[Devel] Re: [PATCH] diskquota: 32bit quota tools on 64bit architectures

[Christoph Hellwig]

On Thu, Oct 19, 2006 at 04:32:07PM +0400, Vasily Tarasov wrote:
> +asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
> +						qid_t id, void __user *addr)
> +{
> +	long ret;
> +	unsigned int cmds;
> +	mm_segment_t old_fs;
> +	struct if_dqblk dqblk;
> +	struct if32_dqblk {
> +		__u32 dqb_bhardlimit[2];
> +		__u32 dqb_bsoftlimit[2];
> +		__u32 dqb_curspace[2];
> +		__u32 dqb_ihardlimit[2];
> +		__u32 dqb_isoftlimit[2];
> +		__u32 dqb_curinodes[2];
> +		__u32 dqb_btime[2];
> +		__u32 dqb_itime[2];
> +		__u32 dqb_valid;
> +	} dqblk32;
> +
> +	cmds = cmd >> SUBCMDSHIFT;
> +
> +	switch (cmds) {
> +		case Q_GETQUOTA:
> +			old_fs = get_fs();
> +			set_fs(KERNEL_DS);
> +			ret = sys_quotactl(cmd, special, id, &dqblk);
> +			set_fs(old_fs);

Please allocate the structure using compat_alloc_userspace and copy
with copy_in_user instead of the set_fs trick.