Re: [PATCH 2/7] signal: factor copy_siginfo_to_external32 from copy_siginfo_to_user32

From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Jeremy Kerr <jk@ozlabs.org>, Arnd Bergmann <arnd@arndb.de>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 2/7] signal: factor copy_siginfo_to_external32 from copy_siginfo_to_user32
Date: Tue, 28 Apr 2020 09:09:35 +0200	[thread overview]
Message-ID: <20200428070935.GE18754@lst.de> (raw)
In-Reply-To: <20200427154050.e431ad7fb228610cc6b95973@linux-foundation.org>

On Mon, Apr 27, 2020 at 03:40:50PM -0700, Andrew Morton wrote:
> > https://www.spinics.net/lists/kernel/msg3473847.html
> > https://www.spinics.net/lists/kernel/msg3473840.html
> > https://www.spinics.net/lists/kernel/msg3473843.html
> 
> OK, but that doesn't necessitate the above monstrosity?  How about
> 
> static int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
> 			     const struct kernel_siginfo *from, bool x32_ABI)
> {
> 	struct compat_siginfo new;
> 	copy_siginfo_to_external32(&new, from);
> 	...
> }
> 
> int copy_siginfo_to_user32(struct compat_siginfo __user *to,
> 			   const struct kernel_siginfo *from)
> {
> #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
> 	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
> #else
> 	return __copy_siginfo_to_user32(to, from, 0);
> #endif
> }
> 
> Or something like that - I didn't try very hard.  We know how to do
> this stuff, and surely this thing isn't how!

I guess that might be a worthwhile middle ground.  Still not a fan of
all these ifdefs..