From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>,
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
Subject: Re: [PATCH 5/9] fs: remove various compat readv/writev helpers
Date: Wed, 23 Sep 2020 16:32:51 +0200 [thread overview]
Message-ID: <20200923143251.GA14062@lst.de> (raw)
In-Reply-To: <20200923142549.GK3421308@ZenIV.linux.org.uk>
On Wed, Sep 23, 2020 at 03:25:49PM +0100, Al Viro wrote:
> 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?
That's a very good question. But it does not just compile but actually
works. Probably because all the syscall wrappers mean that we don't
actually generate the normal names. I just tried this:
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -468,7 +468,7 @@ asmlinkage long sys_lseek(unsigned int fd, off_t offset,
asmlinkage long sys_read(unsigned int fd, char __user *buf, size_t count);
asmlinkage long sys_write(unsigned int fd, const char __user *buf,
size_t count);
-asmlinkage long sys_readv(unsigned long fd,
+asmlinkage long sys_readv(void *fd,
for fun, and the compiler doesn't care either..
next prev parent reply other threads:[~2020-09-23 14:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 6:05 let import_iovec deal with compat_iovecs as well v3 Christoph Hellwig
2020-09-23 6:05 ` [PATCH 1/9] compat.h: fix a spelling error in <linux/compat.h> Christoph Hellwig
2020-09-23 6:05 ` [PATCH 2/9] iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c Christoph Hellwig
2020-09-23 6:05 ` [PATCH 3/9] iov_iter: refactor rw_copy_check_uvector and import_iovec Christoph Hellwig
2020-09-23 14:16 ` Al Viro
2020-09-23 14:38 ` David Laight
2020-09-23 14:49 ` Al Viro
2020-09-23 14:40 ` Al Viro
2020-09-23 6:05 ` [PATCH 4/9] iov_iter: transparently handle compat iovecs in import_iovec Christoph Hellwig
2020-09-23 6:05 ` [PATCH 5/9] fs: remove various compat readv/writev helpers Christoph Hellwig
2020-09-23 14:25 ` Al Viro
2020-09-23 14:32 ` Christoph Hellwig [this message]
2020-09-23 14:59 ` Al Viro
2020-09-23 16:38 ` Al Viro
2020-09-23 17:05 ` Al Viro
2020-09-23 17:46 ` Christoph Hellwig
2020-09-23 17:08 ` Brian Gerst
2020-09-23 18:45 ` Arnd Bergmann
2020-09-23 19:47 ` Al Viro
2020-09-23 19:52 ` Arnd Bergmann
2020-09-23 21:30 ` David Laight
2020-09-23 6:05 ` [PATCH 6/9] fs: remove the compat readv/writev syscalls Christoph Hellwig
2020-09-23 6:05 ` [PATCH 7/9] fs: remove compat_sys_vmsplice Christoph Hellwig
2020-09-23 6:05 ` [PATCH 8/9] mm: remove compat_process_vm_{readv,writev} Christoph Hellwig
2020-09-23 6:05 ` [PATCH 9/9] security/keys: remove compat_keyctl_instantiate_key_iov Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2020-09-25 4:51 let import_iovec deal with compat_iovecs as well v4 Christoph Hellwig
2020-09-25 4:51 ` [PATCH 5/9] fs: remove various compat readv/writev helpers Christoph Hellwig
2020-09-18 12:45 let import_iovec deal with compat_iovecs as well Christoph Hellwig
2020-09-18 12:45 ` [PATCH 5/9] fs: remove various compat readv/writev helpers Christoph Hellwig
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