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[AMD Official Use Only - AMD Internal Distribution Only]<br>
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I am happy to use EOPNOTSUPP but I must point out that this is not the pattern used across the kernel, the standard is to use ENOTTY, which is also the default that fs/ioctl.c returns when no handler is present. Userspace tooling such as strace and glibc specifically
expectect ENOTTY to indicate invalid or unsupported IOCTL.</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Koenig, Christian <Christian.Koenig@amd.com><br>
<b>Sent:</b> Tuesday, 8 July 2025 5:01 PM<br>
<b>To:</b> McRae, Geoffrey <Geoffrey.McRae@amd.com>; Kuehling, Felix <Felix.Kuehling@amd.com><br>
<b>Cc:</b> Deucher, Alexander <Alexander.Deucher@amd.com>; amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org>; dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org><br>
<b>Subject:</b> Re: [PATCH v2 1/1] drm/amdkfd: return -ENOTTY for unsupported IOCTLs</font>
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<div class="PlainText">On 08.07.25 06:22, Geoffrey McRae wrote:<br>
> Some kfd ioctls may not be available depending on the kernel version the<br>
> user is running, as such we need to report -ENOTTY so userland can<br>
> determine the cause of the ioctl failure.<br>
<br>
In general sounds like a good idea, but ENOTTY is potentially a bit misleading.<br>
<br>
We usually use EOPNOTSUPP for that even if its not the original meaning of that error code.<br>
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Regards,<br>
Christian.<br>
<br>
> <br>
> Signed-off-by: Geoffrey McRae <geoffrey.mcrae@amd.com><br>
> ---<br>
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 8 ++++++--<br>
> 1 file changed, 6 insertions(+), 2 deletions(-)<br>
> <br>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c<br>
> index a2149afa5803..36396b7318e7 100644<br>
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c<br>
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c<br>
> @@ -3253,8 +3253,10 @@ static long kfd_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)<br>
> int retcode = -EINVAL;<br>
> bool ptrace_attached = false;<br>
> <br>
> - if (nr >= AMDKFD_CORE_IOCTL_COUNT)<br>
> + if (nr >= AMDKFD_CORE_IOCTL_COUNT) {<br>
> + retcode = -ENOTTY;<br>
> goto err_i1;<br>
> + }<br>
> <br>
> if ((nr >= AMDKFD_COMMAND_START) && (nr < AMDKFD_COMMAND_END)) {<br>
> u32 amdkfd_size;<br>
> @@ -3267,8 +3269,10 @@ static long kfd_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)<br>
> asize = amdkfd_size;<br>
> <br>
> cmd = ioctl->cmd;<br>
> - } else<br>
> + } else {<br>
> + retcode = -ENOTTY;<br>
> goto err_i1;<br>
> + }<br>
> <br>
> dev_dbg(kfd_device, "ioctl cmd 0x%x (#0x%x), arg 0x%lx\n", cmd, nr, arg);<br>
> <br>
<br>
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