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    Subject[PATCH 22/24] 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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