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Subject[PATCH v2 25/27] compat_ioctl: block: simplify compat_blkpg_ioctl()
Date
There is no need to go through a compat_alloc_user_space()
copy any more, just wrap the function in a small helper that
works the same way for native and compat mode.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
block/ioctl.c | 74 ++++++++++++++++++++++++++-------------------------
1 file changed, 38 insertions(+), 36 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index f8c4e2649335..d6911a1149f5 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -12,12 +12,12 @@
#include <linux/pr.h>
#include <linux/uaccess.h>

-static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
+static int blkpg_do_ioctl(struct block_device *bdev,
+ struct blkpg_partition __user *upart, int op)
{
struct block_device *bdevp;
struct gendisk *disk;
struct hd_struct *part, *lpart;
- struct blkpg_ioctl_arg a;
struct blkpg_partition p;
struct disk_part_iter piter;
long long start, length;
@@ -25,9 +25,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user

if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
- return -EFAULT;
- if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
+ if (copy_from_user(&p, upart, sizeof(struct blkpg_partition)))
return -EFAULT;
disk = bdev->bd_disk;
if (bdev != bdev->bd_contains)
@@ -35,7 +33,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
partno = p.pno;
if (partno <= 0)
return -EINVAL;
- switch (a.op) {
+ switch (op) {
case BLKPG_ADD_PARTITION:
start = p.start >> 9;
length = p.length >> 9;
@@ -156,6 +154,39 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
}
}

+static int blkpg_ioctl(struct block_device *bdev,
+ struct blkpg_ioctl_arg __user *arg)
+{
+ struct blkpg_partition __user *udata;
+ int op;
+
+ if (get_user(op, &arg->op) || get_user(udata, &arg->data))
+ return -EFAULT;
+
+ return blkpg_do_ioctl(bdev, udata, op);
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_blkpg_ioctl_arg {
+ compat_int_t op;
+ compat_int_t flags;
+ compat_int_t datalen;
+ compat_caddr_t data;
+};
+
+static int compat_blkpg_ioctl(struct block_device *bdev,
+ struct compat_blkpg_ioctl_arg __user *arg)
+{
+ compat_caddr_t udata;
+ int op;
+
+ if (get_user(op, &arg->op) || get_user(udata, &arg->data))
+ return -EFAULT;
+
+ return blkpg_do_ioctl(bdev, compat_ptr(udata), op);
+}
+#endif
+
static int blkdev_reread_part(struct block_device *bdev)
{
int ret;
@@ -676,35 +707,6 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
EXPORT_SYMBOL_GPL(blkdev_ioctl);

#ifdef CONFIG_COMPAT
-struct compat_blkpg_ioctl_arg {
- compat_int_t op;
- compat_int_t flags;
- compat_int_t datalen;
- compat_caddr_t data;
-};
-
-static int compat_blkpg_ioctl(struct block_device *bdev, fmode_t mode,
- unsigned int cmd, struct compat_blkpg_ioctl_arg __user *ua32)
-{
- struct blkpg_ioctl_arg __user *a = compat_alloc_user_space(sizeof(*a));
- compat_caddr_t udata;
- compat_int_t n;
- int err;
-
- err = get_user(n, &ua32->op);
- err |= put_user(n, &a->op);
- err |= get_user(n, &ua32->flags);
- err |= put_user(n, &a->flags);
- err |= get_user(n, &ua32->datalen);
- err |= put_user(n, &a->datalen);
- err |= get_user(udata, &ua32->data);
- err |= put_user(compat_ptr(udata), &a->data);
- if (err)
- return err;
-
- return blkdev_ioctl(bdev, mode, cmd, (unsigned long)a);
-}
-
#define BLKBSZGET_32 _IOR(0x12, 112, int)
#define BLKBSZSET_32 _IOW(0x12, 113, int)
#define BLKGETSIZE64_32 _IOR(0x12, 114, int)
@@ -767,7 +769,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
return blkdev_ioctl(bdev, mode, BLKBSZSET,
(unsigned long)compat_ptr(arg));
case BLKPG:
- return compat_blkpg_ioctl(bdev, mode, cmd, compat_ptr(arg));
+ return compat_blkpg_ioctl(bdev, compat_ptr(arg));
case BLKRAGET:
case BLKFRAGET:
if (!arg)
--
2.20.0
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