[PATCH v4 08/10] loop: Rework lo_ioctl() __user argument casting

From: Martijn Coenen
Date: Wed Apr 29 2020 - 10:04:16 EST


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@xxxxxxxxxxx>
---
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 60ba1ed95d77..f172a64333aa 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1659,6 +1659,7 @@ 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) {
@@ -1671,21 +1672,19 @@ 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