This is a note to let you know that I've just added the patch titled
firewire: cdev: return -ENOTTY for unimplemented ioctls, not -EINVAL
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
firewire-cdev-return-enotty-for-unimplemented-ioctls-not.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From d873d794235efa590ab3c94d5ee22bb1fab19ac4 Mon Sep 17 00:00:00 2001
From: Stefan Richter <[email protected]>
Date: Sat, 9 Jul 2011 16:42:26 +0200
Subject: firewire: cdev: return -ENOTTY for unimplemented ioctls, not -EINVAL
From: Stefan Richter <[email protected]>
commit d873d794235efa590ab3c94d5ee22bb1fab19ac4 upstream.
On Jun 27 Linus Torvalds wrote:
> The correct error code for "I don't understand this ioctl" is ENOTTY.
> The naming may be odd, but you should think of that error value as a
> "unrecognized ioctl number, you're feeding me random numbers that I
> don't understand and I assume for historical reasons that you tried to
> do some tty operation on me".
[...]
> The EINVAL thing goes way back, and is a disaster. It predates Linux
> itself, as far as I can tell. You'll find lots of man-pages that have
> this line in it:
>
> EINVAL Request or argp is not valid.
>
> and it shows up in POSIX etc. And sadly, it generally shows up
> _before_ the line that says
>
> ENOTTY The specified request does not apply to the kind of object
> that the descriptor d references.
>
> so a lot of people get to the EINVAL, and never even notice the ENOTTY.
[...]
> At least glibc (and hopefully other C libraries) use a _string_ that
> makes much more sense: strerror(ENOTTY) is "Inappropriate ioctl for
> device"
So let's correct this in the <linux/firewire-cdev.h> ABI while it is
still young, relative to distributor adoption.
Side note: We return -ENOTTY not only on _IOC_TYPE or _IOC_NR mismatch,
but also on _IOC_SIZE mismatch. An ioctl with an unsupported size of
argument structure can be seen as an unsupported version of that ioctl.
Signed-off-by: Stefan Richter <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/firewire/core-cdev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -1583,7 +1583,7 @@ static int dispatch_ioctl(struct client
if (_IOC_TYPE(cmd) != '#' ||
_IOC_NR(cmd) >= ARRAY_SIZE(ioctl_handlers) ||
_IOC_SIZE(cmd) > sizeof(buffer))
- return -EINVAL;
+ return -ENOTTY;
if (_IOC_DIR(cmd) == _IOC_READ)
memset(&buffer, 0, _IOC_SIZE(cmd));
Patches currently in stable-queue which might be from [email protected]
are
queue-3.0/firewire-cdev-return-enotty-for-unimplemented-ioctls-not.patch
queue-3.0/firewire-cdev-prevent-race-between-first-get_info-ioctl-and-bus-reset-event-queuing.patch
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