Re: [Outreachy kernel] [PATCH] staging: lustre: llite: dir: Add __user annotations to remove sparse warnings

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Oct 31, 2015 at 03:33:03AM +0530, Amitoj Kaur Chawla wrote:
> This patch fixes the following multiple sparse warnings by adding
> __user annotations:
> 
> warning: incorrect type in argument 1 (different address spaces)
> expected void [noderef] <asn:1>*to got char *<noident>
> warning: incorrect type in argument 1 (different address spaces)
> expected void [noderef] <asn:1>*to got int *<noident>
> warning: incorrect type in argument 1 (different address spaces)
> expected void [noderef] <asn:1>*to got void *<noident>
> warning: incorrect type in argument 2 (different address spaces)
> expected void const [noderef] <asn:1>*from got struct lov_user_md_v3
> warning: incorrect type in argument 2 (different address spaces)
> expected void const [noderef] <asn:1>*from got struct lov_user_md_v1
> warning: incorrect type in argument 1 (different address spaces)
> expected void const [noderef] <asn:1>*from got const char
> 
> After this patch, there are no more sparse warnings for this file.
> 
> Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
> ---
>  drivers/staging/lustre/lustre/llite/dir.c | 71 ++++++++++++++++---------------
>  1 file changed, 36 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c
> index cc6f0f5..da91226 100644
> --- a/drivers/staging/lustre/lustre/llite/dir.c
> +++ b/drivers/staging/lustre/lustre/llite/dir.c
> @@ -1244,6 +1244,9 @@ static long ll_dir_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  	struct ll_sb_info *sbi = ll_i2sbi(inode);
>  	struct obd_ioctl_data *data;
>  	int rc = 0;
> +	int __user *argi = (int __user *)arg;
> +	void __user *argv = (void __user *)arg;
> +	char __user *argc = (char __user *)arg;

It's impossible to fix up lustre with the correct __user markings,
sorry.  The code is horribly designed and probably wrong in places
(kernel semaphore structures in userspace!), so I would just ignore
these warnings, we can't fix them up until the developers of the code do
the work, it's very non-trivial.

sorry.

greg k-h