Messages in this thread | | | Date | Sun, 26 Jul 2020 18:34:22 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH 4/4] quota: simplify the quotactl compat handling |
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On Sun, Jul 26, 2020 at 05:32:14PM +0100, Al Viro wrote: > > +static int compat_copy_fs_qfilestat(struct compat_fs_qfilestat __user *to, > > + struct fs_qfilestat *from) > > +{ > > + if (copy_to_user(to, from, sizeof(*to)) || > > + put_user(from->qfs_nextents, &to->qfs_nextents)) > > + return -EFAULT; > > + return 0; > > +} > > do we have any need of that put_user()? Note that you don't even call > that thing unless compat_need_64bit_alignment_fixup() is true. And AFAICS > all such cases are little-endian...
The main reason it is there is to preserve the previous semantics. And no, I don't think we actually need it on x86. But what if some poor souls adds a BE version that needs this? E.g. arm oabi has similar weird alignment, and now imagine someone adding arm64 compat code for that..
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