From: Andi Kleen <ak@muc.de>
To: "Spinka, Kristofer" <kspinka@style.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Unserializing ioctl() system calls
Date: Sat, 22 May 2004 10:03:15 +0200 [thread overview]
Message-ID: <m3n040q470.fsf@averell.firstfloor.org> (raw)
In-Reply-To: <1YuKj-2FZ-9@gated-at.bofh.it> (Kristofer Spinka's message of "Sat, 22 May 2004 04:50:07 +0200")
"Spinka, Kristofer" <kspinka@style.net> writes:
> I noticed that even in the 2.6.6 code, callers to ioctl system call
> (sys_ioctl in fs/ioctl.c) are serialized with {lock,unlock}_kernel().
>
> I realize that many kernel modules, and POSIX for that matter, may not
> be ready to make this more concurrent.
POSIX doesn't care how the kernel implements locking.
> I propose adding a flag to indicate that the underlying module would
> like to support its own concurrency management, and thus we avoid
> grabbing the BKL around the f_op->ioctl call.
Better would be probably a unlocked_ioctl() entry point in f_op. Should
be pretty easy to implement.
There is also the additional issue that on 64bit systems with 32bit
userland the ioctl emulation currently relies on the BKL.
-Andi
next parent reply other threads:[~2004-05-22 8:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1YuKj-2FZ-9@gated-at.bofh.it>
2004-05-22 8:03 ` Andi Kleen [this message]
2004-05-22 2:46 Unserializing ioctl() system calls Spinka, Kristofer
2004-05-22 2:54 ` viro
2004-05-22 3:35 ` Spinka, Kristofer
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