On Thu, Sep 11, 2025 at 11:45:38PM +0200, Thorsten Blum wrote:
> Replace kzalloc() followed by copy_from_user() with memdup_user() to
> improve and simplify __hypfs_sprp_ioctl().
>
> Return early if an error occurs instead of trying to allocate memory for
> 'diag304' when memory allocation for 'data' already failed.
>
> No functional changes intended.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx>
> ---
> arch/s390/hypfs/hypfs_sprp.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/arch/s390/hypfs/hypfs_sprp.c b/arch/s390/hypfs/hypfs_sprp.c
> index 9fc3f0dae8f0..be11634bc7db 100644
> --- a/arch/s390/hypfs/hypfs_sprp.c
> +++ b/arch/s390/hypfs/hypfs_sprp.c
> @@ -73,15 +73,16 @@ static int __hypfs_sprp_ioctl(void __user *user_area)
> void *data;
> int rc;
>
> - rc = -ENOMEM;
> data = (void *)get_zeroed_page(GFP_KERNEL);
> - diag304 = kzalloc(sizeof(*diag304), GFP_KERNEL);
> - if (!data || !diag304)
> - goto out;
> + if (!data)
> + return -ENOMEM;
>
> - rc = -EFAULT;
> - if (copy_from_user(diag304, user_area, sizeof(*diag304)))
> + diag304 = memdup_user(user_area, sizeof(*diag304));
> + if (IS_ERR(diag304)) {
> + rc = PTR_ERR(diag304);
> goto out;
> + }
This is not an improvement and also incorrect, since kfree() may now
be called with an error pointer. Please don't send patches like this
which aren't a real improvement. This is just pointless code churn,
and a waste of time.
