From: Andrew Morton <akpm@linux-foundation.org>
To: Namhyung Kim <namhyung@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>, Arnd Bergmann <arnd@arndb.de>,
Phillip Lougher <phillip@lougher.demon.co.uk>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/2] init: add sys-wrapper.h
Date: Fri, 17 Sep 2010 14:40:24 -0700 [thread overview]
Message-ID: <20100917144024.33e66e53.akpm@linux-foundation.org> (raw)
In-Reply-To: <1283268619-10728-2-git-send-email-namhyung@gmail.com>
On Wed, 1 Sep 2010 00:30:18 +0900
Namhyung Kim <namhyung@gmail.com> wrote:
> sys-wrapper.h contains wrapper functions for various syscalls used in init
> code. This wrappers handle proper address space conversion so that it can
> remove a lot of warnings from sparse.
This all looks pretty neat.
> +#define kernel_sys_call(call, ...) \
> +({ \
> + long result; \
> + mm_segment_t old_fs = get_fs(); \
> + set_fs(KERNEL_DS); \
> + result = call(__VA_ARGS__); \
> + set_fs(old_fs); \
> + result; \
> +})
I was worried that some syscalls don't need the set_fs(), and that this
would add overhead. But I see that the patch addresses that.
> - int err = sys_mount(name, "/root", fs, flags, data);
> + int err = kernel_sys_mount(name, "/root", fs, flags, data);
It would be good if we could arrange for _all_ kernel syscalls to use
the wrappers. ie: cause a direct call to sys_mount() to not compile?
I don't know how practical that would be.
next prev parent reply other threads:[~2010-09-17 21:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-31 15:30 [PATCH v4 0/2] init cleanups Namhyung Kim
2010-08-31 15:30 ` [PATCH v4 1/2] init: add sys-wrapper.h Namhyung Kim
2010-09-17 21:40 ` Andrew Morton [this message]
2010-09-18 9:27 ` Arnd Bergmann
2010-09-18 9:50 ` Andrew Morton
2010-08-31 15:30 ` [PATCH v4 2/2] init: use kern_sys_* wrappers instead of syscall Namhyung Kim
2010-09-02 3:26 ` [PATCH v4 2/2] init: use kernel_sys_* " Namhyung Kim
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