From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 23 Sep 2020 14:25:49 +0000
Subject: Re: [PATCH 5/9] fs: remove various compat readv/writev helpers
Message-Id: <20200923142549.GK3421308@ZenIV.linux.org.uk>
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References: <20200923060547.16903-1-hch@lst.de>
 <20200923060547.16903-6-hch@lst.de>
In-Reply-To: <20200923060547.16903-6-hch@lst.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>, Jens Axboe <axboe@kernel.dk>, Arnd Bergmann <arnd@arndb.de>, David Howells <dhowells@redhat.com>, David Laight <David.Laight@aculab.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org

On Wed, Sep 23, 2020 at 08:05:43AM +0200, Christoph Hellwig wrote:
>  COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
> -		const struct compat_iovec __user *,vec,
> +		const struct iovec __user *, vec,

Um...  Will it even compile?

>  #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
>  COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
> -		const struct compat_iovec __user *,vec,
> +		const struct iovec __user *, vec,

Ditto.  Look into include/linux/compat.h and you'll see

asmlinkage long compat_sys_preadv64(unsigned long fd,
                const struct compat_iovec __user *vec,
                unsigned long vlen, loff_t pos);

How does that manage to avoid the compiler screaming bloody
murder?