From: Arnd Bergmann <arnd@arndb.de>
To: linaro-mm-sig@lists.linaro.org
Cc: "Laura Abbott" <labbott@redhat.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"John Stultz" <john.stultz@linaro.org>,
"Arve Hjønnevåg" <arve@android.com>,
"Riley Andrews" <riandrews@android.com>,
devel@driverdev.osuosl.org, "Jon Medhurst" <tixy@linaro.org>,
"Android Kernel Team" <kernel-team@android.com>,
"Liviu Dudau" <Liviu.Dudau@arm.com>,
linux-kernel@vger.kernel.org,
"Jeremy Gebben" <jgebben@codeaurora.org>,
"Eun Taik Lee" <eun.taik.lee@samsung.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Brian Starkey" <brian.starkey@arm.com>,
"Chen Feng" <puck.chen@hisilicon.com>
Subject: Re: [Linaro-mm-sig] [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking
Date: Fri, 02 Sep 2016 11:02:13 +0200 [thread overview]
Message-ID: <7145471.hhkX02hEGi@wuerfel> (raw)
In-Reply-To: <1472769644-11039-4-git-send-email-labbott@redhat.com>
On Thursday, September 1, 2016 3:40:43 PM CEST Laura Abbott wrote:
> --- a/drivers/staging/android/ion/ion-ioctl.c
> +++ b/drivers/staging/android/ion/ion-ioctl.c
> @@ -22,6 +22,29 @@
> #include "ion_priv.h"
> #include "compat_ion.h"
>
> +union ion_ioctl_arg {
> + struct ion_fd_data fd;
> + struct ion_allocation_data allocation;
> + struct ion_handle_data handle;
> + struct ion_custom_data custom;
> + struct ion_abi_version abi_version;
> +};
Are you introducing this, or just clarifying the defintion of the
existing interface. For new interfaces, we should not have a union
as an ioctl argument. Instead each ioctl command should have one
specific structure (or better a scalar argument).
> +static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
> +{
> + int ret = 0;
> +
> + switch (cmd) {
> + case ION_IOC_ABI_VERSION:
> + ret = arg->abi_version.reserved != 0;
> + break;
> + default:
> + break;
> + }
> +
> + return ret ? -EINVAL : 0;
> +}
I agree with Greg, ioctl interfaces should normally not be versioned,
the usual way is to try a command and see if it fails or not.
> +/**
> + * struct ion_abi_version
> + *
> + * @version - current ABI version
> + */
> +
> +#define ION_ABI_VERSION KERNEL_VERSION(0, 1, 0)
> +
> +struct ion_abi_version {
> + __u32 abi_version;
> + __u32 reserved;
> +};
> +
This interface doesn't really need a "reserved" field, you could
as well use a __u32 by itself. If you ever need a second field,
just add a new command number.
Arnd
next prev parent reply other threads:[~2016-09-02 9:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-01 22:40 [PATCHv2 0/4] New Ion ioctls Laura Abbott
2016-09-01 22:40 ` [PATCHv2 1/4] staging: android: ion: Drop heap type masks Laura Abbott
2016-09-02 13:41 ` Brian Starkey
2016-09-02 19:36 ` Laura Abbott
2016-09-05 11:20 ` Brian Starkey
2016-09-06 22:16 ` Laura Abbott
2016-09-07 8:50 ` Brian Starkey
2016-09-01 22:40 ` [PATCHv2 2/4] staging: android: ion: Pull out ion ioctls to a separate file Laura Abbott
2016-09-02 12:44 ` Greg Kroah-Hartman
2016-09-02 19:53 ` Laura Abbott
2016-09-01 22:40 ` [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking Laura Abbott
2016-09-02 6:10 ` Greg Kroah-Hartman
2016-09-02 20:26 ` Laura Abbott
2016-09-02 9:02 ` Arnd Bergmann [this message]
2016-09-02 20:33 ` [Linaro-mm-sig] " Laura Abbott
2016-09-02 21:33 ` Arnd Bergmann
2016-09-02 22:14 ` Laura Abbott
2016-09-01 22:40 ` [PATCHv2 4/4] staging: android: ion: Add ioctl to query available heaps Laura Abbott
2016-09-01 23:44 ` kbuild test robot
2016-09-02 21:27 ` Laura Abbott
2016-09-02 21:37 ` [Linaro-mm-sig] " Arnd Bergmann
2016-09-02 21:53 ` Laura Abbott
2016-09-02 6:14 ` Greg Kroah-Hartman
2016-09-02 20:41 ` Laura Abbott
2016-09-03 12:55 ` Greg Kroah-Hartman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7145471.hhkX02hEGi@wuerfel \
--to=arnd@arndb.de \
--cc=Liviu.Dudau@arm.com \
--cc=arve@android.com \
--cc=brian.starkey@arm.com \
--cc=devel@driverdev.osuosl.org \
--cc=eun.taik.lee@samsung.com \
--cc=gregkh@linuxfoundation.org \
--cc=jgebben@codeaurora.org \
--cc=john.stultz@linaro.org \
--cc=kernel-team@android.com \
--cc=labbott@redhat.com \
--cc=linaro-mm-sig@lists.linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=puck.chen@hisilicon.com \
--cc=riandrews@android.com \
--cc=sumit.semwal@linaro.org \
--cc=tixy@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).