Re: [RFC PATCH 03/22] fuse: convert fuse to use iov_iter_copy_[to|from]_user

[Miklos Szeredi]

Dave Kleikamp <dave.kleikamp@xxxxxxxxxx> writes:

> A future patch hides the internals of struct iov_iter, so fuse should
> be using the supported interface.
>
> Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>

Acked-by: Miklos Szeredi <mszeredi@xxxxxxx>

Thanks,
Miklos

> Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
> Cc: fuse-devel@xxxxxxxxxxxxxxxxxxxxx
> ---
>  fs/fuse/file.c |   29 ++++++++---------------------
>  1 file changed, 8 insertions(+), 21 deletions(-)
>
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index 4a199fd..877cee0 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -1582,30 +1582,17 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
>  	while (iov_iter_count(&ii)) {
>  		struct page *page = pages[page_idx++];
>  		size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
> -		void *kaddr;
> +		size_t left;
>  
> -		kaddr = kmap(page);
> -
> -		while (todo) {
> -			char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
> -			size_t iov_len = ii.iov->iov_len - ii.iov_offset;
> -			size_t copy = min(todo, iov_len);
> -			size_t left;
> -
> -			if (!to_user)
> -				left = copy_from_user(kaddr, uaddr, copy);
> -			else
> -				left = copy_to_user(uaddr, kaddr, copy);
> -
> -			if (unlikely(left))
> -				return -EFAULT;
> +		if (!to_user)
> +			left = iov_iter_copy_from_user(page, &ii, 0, todo);
> +		else
> +			left = iov_iter_copy_to_user(page, &ii, 0, todo);
>  
> -			iov_iter_advance(&ii, copy);
> -			todo -= copy;
> -			kaddr += copy;
> -		}
> +		if (unlikely(left))
> +			return -EFAULT;
>  
> -		kunmap(page);
> +		iov_iter_advance(&ii, todo);
>  	}
>  
>  	return 0;
--
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