return loop_get_status_old(lo, argp);
 	case LOOP_SET_STATUS64:
 		err = -EPERM;
 		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
-			err = loop_set_status64(lo,
-					(struct loop_info64 __user *) arg);
+			err = loop_set_status64(lo, argp);
 		}
 		break;
 	case LOOP_GET_STATUS64:
-		return loop_get_status64(lo, (struct loop_info64 __user *) arg);
+		return loop_get_status64(lo, argp);
 	case LOOP_SET_CAPACITY:
 	case LOOP_SET_DIRECT_IO:
 	case LOOP_SET_BLOCK_SIZE:
-- 
2.26.2.303.gf8c07b1a785-goog